Synthesis, structures, and reactions of titanium, scandium, and yttrium complexes of diamino-bis(phenolate) ligands: Monomeric, dimeric, neutral, cationic, and multiply bonded derivatives

Article abstract of DOI:10.1021/om0493661

The synthesis, structures, and selected reactions of new scandium, yttrium, and titanium compounds containing the O₂^RNN ligands are discussed. The O₂^RNN ligands can enforce six-coordination, resulting in the for

Full text of DOI:10.1021/om0493661

Organometallics 2005, 24, 309-330
309
Synthesis, Structures, and Reactions of Titanium,
Scandium, and Yttrium Complexes of
Diamino-bis(phenolate) Ligands: Monomeric, Dimeric,
Neutral, Cationic, and Multiply Bonded Derivatives
Catherine L. Boyd, Thierry Toupance, Ben R. Tyrrell, Benjamin D. Ward,
Claire R. Wilson, Andrew R. Cowley, and Philip Mountford*
Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
Received August 15, 2004
New groups 3 and 4 organometallic and coordination compounds supported by the
R
tetradentate diamino-bis(phenolate) ligands O2tBuNN′ and O2MeNN′ are reported [H2O2 NN′
t
) (2-C5H4N)CH2N(2-HO-3,5-C6H2R2)2 where R ) Bu or Me] along with some comparative
studies with the tridentate amino-bis(phenolate) ligand O2tBuN (H2O2tBuN ) PrN(2-HO-
n
t
3,5-C6H2 Bu2)2). Reaction of Na2O2tBuNN′ with ScCl3 and pyridine in THF gave monomeric
Me
Sc(O2tBuNN′)Cl(py) (2), whereas Na2O2MeNN′ gave the dimeric phenoxy-bridged Sc2(O2
-
NN′)2Cl2 (3). Reaction of Na2O2tBuNN′ and YCl3 in neat pyridine gave the chloride-bridged,
seven-coordinate dimer Y2(O2tBuNN′)2(µ-Cl)2(py)2 (4). Reaction of M(CH2SiMe3)3(THF)2 (M
) Sc or Y) with H2O2tBuNN′ afforded M(O2tBuNN′)(CH2SiMe3)(THF). The one-pot reaction of
R
t
ScCl3 with Na2O2 NN′ (R ) Bu or Me) and Li[PhC(NSiMe3)2] gave the fluxional benza-
R
R
midinate derivatives Sc(O2 NN′){PhC(NSiMe3)2}. Treatment of Ti(NMe2)4 with H2O2 NN′
R
gave the corresponding Ti(O2 NN′)(NMe2)2 (R ) tBu (11) or Me); 11 in turn reacts with HS-
4-C6H4Me to give Ti(O2tBuNN′)(NMe2)(S-4-C6H4Me). One-pot reactions of TiCl4(THF)2 with
R
R
MeLi (2 equiv) followed by H2O2 NN′ affords Ti(O2 NN′)Cl2 (R ) tBu (9) or Me (10)), which
R
t
are cleanly methylated with MeMgBr to yield the corresponding Ti(O2 NN′)Me2 (R ) Bu
(14) or Me (15)). The terminal imidotitanium compounds Ti(O2tBuNN′)(NR)(py) (R ) Bu or
t
2,6-C6H3Me2) were formed from the respective Ti(NR)Cl2(py)3 reagents and Na2O2tBuNN′,
and these react with CO2 by imido group transfer to yield the µ-oxo dimer Ti2(O2tBuNN′)2-
(µ-O)2 (18) and RNCO. The related five-coordinate compounds Ti(O2tBuN)(NR)(py) (R ) tBu,
i
2,6-C6H3Me2 (20) or 2,6-C6H3 Pr2 (21)) were prepared in an analogous manner. These do not
give identifiable metal products with CO2. Treatment of the dimethyl compounds 14 or 15
with B(ArF)3 or [CPh3][B(ArF)4] (ArF ) C6F5) gave the fluxional, dimeric phenoxy-bridged
R
cations [Ti2(O2 NN′)2Me2]2+, which show very sluggish 1-hexene polymerization behavior.
The compounds 2, 3, 4, 11, 9, 10, 16, 18, 20, and 21 have been crystallographically
characterized.
Introduction
CH2NSiMe2R)2 (abbreviated as N2NN′ where R ) Me
t
or Bu).5,6 These dianionic, tetradentate ligands can be
In the drive to extend the non-metallocene chemistry
of the early to mid-transition elements, much progress
has been made with mono- and polyanionic N-donor
ligands.1-4 One of our contributions has been to intro-
duce the diamino-diamide ligands (2-C5H4N)CH2N(CH2-
useful supporting environments for groups 3, 4, and 5,
six- and five-coordinate complexes of the general type
M(A)(B)(N2NN′) and M(A)(N2NN′) (I, Chart 1). How-
ever, some of the reaction chemistry of these systems
has been hampered by side-reactions involving the
amido N-substituents, and for this reason we have been
developing parallel studies with the corresponding
diamino-bis(phenoxide) ligands O2RNN′ (R ) tBu or Me;
see Chart 1). We recently reported in full the synthesis
and structures of a range of neutral and cationic
* Corresponding author. E-mail: philip.mountford@chem.ox.ac.uk.
(1) Selected reviews on anionic N-donor ligand chemistry: Gade,
L. H. Chem. Commun. 2000, 173. Kempe, R. Angew. Chem., Int. Ed.
2000, 39, 468. Brand, H.; Arnold, J. Coord. Chem. Rev. 1995, 140, 137.
Mountford, P. Chem. Soc. Rev. 1998, 27, 105. Schrock, R. R. Acc. Chem.
Res. 1997, 30, 9. Gade, L. H.; Mountford, P. Coord. Chem. Rev. 2001,
216-217, 65. Wigley, D. E. Prog. Inorg. Chem. 1994, 42, 239.
(2) Most developments in the area of “post-metallocene” chemistry
have been in the context of polymerization catalysis. For recent reviews
see: Coates, G. W. J. Chem. Soc., Dalton Trans. 2002, 467. Hou, Z.;
Wakatsuki, Y. Coord. Chem. Rev. 2002, 231, 1. Gibson, V. C.;
Spitzmesser, S. K. Chem. Rev. 2003, 103, 283. Gromada, J.; Carpentier,
J.-F.; Mortreux, A. Coord. Chem. Rev. 2004, 248, 397. Bolton, P. D.;
Mountford, P. Adv. Synth. Catal. 2005, accepted for publication.
(3) For recent reviews of post-metallocene group 3 chemistry in
general see: Piers, W. E.; Emslie, D. J. H. Coord. Chem. Rev. 2002,
233, 131. Mountford, P.; Ward, B. D. Chem. Commun. 2003, 1797
(Feature article review).
(4) For recent reviews of phenoxy-based olefin polymerization
catalysts see: Suzuki, Y.; Terao H.; Fujita, T. Bull. Chem. Soc. Jpn.
2003, 76, 1493. Mitani, M.; Saito, J.; Ishii, S.; Nakayama, Y.; Makio,
H.; Matsukawa, N.; Matsui, S.; Mohri, J.; Furuyama, R.; Terao, H.;
Bando, H.; Tanaka H.; Fujita, T. Chem. Rec. 2004, 4, 137.
(5) Skinner, M. E. G.; Cowhig, D. A.; Mountford, P. Chem. Commun.
2000, 1167. Skinner, M. E. G.; Mountford, P. J. Chem. Soc., Dalton
Trans. 2002, 1694.
(6) Skinner, M. E. G.; Li, Y.; Mountford, P. Inorg. Chem. 2002, 41,
1110.
10.1021/om0493661 CCC: $30.25 © 2005 American Chemical Society
Publication on Web 12/13/2004

310 Organometallics, Vol. 24, No. 2, 2005
Boyd et al.
Chart 1
Scheme 1. Synthesis of Group 3 Chloride
Complexes of O2RNN′ (R ) Me or Bu)
t
zirconium organometallic complexes with these ligands.7
Kol et al. have reported extensively on olefin polymer-
ization (in some instances living) by titanium and
R
zirconium dibenzyls supported by ligands related to O2 -
NN′ but almost exclusively with the pyridyl moiety
replaced by etheral O- or tertiary amino N-donors.8-14
We were the first to use the O2RNN′ ligand in group
3,15 and more recently Carpentier16 and Kerton17 have
applied other members of this family (i.e., other donors
in place of pyridyl) in catalytic studies using group 3
and lanthanide derivatives. A range of other dianionic
O2N2-donor ligands have been applied recently (some-
times with great effect) in groups 3 and 4 and lan-
thanide chemistry.2,3,18,19
the O2RNN′ ligands. In one instance comparative studies
have been made for the tridentate analogue O2tBuN (see
Chart 1). Part of this work has been communicated.15
Results and Discussion
The protio ligands (Chart 1) H2O2RNN′ (R ) tBu20 and
Me7) and H2O2tBuN10 were prepared according to meth-
ods described by us and others. The sodium salts
Na2O2RNN′ were prepared by our previously reported
methods,7 namely, reaction of H2O2RNN′ with NaH (2
equiv) in THF. The spectroscopically pure compound
Na2O2tBuN (1) was prepared in an analogous way (92%
yield), and an analytically pure form (Na2O2tBuN‚THF)
was obtained from THF/pentane. It is likely that all
three sodium compounds exist as multiples of the simple
formula units given here, but without structural data
is it neither possible nor appropriate to comment
further.
In this contribution we report our studies of the
synthesis. structures, and selected reactions of new
scandium, yttrium, and titanium compounds containing
(7) Toupance, T.; Dubberley, S. R.; Rees, N. H.; Tyrrell, B. R.;
Mountford, P. Organometallics 2002, 21, 1367.
(8) Tshuva, E. Y.; Goldberg, I.; Kol, M.; Goldschmidt, Z. Inorg. Chem.
Commun. 2000, 3, 611.
(9) Tshuva, E. Y.; Goldberg, I.; Kol, M.; Goldschmidt, Z. Chem.
Commun. 2001, 2120.
(10) Tshuva, E. Y.; Goldberg, I.; Kol, M.; Goldschmidt, Z. Inorg.
Chem. 2001, 40, 4263.
(11) Tshuva, E. T.; Goldberg, I.; Kol, M.; Goldschmidt, Z. Organo-
metallics 2001, 20, 3017.
(12) Tshuva, E. T.; Groysman, S.; Goldberg, I.; Kol, M.; Goldschmidt,
Z. Organometallics 2002, 21, 662.
Scandium and Yttrium Complexes of O2RNN′.
The new chemistry is summarized in Scheme 1. Reac-
tion of Na2O2tBuNN′ with either ScCl3 or preformed
ScCl3(THF)3 in THF afforded mixtures of products,
which appeared from their NMR spectra to contain both
Cs and C1 symmetric species. The relative composition
of the mixtures changed with handling (i.e., evaporation,
re-extraction), and we speculated that THF loss might
be occurring. Repeating the reaction with the addition
(13) Groysman, S.; Goldberg, I.; Kol, M.; Genizi, E.; Goldschmidt,
Z. Organometallics 2003, 22, 3013.
(14) Groysman, S.; Goldberg, I.; Kol, M.; Genizi, E.; Goldschmidt,
Z. Inorg. Chim. Acta 2003, 345, 137.
(15) Skinner, M. E. G.; Tyrrell, B. R.; Ward, B. D.; Mountford, P. J.
Organomet. Chem. 2002, 647, 145 (special theme issue on group 3 and
lanthanide chemistry).
(16) Cai, C.-X.; Amgoune, A.; Lehmann, C. W.; Carpentier, J.-F.
Chem. Commun. 2004, 330. Cai, C.-X.; Toupet, L.; Lehmann, C. W.;
Carpentier, J.-F. J. Organomet. Chem. 2003, 683, 131.
(17) Kerton, F. M.; Whitwood, A. C.; Willans, C. E. Dalton Trans.
2004, 2237.
(18) For recent chemistry with O2N2 donor ligands in group 3 see:
O’Shaughnessy, P. N.; Knight, P. D.; Morton, C.; Gillespie, K. M.; Scott,
P. Chem. Commun. 2003, 1770. Emslie, D. J. H.; Piers, W. E.; Parvez,
M. Dalton. Trans. 2003, 2615. Lara-Sanchez, A.; Rogriguez, A.; Hughes,
D. L.; Schormann, M.; Bochmann, M. J. Organomet. Chem. 2002, 663,
63. Emslie, D. J. H.; Piers, W. E.; Parvez, M.; McDonald, R. Organo-
metallics 2002, 21, 4226. Evans, W. J.; Fujimoto, C. H.; Ziller, J. W.
Polyhedron 2002, 21, 1683.
(19) For group 4 phenoxy-imine catalysts see the following and
references therein: Furuyama, R.; Saito, J.; Ishii, S.; Mitani, M.;
Matsui, S.; Tohi, Y.; Makio, H.; Matsukawa, N.; Tanaka, H.; Fujita,
T. J. Mol. Catal. A: Chem. 2003, 200, 31. Hustad, P. D.; Coates, G.
W. J. Am. Chem. Soc. 2002, 124, 11578. Reinartz, S.; Mason, A. F.;
Lobkovsky, E. B.; Coates, G. W. Organometallics 2003, 22, 2542.
(20) Shimazaki, Y.; Huth, S.; Odani, A.; Yamauchi, O. Angew. Chem.,
Int. Ed. 2000, 39, 1666.

Diamino-bis(phenolate) Ti, Sc, and Y Complexes
Organometallics, Vol. 24, No. 2, 2005 311
Table 1. Selected Bond Lengths (Å) and Angles
(deg) for Sc(O2tBuNN′)Cl(py) (2)
Sc(1)-Cl(1)
Sc(1)-N(2)
Sc(1)-O(1)
O(1)-C(1)
2.431(2)
2.381(5)
2.002(4)
1.354(7)
Sc(1)-N(1)
Sc(1)-N(3)
Sc(1)-O(2)
O(2)-C(15)
2.303(6)
2.310(5)
1.968(4)
1.329(7)
Cl(1)-Sc(1)-N(1)
N(1)-Sc(1)-N(2)
96.3(2)
73.2(2)
Cl(1)-Sc(1)-N(2) 167.66(14)
Cl(1)-Sc(1)-N(3)
N(2)-Sc(1)-N(3)
97.7(2)
93.5(2)
86.2(2)
85.1(2)
96.8(2)
88.0(2)
N(1)-Sc(1)-N(3) 164.7(2)
Cl(1)-Sc(1)-O(1) 101.29(14) N(1)-Sc(1)-O(1)
N(2)-Sc(1)-O(1)
Cl(1)-Sc(1)-O(2)
N(2)-Sc(1)-O(2)
84.8(2)
94.78(14) N(1)-Sc(1)-O(2)
80.4(2) N(3)-Sc(1)-O(2)
N(3)-Sc(1)-O(1)
O(1)-Sc(1)-O(2) 163.2(2)
Sc(1)-O(1)-C(1) 129.5(4)
Sc(1)-N(1)-C(32) 117.4(4)
Sc(1)-O(2)-C(15) 144.6(4)
Table 2. Selected Bond Lengths (Å) and Angles
(deg) for Sc2(O2MeNN′)2Cl2 (3)
Sc(1)-O(1)
Sc(1)-O(2)
Sc(1)-N(2)
O(1)-C(1)
2.1222(12)
1.9443(13)
2.387(2)
Sc(1)-O(1A)
Sc(1)-N(1)
Sc(1)-Cl(1)
O(2)-C(10)
2.1386(13)
2.386(2)
2.4269(5)
1.342(2)
1.378(2)
O(1)-Sc(1)-O(1A)
O(1A)-Sc(1)-O(2)
72.98(5)
94.44(5)
O(1)-Sc(1)-O(2)
O(1)-Sc(1)-N(1)
155.09(5)
88.96(5)
104.52(6)
111.78(5)
71.03(5)
93.57(4)
83.77(4)
Figure 1. Displacement ellipsoid plot (20% probability)
of Sc(O2tBuNN′)Cl(py)‚C6H6 (2‚C6H6). H atoms and C6H6
molecule of crystallization omitted for clarity.
O(1A)-Sc(1)-N(1) 161.00(5) O(2)-Sc(1)-N(1)
O(1)-Sc(1)-N(2)
O(2)-Sc(1)-N(2)
84.06(5)
80.82(5)
O(1A)-Sc(1)-N(2)
N(1)-Sc(1)-N(2)
O(1)-Sc(1)-Cl(1) 100.53(4) O(1A)-Sc(1)-Cl(1)
O(2)-Sc(1)-Cl(1) 101.68(4) N(1)-Sc(1)-Cl(1)
of pyridine (Scheme 1) led to the single monomeric, Cs
symmetric six-coordinate pyridine adduct Sc(O2tBuNN′)-
Cl(py) (2) in 59% yield after crystallization from ben-
zene. The X-ray molecular structure is shown in Figure
1, and selected bond lengths are listed in Table 1. The
structure confirms that given in Scheme 1 and will be
discussed further below. Application of prolonged dy-
namic vacuum to 2 lead to pyridine loss and the
appearance of a second (C1 symmetric) species. The
mixtures could always be converted back to pure 2 on
the addition of pyridine, but a pure pyridine-free sample
could not be isolated free of 2.
N(2)-Sc(1)-Cl(1) 154.36(4) Sc(1)-O(1)-Sc(1A) 107.02(5)
Sc(1)-O(1)-C(1)
118.8(1)
Sc(1A)-O(1)-C(1)
131.7(1)
Sc(1)-O(2)-C(10) 142.32(12) Sc(1)-O(1A)-C(1A) 131.6(1)
The X-ray molecular structure is shown in Figure 2, and
selected metric parameters are summarized in Table 2;
these will be discussed further below. For the larger
congener yttrium, only the reaction of YCl3 with Na2O2
NN′ afforded a single product, and again pyridine (this
time as solvent) was required in order to obtain a single
well-defined product. Thus the dimeric complex Y2(O2
NN′)2(µ-Cl)2(py)2 (4) was isolated in 74% yield as a
bright white powder after recrystallization from benzene/
pentane. The X-ray molecular structure is shown in
Figure 3, and distances and angles associated with the
two yttrium centers are listed in Table 3.
tBu
-
tBu
-
Reaction of Na2O2MeNN′ (a sterically less demanding
ligand) with ScCl3 in THF gave the base-free dimeric
complex Sc2(O2MeNN′)2Cl2 (3) in 45% recrystallized yield.
Figure 2. Displacement ellipsoid plot (35% probability) of Sc2(O2MeNN′)2Cl2‚2CH2Cl2 (3‚2CH2Cl2). H atoms and CH2Cl2
molecules of crystallization omitted for clarity.

312 Organometallics, Vol. 24, No. 2, 2005
Boyd et al.
the Sc-Cl vector), presumably contributes to the need
to have an additional sixth ligand occupying the pyri-
dine site in 2. The NMR data for 2 are fully consistent
with the solid state structure. At ambient temperature
the pyridine resonances are rather broad, consistent
with a dissociative dynamic equilibrium between 2 and
a pyridine-free homologue. The NMR data reported in
the Experimental Section were recorded at 279 K, at
which temperature the pyridine resonances are sharp
and all H-H couplings can be clearly resolved.
The scandium centers in dimeric 3 (Figure 2) are also
six-coordinate but involve bridging phenoxide oxygens
(not chlorides). The asymmetric unit of 3‚2CH2Cl2
contains two half-molecules of Sc2(O2MeNN′)2Cl2 (lying
across crystallographic inversion centers) and two mol-
ecules of co-crystallized dichloromethane. No significant
differences were observed between the two independent
molecules of 3, and for the purposes of this discussion
only that containing Sc(1) will be considered. The
structure of compound 3 is somewhat similar to Sc2(L2)-
(DMSO)2 (L ) p-tert-butyloxacalix[3]arene), which also
possesses a Sc2(µ-O)2 core with bridging phenoxy link-
ages.23 The distances about Sc(1) in 3 are rather similar
to those in monomeric 2 with the expected exception of
the slightly longer distances to the bridging oxygen
atoms in 3. The NMR spectra of 3 are sharp at room
temperature and fully consistent with the solid state
structure. In particular there are clear resonances for
two inequivalent phenoxymethyl “arms” for the bridging
and nonbridging oxygens.
Figure 3. Displacement ellipsoid plot (25% probability)
of Y2(O2tBuNN′)2(µ-Cl)2(py)2‚3(C6H6) (4‚3C6H6). H atoms and
C6H6 molecules of crystallization omitted for clarity.
Table 3. Selected Bond Lengths (Å) and Angles
(deg) for Y2(O2tBuNN′)2(µ-Cl)2(py)2 (4)
Y(1)-Cl(1)
Y(2)-Cl(1)
Y(1)-O(1)
Y(2)-O(3)
Y(1)-N(1)
Y(1)-N(3)
Y(2)-N(5)
2.744(2)
2.792(2)
2.139(5)
2.152(6)
2.520(7)
2.534(7)
2.594(7)
Y(1)-Cl(2)
Y(2)-Cl(2)
Y(1)-O(2)
Y(2)-O(4)
Y(1)-N(2)
Y(2)-N(4)
Y(2)-N(6)
2.789(2)
2.740(2)
2.155(6)
2.132(6)
2.595(7)
2.486(7)
2.512(6)
Cl(1)-Y(1)-Cl(2)
Cl(1)-Y(1)-O(1)
Cl(2)-Y(1)-O(1)
Cl(1)-Y(1)-O(2)
Cl(2)-Y(1)-O(2)
O(1)-Y(1)-O(2)
Cl(1)-Y(1)-N(1)
Cl(2)-Y(1)-N(1)
O(1)-Y(1)-N(1)
O(2)-Y(1)-N(1)
Cl(1)-Y(1)-N(2)
Cl(2)-Y(1)-N(2)
O(1)-Y(1)-N(2)
O(2)-Y(1)-N(2)
N(1)-Y(1)-N(2)
Cl(1)-Y(1)-N(3)
Cl(2)-Y(1)-N(3)
O(1)-Y(1)-N(3)
O(2)-Y(1)-N(3)
N(1)-Y(1)-N(3)
N(2)-Y(1)-N(3)
Y(1)-Cl(1)-Y(2)
Y(1)-O(1)-C(1)
Y(1)-O(2)-C(15)
71.91(7)
87.1(2)
118.1(2)
119.8(2)
82.3(2)
151.3(2)
78.3(2)
129.6(2)
99.5(2)
78.4(2)
137.1(2)
150.6(2)
75.0(2)
78.0(2)
67.1(2)
133.3(2)
74.0(2)
81.7(2)
85.6(2)
148.2(2)
82.9(2)
107.19(8)
146.1(5)
136.7(6)
Cl(1)-Y(2)-Cl(2)
Cl(1)-Y(2)-O(3)
Cl(2)-Y(2)-O(3)
Cl(1)-Y(2)-O(4)
Cl(2)-Y(2)-O(4)
O(3)-Y(2)-O(4)
Cl(1)-Y(2)-N(4)
Cl(2)-Y(2)-N(4)
O(3)-Y(2)-N(4)
O(4)-Y(2)-N(4)
Cl(1)-Y(2)-N(5)
Cl(2)-Y(2)-N(5)
O(3)-Y(2)-N(5)
O(4)-Y(2)-N(5)
N(4)-Y(2)-N(5)
Cl(1)-Y(2)-N(6)
Cl(2)-Y(2)-N(6)
O(3)-Y(2)-N(6)
O(4)-Y(2)-N(6)
N(4)-Y(2)-N(6)
N(5)-Y(2)-N(6)
Y(1)-Cl(2)-Y(2)
Y(2)-O(3)-C(42)
Y(2)-O(4)-C(56)
71.93(7)
84.1(2)
120.4(2)
117.4(2)
86.4(2)
150.9(2)
131.9(2)
79.4(2)
The dimeric congener Y2(O2tBuNN′)2(µ-Cl)2(py)2 (4,
Figure 3) possesses bridging chloride ligands rather
than dimerizing via the phenoxy oxygens as in 3
(possibly owing to the larger ortho tert-butyl ring
substituents in the former). In addition, the larger metal
accommodates a pyridine molecule at each yttrium,
giving seven-coordinate centers. The molecules have
approximate C2 symmetry (rotation axis perpendicular
to the Y2(µ-Cl)2 plane). The yttrium centers possess
distorted capped trigonal prismatic geometries, the
capping atoms being the tripodal amine nitrogens. The
prisms are linked by the two µ-Cl atoms, which lie on
the mutual edge of the two noncapped faces of the
respective prisms. The only other complex containing a
Y2(µ-Cl)2 core and seven-coordinate yttrium atoms is
Y2(tBu2salen)2(µ-Cl)2(THF)2,24 and the geometry of 4 is
similar to this. The bond parameters for 4 are within
the previously found ranges.21,22 Unlike with 2, no room-
temperature broadening of the pyridine resonances was
observed for 4, indicating that no dissociation of the
pyridine ligands occurs on the NMR time scale. The
NMR spectra of 4 in dichloromethane-d2 were not
entirely consistent with the solid state structure. In
Figure 3 the two phenoxy rings of 4 are not equivalent,
but in the NMR spectra resonances for only a single Cs
symmetric O2tBuNN′ ligand environment are seen, al-
though the slight broadening of the resonances assigned
to the CH2Ar protons at 3.30 and 4.16 ppm indicate a
fluxional process at room temperature. Indeed, on
cooling of the NMR sample, a partial decoalescence of
some of the ligand resonances is seen, most notably for
78.1(2)
97.9(2)
149.2(2)
138.8(2)
77.3(2)
74.6(2)
67.8(2)
72.5(2)
133.6(2)
84.0(2)
84.4(2)
146.9(2)
81.3(2)
107.40(8)
139.6(6)
147.2(5)
The six-coordinate structure of 2 is typical of the
majority of complexes reported to date (and several
herein) with O2RNN′ ligands and their homologues . The
complex possesses approximate Cs symmetry with the
pyridine ligand lying trans to the pyridyl nitrogen of
O2tBuNN′. The Sc-donor atom distances are within the
expected ranges.21,22 As is usual, the phenoxy ligand
aromatic rings are slightly “bent back” from the pyridine
ligand site. This geometric feature, and the fact that
the steric bulk of the ring ortho tert-butyl substituents
is orientated in an axial direction (broadly in line with
(21) Allen, F. H.; Kennard, O. Chem. Des. Automat. News 1993, 8,
1 and 31.
(22) Fletcher, D. A.; McMeeking, R. F.; Parkin, D. J. Chem. Inf.
Comput. Sci. 1996, 36, 746.
(23) Daitch, C. E.; Hampton, P. D.; Duesler, E. N. Inorg. Chem. 1995,
34, 5641.
(24) Evans, W. J.; Fujimoto, C. H.; Ziller, J. W. Chem. Commun.
1999, 311.

Diamino-bis(phenolate) Ti, Sc, and Y Complexes
Organometallics, Vol. 24, No. 2, 2005 313
these CH2Ar proton resonances. However, this fluxional
process could not be “frozen out” even at -80 °C, so the
room-temperature data are reported here. Assuming
that a dimeric structure is maintained in solution, the
fluxional process appears to involve aryloxide ring
exchange via overall net rotation around the Y(1)‚‚‚Y(2)
vector.
fluxional (apparent rotation about the M‚‚‚‚C(Ph)N2
vector) on the NMR time scale at room temperature.5
Compounds 7 and 8 are also fluxional at room
temperature on the NMR time scale. Thus the O2RNN′
ligand subspectra indicate apparent molecular Cs sym-
metry and the two SiMe3 groups of the PhC(NSiMe3)2
ligands appear as single resonances (integrating as 18
H with respect to those of O2RNN′), which are broad for
7 and sharp for 8. This is not consistent with the
structures proposed in eq 2, which place the SiMe3
groups in different environments. Cooling dichlo-
romethane-d2 solutions of 7 and 8 causes the fluxional
process (apparent rotation about the M‚‚‚‚C(Ph)N2 vec-
tor that exchanges the SiMe3 groups) to be frozen out.
Such fluxional behavior is characteristic of many benz-
amidinate complexes, and sometimes it can never be
frozen out on the NMR time scale.27 Free energies of
Halide substitution reactions of 2 or 4 with a range
of lithium or magnesium alkyls or LiN(SiMe3)2 were
unsuccessful. The most promising of these was the
reaction of 2 with LiCH2SiMe3, which appeared to form
Sc(O2tBuNN′)(CH2SiMe3)(py), but this product degraded
with further handling/workup and could not be obtained
in pure form. However, well-defined alkyls were readily
obtained through the protonolysis reactions summarized
in eq 1. Thus reaction of H2O2tBuNN′ with M(CH2-
SiMe3)3(THF)2 in THF (-78 °C) or benzene (7 °C)
afforded the six-coordinate compounds M(O2tBuNN′)-
(CH2SiMe3)(THF) (M ) Sc (5) or Y (6)) in 63 and 77%
yield, respectively. Attempts to recrystallize 6 were
problematic, and although this compound is spectro-
scopically pure, the %C by elemental analysis was
repeatedly low. Treatment of [ScPh3(THF)2]25 with 1
equiv of H2O2tBuNN′ yielded a complex mixture of
products that quickly decomposed in solution even in
activation at the coalescence temperatures Tc (∆Gq
)
Tc
were estimated from the variable-temperature 1H NMR
spectra using standard procedures:28,29 For 7 (Tc ) 281
( 1 K) ∆Gq281 ) 55.1 ( 0.3 kJ mol-1 and for 8 (Tc ) 210
K) ∆Gq
) 41.0 ( 1.0 kJ mol-1. Activation energies
210
obtained from coalescence temperature measurements
cannot be directly compared, however, because of the
∆Sq contribution (∆Gq ) ∆Hq - T∆Sq). Thus an analysis
of the SiMe3 line widths for 7 at six temperatures in
the range 243-263 K yielded exchange rate constants,
which were fitted to an Eyring plot,28 yielding ∆Hq )
54.2 ( 0.6 kJ mol-1 and ∆Sq ) 6.6 ( 2.0 J mol-1 K-1
.
From these data ∆Gq210 (i.e., calculated at the Tc for 8)
for 7 was found to be 52.8 ( 0.9 kJ mol-1, some ca. 12
( 2 kJ mol-1 higher than that for 8 (∆Gq
) 41.0 (
210
1.0 kJ mol-1). We attribute the higher ∆Gq for 7 to the
greater steric impedance imposed by the O2tBuNN′
ligand ortho tert-butyl groups. The small magnitude of
∆Sq is consistent with a nondissociative fluxional pro-
cess.
1
the absence of light. H NMR NOE experiments con-
clusively supported the isomers shown in eq 1 (CH2-
SiMe3 cis to both pyridyl and THF). In this regard the
compounds 5 and 6 are valence isoelectronic with the
isolated zirconium cations [Zr(O2tBuNN′)(CH2Ph)(THF)]+
reported by us previously.7
Titanium Bis(dimethylamide), Dichloride, and
Dimethyl Compounds. The synthesis and some reac-
t
tions of the compounds Ti(O2RNN′)Cl2 (R ) Bu (9) or
Me (10)), Ti(O2RNN′)(NMe2)2 (R ) tBu (11) or Me (12)),
and Ti(O2RNN′)(NMe2)(S-4-C6H4Me) (13) are summa-
rized in Scheme 2.
The most convenient syntheses of the dichloride
compounds 9 and 10 are by the sequential addition of
MeLi (2 equiv) and then H2O2RNN′ to TiCl4(THF)2 in
diethyl ether at -40 °C. After crystallization the target
compounds are obtained in 65-70% yield. This reaction
proceeds through protonolysis of the presumed inter-
R
mediate TiMe2Cl2(L)2 (L ) Et2O or THF)30 by H2O2
-
NN′ (i.e., elimination of methane) A similar method for
making 9 starting from Ti(NMe2)2Cl2 and H2O2tBuNN′
(i.e., elimination of HNMe2) has also been employed
N,N′-Bis(trimethylsilyl)benzamidinate scandium com-
t
plexes Sc(O2RNN′){PhC(NSiMe3)2} (R ) Bu (7) or Me
(8)) were prepared according to the one-pot reactions
shown in eq 2 in ca. 40% recrystallized yields. Direct
treatment of Sc(O2tBuNN′)Cl(py) (2) with Li[PhC(N-
SiMe3)2], although promising on the NMR tube scale,
did not scale-up cleanly. Group 3 benzamidinate com-
plexes have been studied in detail by Teuben, Arnold,
and others.26 We have reported the related structurally
characterized diamino-diamide complexes M(N2NN′)-
{PhC(NSiMe3)2} (M ) Sc or Y), which were found to be
(26) See for example: Duchateau, R.; van Wee, C. T.; Meetsma, A.;
van Duijnen, P. T.; Teuben, J. H. Organometallics 1996, 15, 2279.
Duchateau, R.; Meetsma, A.; Teuben, J. H. Organometallics 1996, 15,
1656. Bambirra, S.; Brandsma, M. J. R.; Brussee, E. A. C.; Meetsma,
A.; Hessen, B.; Teuben, J. H. Organometallics 2000, 19, 3197. Edel-
mann, F. T.; Richter, J. Eur. J. Solid State Inorg. Chem. 1996, 33,
157. Hagedorn, J. R.; Arnold, J. Organometallics 1996, 15, 984.
(27) See the following and references therein: Stewart, P. J.; Blake,
A. J.; Mountford, P. Inorg. Chem. 1997, 36, 1982. Stewart, P. J.; Blake,
A. J.; Mountford, P. Inorg. Chem. 1997, 36, 3616.
(28) Sandstro¨m, J. Dynamic NMR Spectroscopy; Academic Press:
London, 1992.
(29) Green, M. L. H.; Wong, L.-L.; Sella, A. Organometallics 1992,
11, 2660.
(30) Duncan, D.; Livinghouse, T. Organometallics 1999, 18, 4421.
(25) Putzer, M. A.; Bartholomew, G. P. Z. Anorg. Allg. Chem. 1999,
625, 1777.

314 Organometallics, Vol. 24, No. 2, 2005
Scheme 2. Synthesis and Reactions of Dichloride and Dimethylamide Complexes
Boyd et al.
(46% isolated yield). It was also shown on an NMR tube
In both compounds the Ti-Cl bonds trans to phenoxide
are significantly longer than those trans to the tertiary
amine nitrogens, consistent with the respective trans
influences. Interestingly, the solid state structure of Zr-
(O2tBuNN′)Cl27 has a trans disposition of the phenoxide
rings in the solid state. However, the NMR data show
tBu
scale that reaction of Me3SiCl (2 equiv) with Ti(O2
-
NN′)(NMe2)2 (11) in benzene-d6 gives 9 and Me3SiNMe2
as a side-product after 3 days in quantitative yield. The
route to 9 and 10 via TiMe2Cl2(L)2 parallels that used
by us7 for the congeners Zr(O2RNN′)Cl2 starting from
H2O2RNN′ and Zr(CH2SiMe3)2Cl2(Et2O)2 with the elimi-
nation of 2 equiv of SiMe4. Protonolysis methodology
also allow the synthesis of the bis(dimethylamide)
derivatives 11 and 12 via the smooth reaction of
Ti(NMe2)4 and H2O2RNN′, affording the desired com-
pounds in ca. 80-90% yield. The solid state structures
of 9, 10, and 11 have been determined and are shown
in Figures 4-6; selected distances and angles are
summarized in Tables 4-6.
that in solution this compound exists as a mixture of
Me
cis (C1) and trans (Cs) isomers in a 65:35 ratio. Zr(O2
-
NN′)Cl2 also exists as two isomers in solution but with
a cis:trans ratio of 95:5. The NMR spectra of 9 and 10
are consistent with the solid state structures but show
evidence for the presence of a small amount of a second,
C2 symmetric, species in the ratios 92 (C1):8 and 95:5,
respectively. The signals for the two isomers in each
case are sharp up to 90 °C in toluene-d8. This contrasts
with the zirconium systems, which are fluxional and
undergo intramolecular cis/trans interconversion at
ambient temperature. The activation parameters for the
exchange process for Zr(O2tBuNN′)Cl2 suggested a very
t
The molecular structures of Ti(O2RNN′)Cl2 (R ) Bu
(9) or Me (10)) are similar, featuring approximately
octahedral coordination at titanium and mutually cis
chloride and phenoxide ligands. The overall symmetry
is C1, and the cis arrangement of the phenoxy groups
contrasts their arrangement in all of the other struc-
tures described herein, but are analogous to that found
in the solid state for Zr(O2MeNN′)Cl2.7 The metric
parameters for 9 and 10 are within the expected
ranges.21,22 Most of the titanium-donor atom distances
in the more sterically crowded 9 are slightly longer than
their counterparts in 10, but this is only a small effect.
ordered transition state (∆Sq ) -102(5) J mol-1 K-1
)
consistent with a nondissociative exchange mechanism.
The nonfluxional nature of 9 and 10 would be consistent
with this since the atomic radius of titanium is smaller
than that of zirconium, making nondissociative rear-
rangement a higher energy process.
The molecular structure of Ti(O2tBuNN′)(NMe2)2 (11)
shown in Figure 6 shows a trans arrangement of the

Diamino-bis(phenolate) Ti, Sc, and Y Complexes
Organometallics, Vol. 24, No. 2, 2005 315
Figure 4. Displacement ellipsoid plot (20% probability) of Ti(O2tBuNN′)Cl2‚0.5CH2Cl2 (9‚0.5CH2Cl2). H atoms and CH2Cl2
molecule of crystallization omitted for clarity.
Ti(1)-N(4) bond length of Ti(1)-N(3) may be traced to
increased steric repulsion in the apical position (between
the NMe2 ligand and the pyridyl ortho hydrogen and
the phenoxide ring ortho tert-butyl groups).
In addition to the reaction of 11 with Me3SiCl (2
equiv) to yield Ti(O2tBuNN′)Cl2 (9) several protonolysis
reactions were investigated with phenols, thiols, and
primary amines. Of those attempted, only the reaction
with HS-4-C6H4Me yielded a clean product, namely, Ti-
(O2tBuNN′)(NMe2)(S-4-C6H4Me) (13, Scheme 2), which
was isolated in 52% yield as a yellow-brown powder.
Reaction of 11 with 2 equiv of the thiophenol did not
lead to replacement of more than the one NMe2 ligand.
The apical location of the S-4-C6H4Me ligand in 13 was
1
Figure 5. Displacement ellipsoid plot (20% probability)
of Ti(O2MeNN′)Cl2‚2.5C6H6 (10‚2.5C6H6). H atoms and C6H6
molecules of crystallization omitted for clarity.
established by a H NMR NOE experiment. It is not
unreasonable to rationalize the exclusive substitution
of the apical NMe2 ligand on the basis of the structural
data, which suggest that this is the more weakly bound
NMe2 ligand and presumably has the more basic
nitrogen atom (longest Ti-NMe2 bond and therefore the
most polar).
phenoxide rings and mutually cis NMe2 ligands. The
NMR data for 11 and 12 are entirely consistent and
show no evidence for other isomers. Overall the bond
lengths and angles for 11 are as expected.21,22 Interest-
ingly, the difference (0.013(4) Å) between the two Ti-
Namide bond lengths is at the margins of statistical
significance but suggests that the Ti(1)-N(3) bond is
genuinely the shorter of the two. The difference (0.004-
(4) Å) between the Ti-Npyridyl and Ti-Namine bond
lengths is, however, not significant. The sums of the
angles subtended at the NMe2 nitrogens are ca. 360°,
showing that these are sp2 hybridized and formally each
able to act as three-electron donors (σ + π) to the metal
center. For maximum π donation from the NMe2 nitro-
gens to titanium the 2pπ lone pairs should overlap with
orthogonal “t2g” type dπ acceptor orbitals (in Figure 6
these would be the dxz and dyz orbitals if the local z axis
is defined as the Ti(1)‚‚‚N(4) vector). Therefore the
dihedral angle C(40)-N(4)-Ti(1)-N(3) should ideally
be 0° to achieve maximum N(pπ)-Ti(dπ) overlap, whereas
in 11 this angle is 38.7°. It is likely that steric repulsions
between the methyl group of C(39) and the pyridyl ortho
H atom (bonded to C(36)) prevent the optimum ar-
rangement of the two NMe2 ligands. The slightly longer
We were particularly interested in preparing titanium
dimethyl derivatives because of their importance as
R
polymerization catalyst precursors. Reaction of Ti(O2
-
NN′)Cl2 (9, 10) with 2 equiv of MeMgBr in benzene or
toluene gave modest yields of the corresponding di-
methyls Ti(O2R)Me2 (R ) tBu (14) or Me (15), eq 3). The
NMR spectra for the new compounds are consistent with
the Cs symmetric structures illustrated and possess two
inequivalent Ti-Me ligands. No evidence for alternative
C1 symmetric isomers was found by NMR. Attempts to

316 Organometallics, Vol. 24, No. 2, 2005
Boyd et al.
Figure 6. Displacement ellipsoid plot (25% probability) of Ti(O2tBuNN′)(NMe2)2 (11). H atoms omitted for clarity.
obtain diffraction-quality crystals of either compound
were unsuccessful. The structures of well-defined mono-
methyl cations derived from 14 and 15 are described
later in this contribution.
Synthesis and Structures of Imidotitanium Com-
plexes. Over recent years we and others have described
the synthesis of a number of classes of imidotitanium
complexes and their reactions with unsaturated sub-
strates. Aryloxide-supported group 4 imido derivatives
were first prepared by Rothwell and co-workers.31 We
have reported on the structures and bonding of imidoti-
tanium compounds with monodentate aryloxide ligands,
focusing on how the nuclearity and coordination number
can be fine-tuned by aryloxide O- and imido N-substit-
uents.32 Of particular relevance to this present contri-
bution is our recent work with calix[4]arene-supported
imidotitanium complexes33 which undergo imido group
transfer and/or coupling reactions with CO2 and other
heterocumulenes. We were interested to explore the
structures and reactivity of titanium imido complexes
supported by O2RNN′ and a related monoamino-bis-
(phenoxide) ligand. As a benchmark unsaturated sub-
strate we chose CO2, which has been shown previously
to have a varied reaction chemistry with TidNR bonds
depending on the identity of the supporting ligand set
and the imido N-R substituent itself.33-35
Figure 7. Displacement ellipsoid plot (25% probability)
of Ti(O2tBuNN′)(NtBu)(py)‚2C6H6 (16‚2C6H6). H atoms omit-
ted for clarity.
Attempts to prepare homologues with the O2MeNN′
ligand were unsuccessful. The new compounds 16 and
17 were isolated by crystallization from benzene/pen-
tane in 48 and 80% yield, respectively. The NMR spectra
were consistent with the six-coordinate Cs symmetric
structures shown in Scheme 3. The X-ray molecular
structure of 16 confirms the proposed structures (Figure
7), and selected bond lengths and angles are presented
in Table 7. A second method for the synthesis of 17 by
way of tert-butylimide/arylamine exchange was also
investigated. Treatment of a solution of 16 in benzene-
d6 with 1 equiv of 2,6-dimethylaniline gave 17 and tert-
butyaniline in quantitative yield after 6 days at 80 °C.
However, due to the efficiency of the direct synthesis of
17 from Na2O2tBuNN′ and Ti(N-2,6-C6H3Me2)Cl2(py)3,
tert-Butyl- and aryl-imido titanium compounds can
show markedly different reactions with CO2.35 Thus the
two new compounds Ti(O2tBuNN′)(NR)(py) (R ) tBu (16)
or 2,6-C6H3Me2 (17)) were prepared from Na2O2tBuNN′
36
and the corresponding Ti(NR)Cl2(py)3 (Scheme 3).
(31) Zambrano, C. H.; Profilet, R. D.; Hill, J. E.; Fanwick, P. E.;
Rothwell, I. P. Polyhedron 1993, 12, 689l. Hill, J. E.; Fanwick, P. E.;
Rothwell, I. P. Inorg. Chem. 1991, 30, 1143.
(32) Collier, P. E.; Blake, A. J.; Mountford, P. J. Chem. Soc., Dalton
Trans. 1997, 2911.
(33) Dubberley, S. R.; Friedrich, A.; Willman, D. A.; Mountford, P.;
Radius, U. Chem. Eur. J. 2003, 9, 3634.
(34) Blake, A. J.; McInnes, J. M.; Mountford, P.; Nikonov, G. I.;
Swallow, D.; Watkin, D. J. J. Chem. Soc., Dalton Trans. 1999, 379
(35) Guiducci, A. E.; Cowley, A. R.; Skinner, M. E. G.; Mountford,
P. J. Chem. Soc., Dalton Trans. 2001, 1392.
(36) Blake, A. J.; Collier, P. E.; Dunn, S. C.; Li, W.-S.; Mountford,
P.; Shishkin, O. V. J. Chem. Soc., Dalton Trans. 1997, 1549.

Diamino-bis(phenolate) Ti, Sc, and Y Complexes
Organometallics, Vol. 24, No. 2, 2005 317
Scheme 3. Synthesis and Reactions of Imidotitanium Complexes
Table 4. Selected Bond Lengths (Å) and Angles
Table 6. Selected Bond Lengths (Å) and Angles
(deg) for Ti(O2tBuNN′)Cl2 (9)
(deg) for Ti(O2tBuNN′)(NMe2)2 (11)
Ti(1)-Cl(1)
Ti(1)-O(1)
Ti(1)-N(1)
2.3929(12)
1.807(3)
2.260(3)
Ti(1)-Cl(2)
Ti(1)-O(2)
Ti(1)-N(2)
2.2840(12)
1.843(3)
2.119(3)
Ti(1)-O(1)
Ti(1)-N(1)
Ti(1)-N(3)
1.909(2)
2.338(3)
1.927(3)
Ti(1)-O(2)
Ti(1)-N(2)
Ti(1)-N(4)
1.927(2)
2.342 (3)
1.940(3)
Cl(1)-Ti(1)-Cl(2)
90.96(4)
Cl(1)-Ti(1)-N(1)
Cl(1)-Ti(1)-N(2)
N(1)-Ti(1)-N(2)
85.15(9)
80.23(9)
75.75(12)
N(1)-Ti(1)-N(2)
N(2)-Ti(1)-N(3)
N(2)-Ti(1)-N(4)
N(1)-Ti(1)-O(1)
N(3)-Ti(1)-O(1)
N(1)-Ti(1)-O(2)
N(3)-Ti(1)-O(2)
O(1)-Ti(1)-O(2)
72.5(1)
N(1)-Ti(1)-N(3) 165.84(11)
Cl(2)-Ti(1)-N(1) 174.51(9)
95.91(11) N(1)-Ti(1)-N(4)
164.43(11) N(3)-Ti(1)-N(4)
92.52(12)
99.53(13)
79.20(9)
96.81(11)
84.0(1)
Cl(2)-Ti(1)-N(2)
Cl(1)-Ti(1)-O(1)
N(1)-Ti(1)-O(1)
99.8(1)
95.9(1)
Cl(2)-Ti(1)-O(1) 101.59(9)
88.7(1)
N(2)-Ti(1)-O(1)
82.71(12) N(2)-Ti(1)-O(1)
158.34(13)
96.59(9)
82.78(13)
97.14(11) N(4)-Ti(1)-O(1)
80.6(1) N(2)-Ti(1)-O(2)
90.37(11) N(4)-Ti(1)-O(2)
162.2(1)
Cl(1)-Ti(1)-O(2) 162.4(1)
Cl(2)-Ti(1)-O(2)
86.11(12) N(2)-Ti(1)-O(2)
143.2(2)
N(1)-Ti(1)-O(2)
Ti(1)-O(1)-C(1)
97.79(11)
Ti(1)-O(2)-C(15) 136.3(2)
Ti(1)-O(1)-C(1) 143.2(2)
Ti(1)-O(2)-C(15) 136.3(2)
Table 5. Selected Bond Lengths (Å) and Angles
(deg) for Ti(O2MeNN′)Cl2 (10)
Table 7. Selected Bond Lengths (Å) and Angles
(deg) for Ti(O2tBuNN′)(NtBu)(py) (16)
Ti(1)-Cl(1)
Ti(1)-N(1)
Ti(1)-O(1)
2.306(2)
2.212(5)
1.844(4)
Ti(1)-Cl(2)
Ti(1)-N(2)
Ti(1)-O(2)
2.372(2)
2.277(5)
1.812(4)
Ti(1)-O(1)
Ti(1)-N(1)
Ti(1)-N(3)
1.965(2)
2.230(2)
1.719(2)
Ti(1)-O(2)
Ti(1)-N(2)
Ti(1)-N(4)
1.976(2)
2.442(2)
2.254 (2)
Cl(1)-Ti(1)-Cl(2)
Cl(2)-Ti(1)-N(1)
Cl(2)-Ti(1)-N(2)
Cl(1)-Ti(1)-O(1)
N(1)-Ti(1)-O(1)
Cl(1)-Ti(1)-O(2)
N(1)-Ti(1)-O(2)
O(1)-Ti(1)-O(2)
Ti(1)-O(1)-C(1)
92.59(8)
Cl(1)-Ti(1)-N(1)
Cl(1)-Ti(1)-N(2)
N(1)-Ti(1)-N(2)
Cl(2)-Ti(1)-O(1)
N(2)-Ti(1)-O(1)
Cl(2)-Ti(1)-O(2)
N(2)-Ti(1)-O(2)
Ti(1)-N(1)-C(20)
Ti(1)-O(2)-C(10)
95.8(1)
82.7(1)
85.6(1)
94.8(1)
81.6(2)
105.0(1)
159.2(2)
98.3(2)
133.8(4)
171.4(1)
75.7(2)
163.3(1)
84.9(2)
94.2(1)
83.5(2)
116.8(4)
142.5(4)
N(1)-Ti(1)-N(2)
73.11(9)
N(1)-Ti(1)-N(3)
102.44(11)
162.6(1)
94.39(11)
80.15(8)
88.0(1)
81.89(8)
87.3(1)
N(2)-Ti(1)-N(3) 175.43(11) N(1)-Ti(1)-N(4)
N(2)-Ti(1)-N(4)
90.12(9)
93.40(9)
N(3)-Ti(1)-N(4)
N(2)-Ti(1)-O(1)
N(1)-Ti(1)-O(1)
N(3)-Ti(1)-O(1)
99.30(11) N(4)-Ti(1)-O(1)
N(1)-Ti(1)-O(2)
85.92(9)
N(2)-Ti(1)-O(2)
N(3)-Ti(1)-O(2)
98.98(11) N(4)-Ti(1)-O(2)
O(1)-Ti(1)-O(2) 161.41(9)
Ti(1)-O(1)-C(1) 139.9(2)
Ti(1)-N(3)-C(37) 171.5(2)
Ti(1)-O(2)-C(15) 134.5(2)
this exchange route was not repeated on a preparative
scale.
that the N(3)-Ti(1)-donor-atom angles are all greater
than 95-100° is typical for six-coordinate imido com-
plexes.21,22,36 The titanium to pyridyl (N(1)) and pyridine
The molecular structure of 16 features bond lengths
and angles within the usual ranges.21,22 The observation

318 Organometallics, Vol. 24, No. 2, 2005
Boyd et al.
Figure 8. Displacement ellipsoid plot (35% probability) of Ti2(O2tBuNN′)2(µ-O)2‚3CH2Cl2 (18‚3CH2Cl2). H atoms and CH2-
Cl2 molecules of crystallization omitted for clarity.
Table 8. Selected Bond Lengths (Å) and Angles
in this area we propose that the formation of 18
proceeds via CO2 cycloaddition to the TidNR linkages
of 16 or 17, yielding N,O-bound carbamate products of
the type Ti(O2tBuNN′){NRC(O)O} (not observed). These
then subsequently extrude (by cycloreversion) RNCO.
(deg) for Ti2(O2tBuNN′)2(µ-O)2 (18)
Ti(1)-O(1)
Ti(1)-N(1)
Ti(1)-O(3)
1.921(2)
2.299(3)
1.776(2)
Ti(1)-O(2)
Ti(1)-N(2)
Ti(1)-O(3A)
1.894(2)
2.231(3)
1.965(2)
O(3)-Ti(1)-O(3A)
Ti(1)-O(1)-C(1)
O(1)-Ti(1)-O(2)
O(2)-Ti(1)-O(3)
O(2)-Ti(1)-O(3A)
O(1)-Ti(1)-N(1)
O(3)-Ti(1)-N(1)
O(1)-Ti(1)-N(2)
O(3)-Ti(1)-N(2)
82.91(11) Ti(1)-O(3)-Ti(1A)
97.09(11)
In general terms the Ti2(µ-O)2 core of 18 (Figure 8) is
well-established in the structural chemistry of tita-
nium.21,22 Notably, however, there is a pronounced
asymmetry as manifested by rather different Ti-O
distances of 1.776(2) (trans to tertiary amine N) and
1.965(2) Å (trans to aryloxide O), which may be at-
tributed in part to the differing trans labilizing ability
of the respective donors opposite the Ti-O bonds. The
difference (∆Ti-O ) 0.189(4) Å) between the Ti-O bond
distances is, however, much larger than that between
the two Ti-Cl distances in the monomeric dichlorides
9 (∆Ti-Cl ) 0.109(2) Å) and 10 (∆Ti-Cl ) 0.066(4) Å),
which also have either an aryloxide O or tertiary amine
N trans to the individual Ti-Cl bonds. Therefore the
extreme differential lengthening of the Ti-O bonds in
18 is probably also due to steric repulsion between the
neighboring O2tBuNN′ ligands of the two Ti atoms.
134.0(2)
94.2(1)
Ti(1)-O(2)-C(16) 134.9(2)
O(1)-Ti(1)-O(3)
106.51(11) O(1)-Ti(1)-O(3A) 163.9(1)
105.3(1)
96.7(1)
85.3(1)
162.6(1)
81.9(1)
94.4(1)
N(1)-Ti(1)-N(2)
O(2)-Ti(1)-N(1)
O(3A)-Ti(1)-N(1)
O(2)-Ti(1)-N(2)
O(3A)-Ti(1)-N(2)
73.1(1)
86.1(1)
83.68(9)
159.0(1)
83.6(1)
(N(4)) distances are rather similar, but the trans (to Nt-
Bu) coordinated amino nitrogen N(2) has a much longer
bond length to titanium, consistent with the well-known
trans influence of imido ligands.37 The imido ligand in
16 acts as a four-electron donor (1 σ and 2 π orbital
interactions) being essentially sp-hybridized (Ti(1)-
N(3)-C(37) ) 171.5(2)°). The six-coordination of 16 is
rather unusual in the sense that all previously reported
bis(aryloxide) imidotitanium compounds have been
either five- or four-coordinate, but presumably this is a
simple consequence of the chelating tetradentate nature
of O2tBuNN′.
The reactions of Ti(NR)(O2tBuNN′)(py) (16 or 17) with
CO2 (1 atm) were assessed by NMR tube scale experi-
ments. In each case the corresponding isocyanate RNCO
was formed quantitatively within 1 h along with the
µ-oxo-bridged dimer Ti2(O2tBuNN′)2(µ-O)2 (18) and free
pyridine. The compound 18 was most easily made on a
preparative scale by the carefully controlled hydrolysis
of 16. The X-ray molecular structure of 18 is shown in
Figure 8, and selected bond lengths and angles are listed
in Table 8. The NMR data for 18 are consistent with
the solid state structure. On the basis of the literature
Apart from those associated with the Ti2(µ-O)2 unit,
the distances and angles around the Ti centers are
within the expected ranges.21,22 Note, however, that the
overall dimeric structure of 18 is rather different from
tBu
those of Sc2(O2MeNN′)2Cl2 (3, Figure 2) and Y2(O2
-
NN′)2(µ-Cl)2(py)2 (4, Figure 3). In both 3 and 4 the
aryloxide donors within each O2RNN′ ligand adopt a
mutually trans disposition, whereas in 18 they are
mutually cis, just as in the dichlorides 9 and 10. It is
possible that in 18 the cis arrangement is chosen to
reduce the degree of repulsion between the neighboring
O2tBuNN′ ligands. In 3 the O2MeNN′ ligands do not bear
the bulky ortho tert-butyl groups, and in 4 there is a
greater separation of the neighboring O2tBuNN′ ligands
due to the longer Y-Cl bonds. Other factors may also
be important in setting the overall geometry of 18 and
the other two dimers, but those highlighted here are
(37) See the following and references therein: Kaltsoyannis, N.;
Mountford, P. J. Chem. Soc., Dalton Trans. 1999, 781.

Diamino-bis(phenolate) Ti, Sc, and Y Complexes
Organometallics, Vol. 24, No. 2, 2005 319
Figure 9. Displacement ellipsoid plot (25% probability) of Ti(O2tBuN)(N-2,6-C6H3Me2)(py)‚0.5C6H6 (20‚0.5C6H6). H atoms
and benzene molecule of crystallization omitted for clarity.
undoubtedly important. The three compounds 3, 4, and
18 exemplify the subtle structural variations that can
be anticipated for O2RNN′ and related ligands.
O2tBuN tertiary amine N and pyridine N atoms occupy-
ing the axial positions. In general terms this geometry
is typical of five-coordinate imido-titanium (and -zirco-
nium) bis(aryloxide) complexes.31 The bond distances
and angles at the two metal centers are unexceptional
for this class of compound.21,22 The Ti-Namine and Ti-O
distances are all shorter for 20 and 21 in comparison
with those for six-coordinate Ti(O2tBuNN′)(NtBu)(py)
(16), whereas the TidNimide distances are longer by
0.016(3) and 0.003(3) Å, respectively. Only the first bond
length difference is statistically significant, but in
general one should expect shorter TidNimide distances
for tert-butyl imido than for aryl-imido ligands.37 It is
also usually found that tert-butyl imido ligands have a
greater bond lengthening effect on the other ligands
present. Notwithstanding these specific imido ligand
effects, the increased coordination number for 16 should
lead to a general increase in metal-ligand bond lengths
as compared to 20 and 21.
A more detailed comparison of the molecular struc-
tures of 20 and 21 shows that they differ significantly
in the conformations of the six-membered chelate rings.
The overall effect is to invert the geometry at the O2tBuN
amino nitrogen N(1) such that the n-propyl substituent
is syn with respect to TidNimide in 20 and anti with
respect to TidNimide in 21. We believe that these two
differing conformations correspond to the two isomers
present in solution and that by good fortune we have
obtained the complimentary isomers in the solid state.
The two different conformations lead to rather different
distances and angles at the two Ti centers. In particular,
the Ti-N distances for 20 are all longer than those in
21 despite the presence of the more sterically demand-
ing imido N-substituent in the latter compound. In
addition, the two Ti-O distances in 20 are very different
(∆Ti-O ) 0.026(2) Å), whereas in 21 they are experi-
mentally identical (∆Ti-O ) 0.002(2) Å). The two
aryloxide rings in 21 are related by a molecular plane
of symmetry, whereas in 20 they are not. This difference
We now return again to the reactions with CO2.
Although cycloreversion reactions of first-formed car-
bamates to form oxotitanium compounds and isocyan-
ates are well-established in the reactions of imidotita-
nium compounds with CO2,33-35 it is rather unusual not
to observe the initial formation of a carbamate inter-
mediate, especially for aryl imides. We speculated that
the tetradentate nature of O2tBuNN′ might lead to a
rather crowded six-coordinate carbamate intermediate
and that steric repulsions might promote the extrusion/
cycloreversion reaction. We therefore targeted imidoti-
tanium complexes of the tridentate ligand O2tBuN (Chart
1) as shown in Scheme 3.
Reaction of Na2O2tBuN with Ti(NR)Cl2(py)3 (R ) tBu,
i
2,6-C6H3Me2 or 2,6-C6H3 Pr2) afforded the corresponding
five-coordinate complexes Ti(NR)(O2tBuN)(py) (19, 20,
and 21) in 3%, 45%, and 21% yields, respectively. Due
to the very low yield of Ti(NtBu)(O2tBuN)(py) (19) and
difficulties in obtaining an analytically pure sample, this
1
compound was characterized by H NMR spectroscopy
only. All three compounds exist as a mixture of two
isomers in solution (ratios between the isomers are
between 3:2 and 3:1). Both isomers have overall Cs
symmetry on the NMR time scale, with pyridine and
O2tBuNN′ ligands present in a 1:1 ratio. In no case was
it possible to separate the two isomers by fractional
crystallization on the bulk scale. The ratio of the isomers
does not change with time or temperature. Nonetheless
for both Ti(N-2,6-C6H3Me2)(O2tBuN)(py) (20) and Ti(N-
i
2,6-C6H3 Pr2)(O2tBuN)(py) (21) we were able to grow a
small number of diffraction-quality crystals, and the
molecular structures and selected bond lengths and
angles are shown in Figures 9 and 10 and in Tables 9
and 10.
Molecules of both 20 and 21 possess approximately
trigonal bipyramidal titanium centers. The imido N and
aryloxide O atoms define the equatorial plane, and the

320 Organometallics, Vol. 24, No. 2, 2005
Boyd et al.
i
Figure 10. Displacement ellipsoid plot (25% probability) of Ti(O2tBuN)(N-2,6-C6H3 Pr2)(py) (21). H atoms omitted for clarity.
Table 9. Selected Bond Lengths (Å) and Angles
(deg) for Ti(O2tBuN)(N-2,6-C6H3Me2)(py) (20)
or Me; X ) Cl, Me, or CH2Ph) we found that activation
with either MAO or B(ArF)3 gave very poorly active
catalysts. This was rationalized in terms of the unavoid-
able dilution effect when moving from a neat liquid
monomer as the polymerization medium (as used in
Kol’s work) to toluene and a gaseous monomer. Indeed,
it has been shown that the 1-hexene polymerization
activity of the Zr(O2RNN′)X2/B(ArF)3 catalyst system
decreases from 5700 g mmol-1 h-1 in neat 1-hexene to
650 g mmol-1 h-1 on dilution to 30% 1-hexene in
heptane.11
Ti(1)-N(1)
Ti(1)-N(2)
Ti(1)-N(3)
2.2267(15)
1.7349(15)
2.2247(16)
Ti(1)-O(1)
Ti(1)-O(2)
1.8862(12)
1.9118(12)
O(1)-Ti(1)-O(2)
O(1)-Ti(1)-N(1)
O(2)-Ti(1)-N(1)
O(1)-Ti(1)-N(2)
O(2)-Ti(1)-N(2)
121.19(6)
85.34(5)
83.87(5)
118.58(6)
119.99(6)
N(1)-Ti(1)-N(2)
O(1)-Ti(1)-N(3)
O(2)-Ti(1)-N(3)
N(1)-Ti(1)-N(3)
N(2)-Ti(1)-N(3)
96.14(6)
96.16(5)
84.13(5)
166.17(6)
94.66(6)
Table 10. Selected Bond Lengths (Å) and Angles
i
(deg) for Ti(O2tBuN)(N-2,6-C6H3 Pr2)(py) (21)
We evaluated the ethylene polymerization activity of
the six compounds Ti(O2RNN′)X2 (R ) Bu or Me; X )
t
Ti(1)-N(1)
Ti(1)-N(2)
Ti(1)-N(3)
2.2199(17)
1.7218(18)
2.2054(17)
Ti(1)-O(1)
Ti(1)-O(2)
1.8961(14)
1.8984(14)
Cl, NMe2, or Me) in the presence of MAO cocatalyst (Ti:
Al ratio ) 1:1500; toluene solvent; 5 bar ethylene). Very
low polymerization activities of between 0.9 and 8.9 g
mmol-1 h-1 bar-1 were recorded. Under identical condi-
tions, CpzZrCl2 afforded an activity of 1480 g mmol-1
h-1 bar-1. The activities for the O2MeNN′-supported
O(1)-Ti(1)-O(2)
O(1)-Ti(1)-N(1)
O(2)-Ti(1)-N(1)
O(1)-Ti(1)-N(2)
O(2)-Ti(1)-N(2)
131.63(7)
83.65(6)
82.99(6)
113.31(7)
114.30(7)
N(1)-Ti(1)-N(2)
O(1)-Ti(1)-N(3)
O(2)-Ti(1)-N(3)
N(1)-Ti(1)-N(3)
N(2)-Ti(1)-N(3)
96.66(7)
91.63(6)
90.32(6)
165.85(6)
97.46(8)
systems (12, 7.8; 10, 8.9; 15, 4.8 g mmol-1 h-1 bar-1
)
were superior to those of the O2tBuNN′-supported ho-
mologues (11, 2.3; 9, 0.9; 14, 1.8 g mmol-1 h-1 bar-1).
Molecular weight distributions were broad, multimodal,
and indicative of the formation of several catalytically
active species. Even more disappointing was the absence
of any activity at all for the dimethyl compounds Ti-
is not evident in solution on the NMR time scales as
stated above.
As mentioned, we prepared the compounds 19-21 in
an attempt to control the cycloaddition/cycloreversion
reactions of CO2 at the TidNR multiple bonds. Regret-
tably, reaction of either 20 or 21 with CO2 gave rather
complex mixtures, which could not be identified. Thus
there is inherently rather different reactivity between
the systems supported by the tri- and tetradentate
ligands O2tBuN and O2tBuNN′ and also between these
and the O4-donor calixarene systems.
Polymerization Studies and Formation of Tita-
nium Monomethyl Cations Supported by O2RNN′
Ligands. As mentioned, Kol and co-workers have
shown that group 4 dibenzyl compounds supported by
diamine-bis(phenoxide) and related ligands can be pre-
catalysts for the polymerization (in some instances
living) of 1-hexene.8-14 The activity depends critically
on the metal (titanium or zirconium) and the pendant
group (“L”) of the (L)CH2N(CH2-2-O-3,5-C6H2R2)2 ligand.
In our previous evaluation7 of ethylene polymerization
by the zirconium precatalysts [Zr(O2RNN′)X2] (R ) tBu
(O2RNN′)Me2 (R ) Bu (14) or Me (15)) when activated
t
by B(ArF)3, [CPh3][B(ArF)4], or [NHMe2Ph][B(ArF)4] in
the presence of AliBu3. This behavior parallels that of
the zirconium compounds.7
To compare with Kol’s work on the B(ArF)3-activated
t
systems M{(L)CH2N(CH2-2-O-3,5-C6H2 Bu2)2}R2 (M )
Ti or Zr, R ) alkyl), we evaluated the polymerization of
1-hexene by the catalyst system Ti(O2tBuNN′)Me2/
B(ArF)3. The polymerization was very sluggish, even in
neat 1-hexene, and an activity of only 0.50 g mmol-1
h-1 was recorded. GPC analysis of the atactic poly(1-
hexene) gave Mw ) 60 400, Mn ) 24 600, and Mw/Mn )
2.5. The slightly high polydispersity index may be
attributed to a small high Mw “tail” for the polymer
(confirmed by a differential pressure chromatogram),
perhaps indicative of a second catalytically active spe-

Diamino-bis(phenolate) Ti, Sc, and Y Complexes
Organometallics, Vol. 24, No. 2, 2005 321
cies present in the mixture. Thus 14 provides a homo-
geneous and predominantly single-site polymerization
catalyst with B(ArF)3. The low polymerization activity
is entirely consistent with previous reports that polym-
erization by titanium precatalysts Ti{(L)CH2N(CH2-2-
perature was still consistent with a noncoordinated
[MeB(ArF)3]- anion.
NMR tube experiments between Ti(O2MeNN′)Me2 (15)
and either B(ArF)3 or [CPh3][B(ArF)4] in dichloro-
methane-d2 afforded an analogous monomethyl tita-
nium cation, “[Ti(O2MeNN′)Me]+”, along with noncoor-
dinated [MeB(ArF)3]- or [B(ArF)4]- anions. The spectra
for the cationic species were sharp at room temperature,
fully consistent with C1 symmetry and analogous to
those of “[Ti(O2tBuNN′)Me]+” at 183 K. Attempts to
isolate salts of “[Ti(O2MeNN′)Me]+” on a preparative
scale were unsuccessful.
t
O-3,5-C6H2 Bu2)2}(CH2Ph)2 decreases with increasing
donor ability of the “L” moiety and that activities for
titanium are orders of magnitude lower than those for
zirconium. Thus for “L” ) CH2NMe2,8 CH2OMe,9 or
THF,14 activities in the range 12-30 g mmol-1 h-1 were
reported, but for “L” ) furanyl (a less good Lewis base)13
an activity of 200 g mmol-1 h-1 was found. For the
corresponding zirconium systems,11 the 1-hexene po-
lymerization activities for “L” ) CH2NMe2 and 2-pyridyl
were 21 000 and 5700 g mmol-1 h-1
.
We were interested in characterizing the monomethyl
cation formed from Ti(O2tBuNN′)Me2 (14) and B(ArF)3.
In this context we note that Kol recently reported that
the Cs symmetric monobenzyl cation [Zr(OtBu2NN*)(CH2-
t
Ph)]+ (H2O2tBuNN* ) Me2NCH2CH2N(2-HO-3,5-C6H2 -
Bu2)2) is formed from Zr(OtBu2NN*)(CH2Ph)2 on treat-
ment with B(ArF)3.12 NMR characterization (chloro-
benzene-d5, -35 °C) showed the presence of a noncoor-
dinated [PhCH2B(ArF)3]- anion and established that the
NMe2 donor and remaining benzyl group are coordi-
nated cis to each other in the proposed five-coordinate
cation. This is consistent with our results7 for the Cs
symmetric THF adducts [Zr(OR2NN′)(CH2Ph)(THF)]+ (R
Two most likely explanations for the NMR data for
“[Ti(O2RNN′)Me]+” can be advanced. The first is that
these are five-coordinate monomeric cations with cis
coordinated aryloxide moieties in the ground state (i.e.,
rather like the dichlorides Ti(O2RNN′)Cl2 but with one
ligand removed) and which are highly fluxional for R )
tBu but rigid on the NMR time scale for R ) Me. The
second is that they are dimeric as proposed in eq 4, with
titanium centers bridged via phenoxide O atoms just
as for the isoelectronic and structurally characterized
scandium complex Sc2(O2MeNN′)2Cl2 (3, Figure 2). We
favor the second interpretation since it accounts for the
more fluxional nature of [Ti2(O2tBuNN)2Me2]2+ (more
sterically crowded O donors) and is consistent with the
clear desire of all seven of the structurally characterized
O2RNN′compounds of Sc or Ti reported herein to seek
six-coordination.
t
) Me or Bu; isolated and fully characterized as their
[PhCH2B(ArF)3]- salts), which also have the CH2Ph
ligand cis to the pyridyl donor.
Reaction of Ti(O2tBuNN′)Me2 (14) with B(ArF)3 in
dichloromethane at -78 °C followed by addition of
hexanes at 0 °C afforded a red powder (22-[MeB(ArF)3]).
The elemental analysis was consistent with the com-
position “[Ti(O2tBuNN′)Me]‚[MeB(ArF)3]‚0.15(CH2Cl2)”.
1
The ambient-temperature H, 13C{1H}, and 19F NMR
spectra of the compound in dichloromethane-d2 showed
a noncoordinated [MeB(ArF)3]- anion,38 a Ti-Me ligand,
and resonances consistent with a Cs symmetric cation
t
(i.e., equivalent OC6H2 Bu2 rings; one pair of mutually
coupled doublets for the NCH2Ar H atoms and a singlet
for the CH2pyridyl H atoms). Surprisingly, the putative
five-coordinate monomethyl cation is stable for several
hours in dichloromethane-d2 at ambient temperature.
Furthermore, when ethylene was admitted to the evacu-
ated headspace of an NMR tube sample, no evidence
for enchainment was noted before the sample degraded
in essentially the same manner as when no ethylene
was present. A further NMR tube experiment between
14 and [CPh3][B(ArF)4] in dichloromethane-d2 led to an
identical titanium-containing cation (along with the
expected side-product MeCPh3), confirming that the
[MeB(ArF)3]- anion has no significant effect.
Our interpretation of the NMR data is not necessarily
inconsistent with Kol’s report that [Zr(OtBu2NN*)(CH2-
Ph)]+ and related zirconium monobenzyl cations exist
as five-coordinate monomeric cations since there is a
likelihood that these could be stabilized by additional
phenyl ring ipso carbon (partial η2) coordination. On the
other hand, the lowest temperature at which Kol’s data
could be recorded in chlorobenzene-d5 was -35 °C, and
tBu
in principle a dimeric species of the type [Zr2(O2
-
NN*)2(CH2Ph)2]2+ could still be in fast exchange on the
NMR time scale at this temperature.
However, regardless of the nature of the first-formed
initiating benzyl cation, after the first enchainment of
monomer it may be possible that the subsequent propa-
gating species are dimeric in nature.39 Further work will
be needed to address this question and the possible
Cooling an NMR sample of “[Ti(O2tBuNN′)Me]‚[MeB-
(ArF)3]” (22-[MeB(ArF)3]) in dichloromethane-d2 (1H
frequency 500 MHz) led first to broadening and then
subsequently (below 213 K) to decoalescence of most of
implications with regards to8,9,11,14 (i) why titanium-
tBu
based systems based on the ligands O2tBuNN′ and O2
-
t
the methylene and OC6H2 Bu2 moiety H atom reso-
NN* and their homologues are less effective polymeri-
zation catalysts than their zirconium congeners; (ii) why
nances. The H atom resonances for the pyridyl and Ti-
Me groups were virtually unchanged on cooling, as was
the methyl group resonance of the [MeB(ArF)3]- anion.
At 183 K the 1H and 13C{1H} spectra conclusively show
C1 symmetry; the 19F NMR spectrum at this tem-
(38) Horton, A. D. Organometallics 1996, 15, 2675.
(39) Said, M.; Hughes, D. L.; Bochmann, M. Dalton Trans. 2004,
359.

322 Organometallics, Vol. 24, No. 2, 2005
Boyd et al.
[HNMe2Ph][BArF4] were provided by DSM Research, and MAO
was provided by Albermarle. 1-Hexene, pyridine, tBuNH2, and
anilines were dried over the appropriate drying agents and
distilled under reduced pressure. All other compounds and
reagents were purchased and used without further purifica-
tion.
polymerization activities are higher for less effective
Lewis base donors; (iii) the long lifetime and living
nature of such catalyst systems if their resting states
are in fact moderately stable six-coordinate dimers.
Conclusions
Na2O2tBuN (1). To a stirred suspension of NaH (0.48 g, 20.2
mmol) in THF (20 mL) was added a stirred solution of
H2O2tBuN (2.50 g. 5.04 mmol) in THF (20 mL) dropwise at -80
°C. Upon warming to room temperature, a gas (presumably
H2) was evolved. The cloudy gray solution was stirred at room
temperature for 24 h. The resulting solution was filtered,
volatiles were removed under reduced pressure, and the
resulting cream powder was dried under reduced pressure.
Yield: 2.49 g (92%). An analytically pure sample of 1‚THF was
obtained by recrystallization from a saturated THF/pentane
solution at -30 °C.
The previously reported O2RNN′ ligand provides
versatile support for a range of organometallic and
coordination complexes of scandium, yttrium, and tita-
nium. Compounds may be prepared via protonolysis or
salt elimination methods. The O2RNN′ ligands have an
overwhelming tendency to enforce six-coordination (and
also higher for the larger Y), resulting in the formation
of dimeric species where necessary to achieve this. The
steric protection provided by the phenoxide ring ortho
tert-butyl groups of O2tBuNN′ is inadequate for blocking
dimerization through the phenoxy O atoms for larger
or more Lewis acidic metal centers. CO2 cycloaddition
products of imidotitanium complexes are not stable,
although the products of imido group transfer are clearly
observed. Monoalkyl cations derived from M(O2RNN′)-
R2 appear to be dimeric for M ) Ti and R ) Me, and
the propagating species in living polymerization cata-
lysts derived from M(O2RNN′)R2, and their analogues
in general, might also be dimeric, at least in the resting
state. This stabilizing effect might clearly have implica-
tions with regard to the long lifetime and living nature
of such catalyst systems.
4
1H NMR (pyridine-d5, 300.0 MHz, 293 K): 7.51 (2H, d, J
t
4
t
) 2.5 Hz, 4-C6H2 Bu2), 7.27 (2H, d, J ) 2.5 Hz, 6-C6H2 Bu2),
t
4.6-3.8 (4H, br s, CH2C6H2 Bu2), 2.67 (2H, m, CH2CH2CH3),
t
1.67 (20H, overlapping s and m, 3-C6H2 Bu2 and CH2CH2CH3),
t
1.46 (18H, s, 5-C6H2 Bu2), 0.66 (3H, t, 3J ) 7.0 Hz, CH2-
CH2CH3). 13C{1H} NMR (pyridine-d5, 75.5 MHz, 293 K): 168.3
t
t
t
(2-C6H2 Bu2), 137.4 (1-C6H2 Bu2), 130.5 (3-C6H2 Bu2), 127.8 (5-
C6H2 Bu2), 127.1 (6-C6H2 Bu2), 123.1 (4-C6H2 Bu2), 60.8 (CH2-
C6H2 Bu2), 53.0 (CH2CH2CH3), 36.2 (C6H2(CMe3)2), 34.4 (C6H2-
t
t
t
t
(CMe3)2), 33.0 (C6H2(CMe3)2), 30.5 (C6H2(CMe3)2), 16.3 (CH2CH2-
CH3), 12.7 (CH2CH2CH3). IR data (KBr pellet, cm-1): 2956 (s),
2870 (s), 1602 (w), 1434 (s), 1414 (s), 1382 (w), 1360 (s), 1314
(s), 1258 (m), 1234 (m), 1200 (m), 1160 (w), 1050 (m), 1024
(w), 882 (m), 828 (w), 804(w), 734 (w), 642 (w), 512 (w). Anal.
Found (calcd for C33H51NNa2O2‚C4H8O): C 72.3 (72.6), H 9.6
(9.7), N 2.5 (2.3).
Sc(O2tBuNN′)Cl(py) (2). To a stirred slurry of ScCl3 (0.820
g, 1.39 mmol) in THF (30 mL), cooled to -78 °C, was added
dropwise a solution of Na2O2tBuNN′ (0.211 g, 1.39 mmol) in
THF (30 mL). Shortly afterward an excess of pyridine (10 mL)
was added. The solution was stirred at -78 °C for 1 h and
was then allowed to warm to room temperature. After 16 h
the volatiles were removed under reduced pressure. The
product was extracted into benzene (40 mL), filtered, and
concentrated to 5 mL to give a white powder, from which the
mother liquor was decanted. Subsequent washing with pen-
tane (2 × 25 mL) and drying in vacuo gave 2 as a white
powder. Yield: 0.577 g (59%). Diffraction-quality crystals were
grown by slow evaporation of a benzene solution.
Experimental Section
General Methods and Instrumentation. All manipula-
tions were carried out using standard Schlenk line or drybox
techniques under an atmosphere of argon or of dinitrogen.
Protio- and deutero-solvents were predried over activated 4 Å
molecular sieves and were refluxed over the appropriate drying
agent, distilled, and stored under dinitrogen in Teflon valve
ampules. NMR samples were prepared under dinitrogen in 5
mm Wilmad 507-PP tubes fitted with J. Young Teflon valves.
1H, 13C{1H}, 13C, and 19F NMR spectra were recorded on Varian
Mercury-VX 300 and Varian Unity Plus 500 spectrometers.
1H and 13C assignments were confirmed when necessary with
1
the use of DEPT-135, DEPT-90, and two-dimensional H-1H
1H NMR (toluene-d8, 500.0 MHz, 279 K): 9.29 (1H, d, 3J
and 13C-1H NMR experiments. 1H and 13C spectra were
referenced internally to residual protio-solvent (1H) or solvent
(13C) resonances and are reported relative to tetramethylsilane
(δ ) 0 ppm). 19F spectra were referenced externally to CFCl3
19F. Chemical shifts are quoted in δ (ppm) and coupling
constants in hertz. Infrared spectra were prepared as KBr
pellets or as Nujol mulls between NaCl plates and were
recorded on Perkin-Elmer 1600 and 1710 series FTIR spec-
trometers. Infrared data are quoted in wavenumbers (cm-1).
Mass spectra were recorded by the mass spectrometry service
of the University of Oxford Inorganic Chemistry Laboratory
or Dyson Perrins Laboratory, and elemental analyses by the
analytical services of the University of Oxford Inorganic
Chemistry Laboratory. GPC polymer analysis was performed
by Rapra Technology Ltd.
3
5.0 Hz, 6-C5H4N), 9.26 (2H, d, J 5.0 Hz, 2-C5H5N), 7.42 (2H,
d, 4J 2.0 Hz, 4-C6H2 Bu2), 6.97 (2H, d, 4J 2.0 Hz, 6-C6H2 Bu2),
t
t
3
6.75 (1H, t, J 7.5 Hz, 4-C5H5N), 6.48-6.33 (3H, overlapping
3
2 × m, 3-C5H5N and 4-C5H4N), 6.14 (1H, app. t, app. J 6.5
3
Hz, 5-C5H4N), 5.68 (1H, d, J 8.0 Hz, 3-C5H4N), 3.92 (2H, d,
2J 12.5 Hz, NCH2Ar distal to C5H4N), 3.29 (2H, s, NCH2C5H4N),
2.79 (2H, d, 2J 12.5 Hz, NCH2Ar proximal to C5H4N), 1.80
t
t
(18H, s, 3-C6H2 Bu2), 1.41 (18H, s, 5-C6H2 Bu2). 13C{1H} NMR
t
(toluene-d8, 125.7 MHz, 279 K): 161.2 (2-C6H2 Bu2)), 157.9 (2-
C5H4N), 150.9 (6-C5H4N), 150.6 (2-C5H5N), 139.0 (3-C5H5N),
t
138.0 (4-C5H4N), 136.5 (3-C6H2 Bu2), 125.4 (4-C5H5N), 124.7
t
t
t
(6-C6H2 Bu2), 124.1 (4-C6H2 Bu2), 123.4 (1-C6H2 Bu2), 121.4 (5-
C5H4N), 120.6 (3-C5H4N), 64.2 (NCH2Ar), 57.1 (NCH2C5H4N),
35.4 (3-C6H2(CMe3)2), 34.2 (5-C6H2(CMe3)2), 32.2 (5-C6H2-
t
(CMe3)2), 30.3 (3-C6H2(CMe3)2), 5-C6H2 Bu2 not observed, pos-
Literature Preparations and Other Starting Materi-
als. The compounds H2O2tBuNN′,20 H2O2MeNN′,7 Na2O2tBuNN′,7
Na2O2MeNN′,7 H2O2tBuN,10 [Ti(NR)Cl2(py)3] (R ) tBu, 2,6-C6H3-
sibly obscured or overlapping with solvent or other compound
resonances. IR (NaCl plates, Nujol mull, cm-1): 1869 (w), 1845
(w), 1829 (w), 1811(vw), 1793 (vw), 1772 (w), 1761 (vw), 1749
(w), 1734 (w), 1717 (w), 1698 (w), 1684 (w), 1670 (w), 1663
(vw), 1654 (w), 1647 (w), 1636 (vw), 1605 (vs), 1569 (w), 1559
(w), 1541 (m), 1522 (w), 1508 (m), 1446 (vs), 1417 (s), 1362 (s),
1340 (w), 1322 (m), 1307 (s), 1281 (s), 1240 (m), 1215 (m), 1204
(m), 1170 (m), 1155 (w), 1132 (m), 1099 (w), 1070 (w), 1054
(m), 1039 (w), 1019 (w), 1012 (m), 974 (m), 949 (vw), 932 (m),
Me2, 2,6-C6H3 Pr2),36 Sc(CH2SiMe3)3(THF)2,40 Y(CH2SiMe3)3-
i
(THF)2,40 and TiCl4(THF)2 were prepared according to pub-
41
lished methods. The compounds BArF3, [Ph3C][BArF4], and
(40) Lappert, M. F.; Pearce, R. J. Chem. Soc., Chem. Commun. 1973,
126.
(41) Manzer, L. E. Inorg. Synth. 1982, 21, 135.

Diamino-bis(phenolate) Ti, Sc, and Y Complexes
Organometallics, Vol. 24, No. 2, 2005 323
t
t
t
915 (m), 880 (m), 839 (s), 777 (w), 753 (s), 702 (m), 683 (vs),
633 (s). EIMS: m/z 623 (100%), [M - C5H5N]+. Anal. Found
(calcd for C41H55ClN2O2Sc‚1.2(C6H6)): C, 72.9 (72.7); H, 7.9
(7.7); N, 5.0 (5.3).
C6H2 Bu2), 135.4 (3-C6H2 Bu2), 125.2 (4-C6H2 Bu2), 124.8 (3-
t
t
C5H5N), 123.8 (6-C6H2 Bu2), 123.0 (1-C6H2 Bu2), 122.0 (5-
C5H4N), 121.7 (3-C5H4N), 64.1 (NCH2C5H4N), 53-51 (very
broad NCH2Ar), 35.3 (3-C6H2(CMe3)2), 34.2 (5-C6H2(CMe3)2),
32.1 (5-C6H2(CMe3)2), 30.2 (3-C6H2(CMe3)2). IR (KBr plates,
Nujol mull, cm-1): 2280 (vw), 1861 (vw), 1765 (vw), 1726 (vw),
1711 (vw), 1693 (vw), 1659 (vw), 1603 (vs), 1571 (m), 1513 (w),
1446 (s), 1415 (s), 1361 (s), 1329 (s), 1303 (vs), 1289 (s), 1277
(s), 1240 (s), 1221 (w), 1204 (m), 1169 (m), 1153 (m), 1135 (m),
1096 (m), 1070 (s), 1056 (m), 1038 (s), 1026 (m), 1011 (s), 980
(w), 984 (w), 943 (w), 915 (w), 877 (s), 863 (m), 837 (s), 781
(w), 762 (m), 751 (s), 700 (s), 646 (m), 626 (m). Found (calcd
for C82H110Cl2N6O4Y2): C, 66.4 (66.0); H, 7.5 (7.6); N, 5.8 (5.6).
Sc(O2tBuNN′)(CH2SiMe3)(THF) (5). To a solution of Sc-
Sc2(O2MeNN′)2Cl2 (3). To a stirred slurry of ScCl3 (0.205 g,
1.36 mmol) in THF (25 mL), cooled to -78 °C, was added
dropwise a solution of Na2O2MeNN′‚0.3THF (0.600 g, 1.36
mmol) in THF (20 mL). The mixture was allowed to warm to
room temperature and was stirred for 16 h. The volatiles were
removed under reduced pressure and the residues extracted
into dichloromethane (50 mL), filtered, and concentrated to
25 mL, after which hexanes (20 mL) were added. Cooling to
-80 °C for 16 h produced a white precipitate, from which the
mother liquor was decanted. The white powder was dried in
vacuo to give 3. Yield: 0.285 g (45%). Diffraction-quality
crystals were grown by slow evaporation of a dichloromethane
solution.
(CH2SiMe3)3(THF)2 (0.250 g, 0.597 mmol) in THF (25 mL),
cooled to -78 °C, was added dropwise a solution of H2O2
tBu
-
NN′ (0.325 g. 0.597 mmol) in THF (15 mL). The solution was
then allowed to warm to room temperature and was stirred
for a further 2 h, after which the volatiles were removed under
reduced pressure to give a pale yellow powder. This was
extracted into pentane (3 × 20 mL) and filtered, and the
solution was concentrated to 30 mL. Cooling to -80 °C for 16
h gave a white powder, from which the mother liquor was
decanted. The white powder was dried in vacuo to give 5.
Yield: 0.255 g (63%).
3
1H NMR (benzene-d6, 300.1 MHz, 293 K): 9.14 (2H, d, J
4.5 Hz, 6-C5H4N), 7.40 (2H, app. td, app. 3J 7.5 Hz, 4J 1.5 Hz,
4-C5H4N), 6.88 (2H, app. t, app. 3J 6.5 Hz 5-C5H4N), 6.79 (2H,
3
s, 4-C6H2Me2 (a)), 6.76 (2H, s, 6-C6H2Me2 (a)), 6.70 (2H, d, J
7.0 Hz, 3-C5H4N), 6.61 (2H, s, 6-C6H2Me2 (b)), 6.40-6.35 (3H,
overlapping m, 4-C6H2Me2 (b) and NCH2), 5.00 (2H, d, 2J 14.0
Hz, NCH2), 4.34 (2H, d, 2J 15.5 Hz, NCH2), 3.37 (2H, d, 2J
14.0 Hz, NCH2), 3.25-3.17 (4H, overlapping m, 2 × NCH2),
2.20 (6H, s, 3-C6H2Me2 (a)), 2.01 (6H, s, 3-C6H2Me2 (b)), 1.86
(6H, s, 5-C6H2Me2 (b)), 1.81 (6H, s, 5-C6H2Me2 (a)). 13C{1H}
NMR (benzene-d6, 125.7 MHz, 293 K): 159.7 (2-C5H4N), 159.0
(2-C6H2Me2 (a)) 155.7 (2-C6H2Me2 (b)), 150.6 (6-C5H4N), 139.1
(4-C5H4N), 132.4 (4-C6H2Me2 (b)), 131.5 (4-C6H2Me2 (a)), 129.8
(5-C6H2Me2 (b)), 129.5 (6-C6H2Me2 (b)), 128.2 (6-C6H2Me2 (a)),
127.8 (3-C6H2Me2 (b)), 126.1 (5-C6H2Me2 (a)), 125.9 (3-C6H2-
Me2 (a)), 125.5 (1-C6H2Me2 (b)), 122.6 (1-C6H2Me2 (a)), 122.4
(5-C5H4N), 121.9 (3-C5H4N), 65.5 (NCH2), 63.5 (NCH2), 60.3
(NCH2), 20.5 (5-C6H2Me2 (a)), 20.1 (5-C6H2Me2 (b)), 16.4 (3-
C6H2Me2 (b)), 16.0 (3-C6H2Me2 (a)), the designations (a) and
(b) relate groups of resonances for the same phenoxy groups.
IR (KBr plates, Nujol mull, cm-1): 1608 (m), 1572 (w), 1484
(vs), 1397 (w), 1350 (w), 1311 (s), 1278 (s), 1261 (m), 1215 (s),
1205 (m), 1153 (s), 1099 (m), 1057 (w), 1017 (m), 974 (m), 963
(w), 945 (w), 902 (w), 852 (s), 838 (m), 791 (s), 756 (m), 643
(w), 625 (m), 579 (m), 554 (m). EI-HRMS: m/z found (calcd
for C48H52Cl2N4O4Sc2, [M]+) 908.2496 (908.2484). Anal. Found
(calcd for C48H52Cl2N4O4Sc2): C, 63.5 (63.4); H, 6.1 (5.8); N,
6.3 (6.2).
1H NMR (benzene-d6, 300.1 MHz, 293 K): 8.72 (1H, d, J
3
4.5 Hz, 6-C5H4N), 7.36 (2H, d, 4J 2.5 Hz, 4-C6H2 Bu2, 6.95 (2H,
t
4
t
3
4
d, J 2.5 Hz, 6-C6H2 Bu2, 6.39 (1H, app.td, app. J 8.0 Hz, J
1.5 Hz, 4-C5H4N, 6.12 (1H, at, a 3J 6.0 Hz, 5-C5H4N, 5.72 (1H,
d, 3J 8.0 Hz, 3-C5H4N, 4.04 (4H, br s, 2-C4H8O, 3.09 (2H, d, 2J
12.5 Hz, NCH2Ar distal to C5H4N, 3.13 (2H, s, NCH2C5H4N,
2.85 (2H, d, 2J 12.5 Hz, NCH2Ar proximal to C5H4N, 1.68 (18H,
t
t
s, 3-C6H2 Bu2, 1.36 (18H, s, 5-C6H2 Bu2, 1.22 (4H, br m,
3-C4H8O, 0.55 (9H, s, CH2SiMe3, 0.40 (2H, s, CH2SiMe3. 13C-
{1H} NMR (benzene-d6, 75.5 MHz, 293 K): 161.6 (2-C6H2 Bu),
t
159.0 (2-C5H4N), 149.6 (6-C5H4N), 137.5 (4-C5H4N), 136.8 (5-
t
t
t
C6H2 Bu2), 136.3 (3-C6H2 Bu2), 124.9 (4-C6H2 Bu2), 124.1 (6-
t
t
C6H2 Bu2), 123.6 (1-C6H2 Bu2), 121.2 (5-C5H4N), 121.1 (3-
C5H4N), 69.6 (2-C4H8O), 64.4 (NCH2Ar), 57.1 (NCH2C5H4N),
35.5 (3-C6H2(CMe3)2), 34.1 (5-C6H2(CMe3)2), 32.2 (5-C6H2-
(CMe3)2), 30.4 (3-C6H2(CMe3)2), 4.0 (CH2SiMe3), 0.0 (CH2SiMe3),
3-C4H8O not observed, possibly obscured or overlapping other
compound resonances. IR (KBr plates, Nujol mull, cm-1): 2350
(w), 2284 (w), 1606 (s), 1570 (m), 1416 (s), 1321 (m), 1307 (s),
1237 (s), 1203 (m), 1168 (m), 1156 (w), 1132 (m), 1103 (m),
1069 (m), 1057 (m), 1019 (s), 974 (m), 934 (w), 915 (m), 868
(vs), 844 (s), 779 (w), 746 (s), 723 (s), 668 (m), 645 (m), 631
(w), 546 (m). EIMS: m/z 587 (65%), [M - CH2SiMe3, - THF]+.
Anal. Found (calcd for C44H69N2O3ScSi): C, 71.0 (70.7); H, 9.0
(9.3); N, 4.2 (3.8).
Y2(O2tBuNN′)2(µ-Cl)2(py)2 (4). To a stirred solution of YCl3
(0.232 g, 1.19 mmol) in pyridine (35 mL), cooled to -30 °C,
was added dropwise a solution of Na2O2tBuNN′ (0.700 g, 1.19
mmol) in pyridine (25 mL). The solution was allowed to warm
to room temperature and was stirred for 16 h, after which the
volatiles were removed under reduced pressure to give a cream
powder. This was extracted into benzene (40 mL) and filtered,
and the solution was concentrated to 20 mL, after which
pentane (20 mL) was added. Cooling the solution to -30 °C
for 16 h produced a bright white precipitate, from which the
mother liquor was filtered. The powder was washed with
pentane (2 × 25 mL) and dried under reduced pressure to give
4. Yield: 0.657 g (74%). Diffraction-quality crystals were grown
from a saturated benzene solution at room temperature.
1H NMR (dichloromethane-d2, 300.1 MHz, 293 K): 9.06 (4H,
dd, 3J 6.0 Hz, 4J 1.5, Hz 2-C5H5N), 8.84 (2H, d, 3J 4.5 Hz,
Y(O2tBuNN′)(CH2SiMe3)(THF) (6). To a stirred solution of
Y(CH2SiMe3)3(THF)2 (0.500 g, 1.01 mmol) in benzene (20 mL),
cooled to 7 °C, was added dropwise a solution of H2O2tBuNN′
(0.550 g, 1.01 mmol) in benzene (15 mL). The solution was
allowed to warm to room temperature and then stirred for 16
h. The volatiles were removed under reduced pressure to give
6 as a cream powder, which was dried in vacuo. Yield: 0.613
g (77%). Attempts to recrystallize this compound led to sample
degradation.
1H NMR (dichloromethane-d2, 500.0 MHz, 293 K): 8.57 (1H,
d, J 5.0 Hz, 6-C5H5N), 7.29 (1H, app. td, app. J 8.0 Hz, J
2.0 Hz, 4-C5H4N), 7.02 (2H, d, J 2.5 Hz, 4-C6H2 Bu2), 6.93-
6.88 (3H, overlapping m, 6-C6H2 Bu and 5-C5H4N), 6.57 (1H,
3
3
4
3
4
t
6-C5H4N), 7.93 (2H, t, J 7.5 Hz, 4-C5H5N), 7.50 (4H, app. td,
4
3
t
app.3J 6.0 Hz, J 1.0 Hz, 3-C5H5N), 7.36 (2H, app. td, app. J
4
4
t
3
8.0 Hz, J 1.5 Hz, 4-C5H4N), 7.05 (4H, d, J 2.5, 4-C6H2 Bu2),
d, J 8.0 Hz, 3-C5H4N), 4.36 (4H, br s, 2-C4H8O), 4.10 (2H, d,
6.97 (2H, app. t, app. 3J 5.5 Hz, 5-C5H5N), 6.90 (4H, d, 4J 2.5,
2J 12.0 Hz, NCH2Ar distal to C5H4N), 3.63 (2H, s, NCH2C5H4N),
3.23 (2H, d, 2J 12.0 Hz, NCH2Ar proximal to C5H4N), 2.02 (2H,
t
3
2
6-C6H2 Bu2), 6.64 (2H, d, J 8.0 Hz, 3-C5H4N), 4.16 (4H, d, J
11.5 Hz, NCH2Ar), 3.76 (4H, s, NCH2C5H4N), 3.30 (4H, d, J
2
t
br m, 3-C4H8O), 1.37 (18H, s, 3-C6H2 Bu2), 1.23 (18H, s,
t
t
2
12.5 Hz, NCH2Ar), 1.39 (36H, s, 3-C6H2 Bu2), 1.24 (36H, s,
5-C6H2 Bu2), 0.06 (9H, s, CH2SiMe3), -0.56 (2H, d, JY-H 3.0
5-C6H2 Bu2). 13C{1H} NMR (dichloromethane-d2, 125.7 MHz,
Hz, CH2SiMe3). 13C{1H} NMR (dichloromethane-d2, 75.5 MHz,
t
t
t
293 K): 160.5 (2-C6H2 Bu2), 158.9 (2-C5H4N), 149.8 (2-C5H5N),
293 K): 166.3 (2-C6H2 Bu2), 164.8 (2-C5H4N), 154.1 (6-C5H4N),
142.8 (4-C5H4N), 140.9 (5-C6H2 Bu2), 140.4 (3-C6H2 Bu2), 133.1
t
t
149.7 (6-C5H4N), 139.0 (4-C5H5N), 138.3 (4-C5H4N), 136.6 (5-

324 Organometallics, Vol. 24, No. 2, 2005
Boyd et al.
t
t
t
(6-C6H2 Bu2),), 130.3 (4-C6H2 Bu2), 128.2 (1-C6H2 Bu2), 126.9
(3-C5H4N), 126.3 (5-C5H4N), 71.9 (2-C4H8O), 64.2 (NCH2Ar),
57.3 (NCH2C5H4N), 39.7 (3-C6H2(CMe3)2), 38.5 (5-C6H2(CMe3)2),
36.5 (5-C6H2(CMe3)2), 34.5 (3-C6H2(CMe3)2), 30.2 (3-C4H8O), 8.8
(CH2SiMe3), 5.6 (CH2SiMe3). IR (KBr plates, Nujol mull, cm-1):
2361 (w), 2342 (w), 2005 (vw), 1952 (vw), 1773 (vw), 1732
(vw), 1605 (s), 1568 (m), 1415 (s), 1361 (s), 1318 (vs), 1306 (s),
1236 (s), 1202 (m), 1167 (m), 1155 (w), 1131 (m), 1101 (s), 1105
(s), 1018 (vs), 967 (m), 948 (vw), 932 (w), 912 (m), 902 (m),
872 (s), 835 (vs), 806 (vs), 780 (m), 762 (s), 743 (s), 721 (m),
676 (s), 644 (m), 629 (w), 601 (m). Anal. Found (calcd for
C44H69N2O3SiY): C, 65.3 (67.0); H, 8.5 (8.6); N 3.5 (3.6).
liquor decanted. The product was washed with pentane at -78
°C (2 × 10 mL) and dried in vacuo to give 8. Yield: 0.110 g
(41%).
1H NMR (dichloromethane-d2 300.1 MHz, 293 K): 8.46 (1H,
3
3
4
d, J 4.5 Hz, 6-C5H4N), 7.52 (1H, app. td, app. J 7.5 Hz, J
1.5 Hz, 4-C5H4N), 7.39-7.33 (3H, overlapping m, o- or m-, and
p-C6H5), 7.28-7.24 (2H, m, o- or m-C6H5), 7.12 (1H, app. t,
app. 3J 6.5 Hz, 5-C5H4N), 6.83 (1H, d, 3J 8.0 Hz, 3-C5H4N),
6.66 (4H, overlapping s, 4- and 6-C6H2Me2), 4.01 (2H, s,
NCH2C5H4N), 3.69 (2H, d, 2J 12 Hz, NCH2Ar distal to C5H4N),
3.58 (2H, d, 2J 12 Hz, NCH2Ar proximal to C5H4N), 2.13 (6H,
s, 3-C6H2Me2), 2.03 (6H, s, 5-C6H2Me2), -0.24 18H, s, SiNMe3).
13C{1H} NMR (dichloromethane-d2, 75.5 MHz, 293 K): 182.1
(C6H5C(NSiMe3)2), 160.3 (2-C6H2Me2), 157.4 (2-C5H4N), 145.8
(6-C5H4N), 142.7 (i-C6H5), 138.7 (4-C5H4N), 131.4 (5- or 3-C6H2-
Me2), 128.1 (5- or 3-C6H2Me2), 128.0 (o- or m-, or p-C6H5), 127.9
(o- or m-, or p-C6H5), 126.8 (o- or m-C6H5), 125.3 (6-C6H2Me2),
124.1 (1-C6H2Me2), 123.1 (4-C6H2Me2), 122.7 (5-C5H4N), 121.7
(3-C5H4N), 62.9 (NCH2C5H4N), 62.0 (NCH2Ar), 20.4 (3-C6H2-
Me2), 16.9 (5-C6H2Me2), 2.1 (NSiMe3). IR (KBr plates, Nujol
mull, cm-1): 2727 (vw), 2361 (m), 1869 (vw), 1845 (vw), 1829
(vw), 1793 (vw), 1772 (w), 1749 (w), 1734 (vw), 1717 (vw), 1699
(vw), 1684 (vw), 1670 (vw), 1654 (w), 1636 (vw), 1608 (m), 1570
(vw), 1559 (vw), 1542 (w), 1522 (vw), 1508 (m), 1341 (w), 1323
(m), 1312 (m), 1291 (w), 1260 (m), 1245 (m), 1162 (bm), 1021
(m), 1006 (m), 995 (m), 964 (w), 946 (vw), 838 (vs), 757 (s),
700 (w), 593 (vw). EIMS: m/z 665 (37%), [M, - CH3, - 2H]+;
m/z 574 (9%), [M, - C6H5, - 2CH3]+. Anal. Found (calcd for
C37H4
Sc(O2tBuNN′){PhC(NSiMe3)2} (7). To a slurry of ScCl3
(0.1285 g, 0.8492 mmol) in THF (25 mL), cooled to -78 °C,
was added dropwise a solution of Na2O2tBuNN (3) (0.500 g,
0.849 mmol) in THF (20 mL). The solution was stirred at -78
°C for 20 min, after which time it was allowed to warm to room
temperature and was stirred for a further 90 min. The solution
was then again cooled to -78 °C for the dropwise addition of
a solution of Li[PhC(NSiMe3)2] (0.229 g, 0.849 mmol) in THF
(15 mL). The solution was stirred at -78 °C for 20 min, after
which time it was allowed to warm to room temperature and
was then stirred for a further 3 h. The volatiles were removed
under reduced pressure to yield a white powder. This was
extracted into pentane (50 mL) and filtered, and the solution
was concentrated to 10 mL. Cooling to -30 °C for 16 h
produced a white precipitate, from which the mother liquor
was decanted. The white powder was dried in vacuo to give 7.
Yield: 0.313 g (43%).
Ti(O2tBuNN′)Cl2 (9). To a stirred yellow solution of TiCl4-
(THF)2 (1.312 g, 3.93 mmol) in diethyl ether (40 mL) cooled to
-40 °C was added dropwise a solution of MeLi (1.6 M in Et2O,
1H NMR (dichloromethane-d2, 300.1 MHz, 213 K): 8.30 (1H,
d, J 5.0 Hz, 6-C5H4N), 7.44 (1H, app. td, app. J 7.5 Hz, J
1.0 Hz, 4-C5H4N), 7.32 (3H, m, o- or m-, and p-C6H5), 7.18 (2H,
3
3
4
4.91 mL, 7.93 mmol). The solution was stirred for 1 h at -40
3
tBu
m, o- or m-C6H5), 7.05 (1H, app. t, app. J 6.0 Hz, 5-C5H4N),
°C. To this solution was added dropwise a solution of H2O2
-
t
t
NN′ (2.140 g, 3.93 mmol) in diethyl ether (40 mL). The solution
was allowed to stir for 1 h at -40 °C before warming to room
temperature. After stirring for a further 1 h the volatiles were
removed under reduced pressure. The residues were extracted
with dichloromethane (100 mL), filtered, and concentrated to
30 mL, and hexanes (30 mL) were added. Cooling to -80 °C
produced a dark orange precipitate, from which the mother
liquor was decanted. This was washed with cold hexanes (2 ×
30 mL) and dried in vacuo to give 9. Yield: 3.67 g (70%).
Diffraction-quality crystals were grown by slow evaporation
of a dichloromethane solution.
6.94 (2H, br s, 4-C6H2 Bu2), 6.89 (2H, s, 6-C6H2 Bu2), 6.71 (1H,
d, 3J 8.0 Hz, 3-C5H4N), 4.00 (2H, s, NCH2C5H4N), 3.85 (2H, br
d, 2J 11.0 Hz, NCH2Ar distal to C5H4N), 3.66 (2H, vbr s, NCH2-
Ar proximal to C5H4N), 1.32 (18H, br s, 3-C6H2 Bu2), 1.19 (18H,
s, 5-C6H2 Bu2), -0.08 (9H, s, NSiMe3 (a)), -0.58 (9H, s, NSiMe3
(b)), which NSiMe3, designated (a) and (b), lies cis and which
lies trans to the pyridyl donor could not be determined. 13C-
{1H} NMR (dichloromethane-d2, 125.7 MHz, 213 K): 181.4
(C6H5C(NSiMe3)2), 160.4 (2-C6H2 Bu2), 156.6 (2-C5H4N), 146.6
(6-C5H4N), 142.1 (i-C6H5), 138.3 (4-C5H4N), 136.2 (5- or 3-C6H2 -
t
t
t
t
t
Bu2), 134.2 (5- or 3-C6H2 Bu2), 127.5 (o- or m-, and p-C6H5),
126.3 (o- or m- C6H5), 124.5 (6-C6H2 Bu2), 123.0 (1-C6H2 Bu2),
122.9 (4-C6H2 Bu2), 121.7 (5-C5H4N), 120.7 (3-C5H4N), 61.4
3
1H NMR (benzene-d6, 300.1 MHz, 293 K): 9.04 (1H, d, J
t
t
6.0 Hz, 6-C5H4N), 7.55 (1H, d, 4J 2.5 Hz, 4-C6H2 Bu2 (a)), 7.06
t
t
(1H, d, 4J 3.0 Hz, 6-C6H2 Bu2 (a)), 7.01 (1H, d, 4J 2.5 Hz,
t
(NCH2C5H4N), 33.5 (3-C6H2(CMe3)2), 33.5 (5-C6H2(CMe3)2),
31.2 (5-C6H2(CMe3)2), 29.4 (3-C6H2(CMe3)2), 2.0 (NSiMe3 (a)),
1.7 (NSiMe3 (b)), NCH2py not observed, possibly overlapping
other compound resonances. IR (KBr plates, Nujol mull, cm-1):
2359 (w), 1893 (vw), 1869 (vw), 1845 (vw), 1772 (vw), 1734
(vw), 1717 (vw), 1698 (vw), 1653 (w), 1610 (m), 1572 (m), 1559
(vw), 1541 (vw), 1417 (m), 1361 (m), 1336 (w), 1322 (s), 1304
(s), 1245 (s), 1203 (m), 1170 (m), 1155 (w), 1131 (m), 1103 (m),
1056 (w), 1034 (m), 1018 (s), 1005 (s), 995 (m), 972 (w), 952
(w), 934 (w), 924 (m), 914 (w), 898 (w), 874 (m), 867 (m), 842
(vs), 793 (m), 765 (s), 754 (s), 709 (m), 686 (w), 645 (w), 546
(m). EI-HRMS: m/z found (calcd for C49H73N4O2Si2Sc, [M]+)
850.5013 (850.4831). Anal. Found (calcd for C49H73N4O2Si2-
Sc): C, 68.9 (69.1); H, 8.5 (8.6); N, 6.5 (6.6).
Sc(O2MeNN′){PhC(NSiMe3)2} (8). To a stirred slurry of
Sc2(O2tBuNN′)2Cl2 (3) (0.185 g 1.97 mmol) in THF (25 mL),
cooled to -78 °C, was added dropwise a solution of Li[PhC-
(NSiMe3)2] (0.532 g 1.970 mmol) in THF (15 mL). The solution
was allowed to warm to room temperature and stirred for 1
h, after which time the volatiles were removed under reduced
pressure. The product was extracted into pentane (50 mL) and
filtered, and the solution was concentrated to 20 mL. Cooling
to -30 °C produced a white precipitate from which the mother
4-C6H2 Bu2 (b)), 6.46 (1H, app. td, a 3J 7.5 Hz, app. 4J 1.0 Hz,
t
4-C5H4N), 6.32 (1H, d, 4J 3.0 Hz, 6-C6H2 Bu2 (b)), 6.09 (1H, at,
t
3
3
a J 6.5 Hz, 5-C5H4N), 5.99 (1H, d, J 8.0 Hz, 3-C5H4N), 5.35
(1H, d, 2J 13.0 Hz NCH2Ar (a)), 4.51 (1H, d, 2J 15.0 Hz,
NCH2C5H4N), 3.60 (1H, d, 2J 13.0 Hz, NCH2Ar (b)), 2.92 (1H,
d, 2J 13.5 Hz NCH2Ar (a)), 2.90 (1H, d, 2J 15.0 Hz, NCH2-
C5H4N), 2.21 (1H, d, 2J 13.0 Hz, NCH2Ar (b)), 1.81 (9H, s,
t
t
3-C6H2 Bu2 (a)), 1.58 (9H, s, 3-C6H2 Bu2 (b)), 1.44 (9H, s,
t
t
5-C6H2 Bu2 (a)), 1.16 (9H, s, 5-C6H2 Bu2 (b)). Further reso-
nances at 1.35 and 1.62 as well as other low-intensity and
mostly obscured peaks indicate the presence of an isomer in
which the aryl oxide rings are positioned cis to each other (i.e.,
t
Cs symmetry). These peaks relate to (18H, s, 5-C6H2 Bu2) and
(18H, s, 3-C6H2 Bu2), respectively. The designations (a) and
t
(b) relate resonances to protons on a specific phenoxy group;
however which group lies cis and which trans to the pyridyl
group could not be determined. 13C{1H} NMR (benzene-d6,
t
t
125.7 MHz, 293 K): 160.5 (2-C6H2 Bu2 (b)), 158.6 (2-C6H2 Bu2
t
(a)), 155.8 (2-C5H4N), 149.6 (6-C5H4N), 144.4 (5-C6H2 Bu2 (a)),
141.8 (5-C6H2 Bu2 (b)), 138.1 (4-C5H4N), 137.1 (3-C6H2 Bu2 (a)),
135.1 (3-C6H2 Bu2 (b)), 126.9 (1-C6H2 Bu2 (a)), 125.5 (1-C6H2 -
Bu2 (b)), 124.1 (4-C6H2 Bu2 (a)), 124.0 (6-C6H2 Bu2 (a)), 123.5
t
t
t
t
t
t
t
t
t
(6-C6H2 Bu2 (b)), 123.3 (4-C6H2 Bu2 (b)), 122.5 (5-C5H4N), 122.5

Diamino-bis(phenolate) Ti, Sc, and Y Complexes
Organometallics, Vol. 24, No. 2, 2005 325
(3-C5H4N), 65.7 (NCH2C5H4N), 65.4 (NCH2Ar (a)), 61.0 (NCH2-
Ar (b), 36.1 (3-C6H2(CMe3)2 (a)), 35.3 (3-C6H2(CMe3)2 (b)), 35.1
(5-C6H2(CMe3)2 (a)), 34.5 (5-C6H2(CMe3)2 (b)), 32.2 (5-C6H2-
(CMe3)2 (a)), 32.1 (5-C6H2(CMe3)2 (b)), 30.8 (3-C6H2(CMe3)2 (b)),
30.7 (3-C6H2(CMe3)2 (a)). IR (NaCl plates, Nujol mull, cm-1):
2672 (m), 2360 (m), 2342 (m), 1610 (m), 1576 (w), 1559 (w),
1541 (w), 1522 (w), 1507 (w), 1295 (s), 1261 (s), 1241 (m), 1205
(m), 1171 (m), 1127 (w), 1025 (s), 975 (bm), 918 (s), 871 (s),
848 (s), 764 (m), 755 (m), 651 (w), 604 (w). EIMS: m/z 661
(35%), [M]+; m/z 625 (100%), [M - Cl]+. Anal. Found (calcd
for C36H50Cl2N2O2Ti‚0.6(C7H8)): C, 67.2 (67.4); H, 7.4 (7.7); N,
3.6 (3.9).
Alternative Synthesis of Ti(O2tBuNN′)Cl2 (9). To a stirred
brown solution of Ti(NMe2)Cl2 (0.395 g, 0.725 mmol) in benzene
(25 mL), cooled to 7 °C, was added dropwise a solution of
H2O2tBuNN′ (0.150 g, 0.725 mmol) in benzene (25 mL). The
solution was allowed to warm to room temperature and was
stirred for 1 h, after which time the volatiles were removed
under reduced pressure, giving a dark orange powder. This
was dissolved in toluene (50 mL), the volume was reduced to
10 mL, and hexanes (30 mL) were added. Cooling of the
solution to -80 °C produced a dark orange precipitate, which
was washed with cold hexanes (2 × 30 mL) and dried in vacuo
to give 9. Yield: 0.221 g (46%).
(a)), 20.8 (5-C6H2Me2 (b)), 20.5 (5-C6H2Me2 (a)), 16.2 (3-
C6H2Me2 (b)), 15.7 (3-C6H2Me2 (a)). IR (NaCl plates, Nujol mull,
cm-1): 1610 (m), 1294 (w), 1237 (s), 1220 (s), 1160 (s), 1059
(w), 1026 (w), 959 (w), 948 (w), 871 (s), 839 (s), 762 (w), 750
(w). EI-HRMS: m/z found (calcd for C24H26Cl2N2O2Ti, [M]+)
492.0856 (492.0851).
Ti(O2tBuNN′)(NMe2)2 (11). To a stirred yellow solution of
Ti(NMe2)4 (0.513 g, 2.29 mmol) in benzene (40 mL), cooled to
7 °C, was added dropwise a solution of H2O2tBuNN′ (1.247 g,
2.29 mmol) in benzene (50 mL). The solution was allowed to
warm to room temperature and was stirred for 1 h, after which
time the volatiles were removed under reduced pressure to
give 11 as a rusty-orange powder. Yield: 1.37 g, (88%).
Diffraction-quality crystals were grown from a saturated
benzene solution at room temperature.
3
1H NMR (benzene-d6, 300.1 MHz, 293 K): 8.21 (1H, d, J
5.0 Hz, 6-C5H4N), 7.33 (2H, d, 4J 2.5 Hz, 4-C6H2 Bu2), 6.89 (2H,
t
t
d, 4J 2.5 Hz, 6-C6H2 Bu2), 6.35 (1H, app. td, app. 3J 7.5 Hz,
app. 4J 1.5 Hz, 4-C5H4N), 6.15 (1H, app. t, app. 3J 6.5 Hz,
5-C5H4N), 5.74 (1H, d, 3J 7.5 Hz, 3-C5H4N), 4.20 (2H, d, 2J
13.0 Hz, NCH2Ar distal to C5H4N), 3.84 (6H, s, NMe2 cis to
C5H4N), 3.53 (6H, s, NMe2 trans to C5H4N), 3.14 (2H, s,
NCH2C5H4N), 2.86 (2H, d, 2J 13.0 Hz, NCH2Ar proximal to
t
t
C5H4N), 1.63 (18H, s, 3-C6H2 Bu2), 1.34 (18H, s, 5-C6H2 Bu2).
13C{1H} NMR (benzene-d6, 75.5 MHz, 293 K): 160.9 (2-C6H2 -
Bu2), 157.9 (2-C5H4N), 149.5 (6-C5H4N), 138.7 (5-C6H2 Bu2),
136.6 (4-C5H4N), 135.8 (3-C6H2 Bu2), 124.6 (1-C6H2 Bu2 or
t
Alternative NMR Tube Scale Synthesis of Ti(O2tBuNN′)-
Cl2 (9). To a solution of Ti(O2tBuNN′)(NMe2)2 (11) (0.030 g,
0.0044 mmol) in benzene-d6 (0.75 mL) in a 5 mm J. Young
NMR tube was added Me3SiCl (0.0096 g, 0.0088 mmol). After
3 days an 1H NMR spectrum confirmed that the reaction had
proceeded quantitatively to give 9 and 2 equiv of Me3SiNMe2.
t
t
t
t
t
t
t
6-C6H2 Bu2), 124.5 (1-C6H2 Bu2 or 6-C6H2 Bu2), 123.4 (4-C6H2 -
Bu2), 121.3 (5-C5H4N), 120.6 (3-C5H4N), 64.8 (NCH2Ar), 58.6
(NCH2C5H4N), 50.1 (NMe2 trans to C5H4N), 49.3 (NMe2 cis to
C5H4N), 35.6 (3-C6H2(CMe3)2), 34.4 (5-C6H2(CMe3)2), 32.3 (5-
C6H2(CMe3)2), 30.6 (3-C6H2(CMe3)2). IR (KBr plates, Nujol mull,
cm-1): 2803 (s), 2757 (s), 2360 (m), 2342 (m), 1605 (m), 1559
(w), 1542 (w), 1522 (w), 1508 (w), 1413 (s), 1377 (s), 1362 (m),
1340 (w), 1318 (m), 1302 (m), 1238 (s), 1207 (m), 1170 (m),
1151 (w), 1138 (m), 1075 (w), 1054 (m), 1017 (m), 978 (m), 961
(s), 947 (s), 916 (m), 903 (w), 878 (m), 870 (w), 838 (s), 771 (w),
759 (s). EIMS: m/z 678 (7%), [M]+. Anal. Found (calcd for
C40H62N4O2Ti): C, 70.8 (70.8); H, 9.2 (9.2); N, 8.2 (8.3).
Ti(O2MeNN′)(NMe2)2 (12). To a stirred yellow solution of
Ti(NMe2)4 (1.001 g, 4.46 mmol) in benzene (25 mL), cooled to
7 °C, was added dropwise a solution of H2O2MeNN′ (1.681 g,
4.46 mmol) in benzene (20 mL). The solution was allowed to
warm to room temperature and was stirred for 90 min, after
which time the volatiles were removed under reduced pres-
sure to give 12 as a rusty-orange powder. The product was
washed with pentane (20 mL) and dried in vacuo. Yield: 1.54
g (79%).
Ti(O2MeNN′)Cl2 (10). To a stirred solution of TiCl4(THF)2
(1.774 g, 5.31 mmol) in diethyl ether (40 mL), cooled to -40
°C, was added dropwise a solution of MeLi (1.6 M in Et2O,
6.64 mL, 10.6 mmol). The solution was stirred for 1 h at -40
°C. To this was added dropwise a solution of H2O2MeNN′ (2.00
g, 5.31 mmol) in diethyl ether (40 mL). The solution was stirred
for 1 h at -40 °C, allowed to warm to room temperature, and
then stirred for a further 1 h, after which time the volatiles
were removed under reduced pressure. The residues were
extracted into dichloromethane (100 mL) and filtered, and
hexanes (50 mL) were added to the orange solution. Cooling
to -30 °C for 16 h produced a dark orange precipitate, from
which the mother liquor was decanted. The product was dried
in vacuo at 80 °C for 16 h to give Ti(O2NN′)Cl2‚nC6H14 (10‚
nC6H14) (typical value of n ) 0.2). Yield: 1.786 g (66%). The
hexanes content n was determined by careful integration of
the 1H NMR spectrum. Diffraction-quality crystals were grown
by slow evaporation of a benzene solution.
1H NMR (benzene-d6, 300.1 MHz, 293 K): 8.40 (1H, app.
dt, 3J 4.5 Hz, app. 4J 1.0 Hz, 6-C5H4N), 6.74 (2H, d, 4J 2.0 Hz,
4-C6H2Me2), 6.59 (2H, d, 4J 2.0 Hz, 6-C6H2Me2), 6.78 (1H, app.
td, app. 3J 7.5 Hz, 4J 2.0 Hz, 4-C5H4N), 6.15 (1H, app. td, app.
3J 6.5 Hz, 4J 1.0 Hz 5-C5H4N), 5.64 (1H, d, 3J 8.0 Hz, 3-C5H4N),
4.30 (2H, d, 2J 12.5 Hz, NCH2Ar distal to C5H4N), 3.96 (6H, s,
NMe2 cis to C5H4N), 3.59 (6H, s, NMe2 trans to C5H4N), 3.18
(2H, s, NCH2C5H4N), 2.85 (2H, d, 2J 12.5 Hz, NCH2Ar proximal
to C5H4N), 2.31 (6H, s, 3-C6H2Me2), 2.21 (6H, s, 5-C6H2Me2).
13C{1H} NMR (benzene-d6, 75.5 MHz, 293 K): 160.7 (2-C6H2-
Me2), 157.7 (2-C5H4N), 148.8 (6-C5H4N), 136.8 (4-C5H4N), 131.3
(4-C6H2Me2), 127.9 (6-C6H2Me2), 125.5 (5-C6H2Me2), 124.7 (3-
C6H2Me2), 123.9 (1-C6H2Me2), 121.6 (5-C5H4N), 120.1 (3-
C5H4N), 63.9 (NCH2Ar), 58.5 (NCH2C5H4N), 49.9 (NMe2 trans
to C5H4N), 48.6 (NMe2 cis to C5H4N), 20.7 (5-C6H2Me2), 17.4
(3-C6H2Me2). IR (KBr plates, Nujol mull, cm-1): 2755 (s), 2739
(s), 1603 (s), 1572 (w), 1456 (bs), 1411 (w), 1342 (s), 1319 (s),
1311 (w), 1299 (bs), 1241(w), 1220 (w), 1206 (w), 1159 (m), 1149
(m), 1114 (w), 1101 (w), 964 (s), 949 (s), 901 (w), 887 (w), 857
(m), 844 (m), 832 (s), 821 (s), 766 (w), 757 (m), 748 (w), 729
(m), 682 (w), 643 (m), 627 (m), 588 MB), 558 (s). EIMS: m/z
422 (100%), [M - 2NMe2]+. Anal. Found (calcd for C28H38N4O2-
Ti): C, 65.9 (65.9); H, 7.3 (7.5); N, 10.6 (11.0).
1H NMR (dichloromethane-d2, 300.1 MHz, 293 K): 9.07 (1H,
app. dt, 3J 5.5 Hz, app. 4J 1.0 Hz, 6-C5H4N), 7.58 (1H, app. td,
3
4
3
app. J 7.5 Hz, J 1.5 Hz, 4-C5H4N), 7.16 (1H, app. t, app. J
3
6.5 Hz, 5-C5H4N), 6.98 (1H, s, 4-C6H2Me2 (a)), 6.94 (1H, d, J
8.0 Hz, 3-C5H4N), 6.90 (1H, s, 6-C6H2Me2 (a)), 6.60 (1H, s,
6-C6H2Me2 (b)), 6.52 (1H, s, 4-C6H2Me2 (b)), 5.18 (1H, d, 2J 13.0
2
Hz, NCH2Ar (b)), 4.85 (1H, d, J 15.5 Hz, NCH2C5H4N), 3.89
(1H, d, 2J 13.0 Hz, NCH2Ar (a)), 3.83 (1H, d, 2J 15.5 Hz,
NCH2C5H4N), 3.56 (1H, d, 2J 13.0 Hz, NCH2Ar (b)), 3.04 (1H,
2
d, J 13.0 Hz, NCH2Ar (a)), 2.36 (3H, s, 3-C6H2Me2 (b)), 2.29
(3H, s, 5-C6H2Me2 (b)), 2.05 (3H, s, 5-C6H2Me2 (a)), 2.00 (3H,
s, 3-C6H2Me2 (a)). The designations (a) and (b) relate reso-
nances to protons on a specific phenoxy group. However which
group lies cis and which trans to the pyridyl group could not
be determined. 13C{1H} NMR (dichloromethane-d2, 125.7 MHz,
293 K): 160.9 (2-C6H2Me2 (a)), 157.6 (2-C6H2Me2 (b)), 156.1
(2-C5H4N), 148.4 (6-C5H4N), 139.6 (4-C5H4N), 132.3 (5-C6H2-
Me2 (b)), 131.7 (4-C6H2Me2 (b)), 131.6 (4-C6H2Me2 (a)), 130.4
(5-C6H2Me2 (a)), 127.7 (6-C6H2Me2 (b)), 126.7 (6-C6H2Me2 (a)),
125.8 (1-C6H2Me2 (b)), 124.4 (1-C6H2Me2 (a)), 124.2 (3-C6H2-
Me2 (b)), 123.8 (3-C6H2Me2 (a)), 123.6 (3-C5H4N), 121.8 (5-
C5H4N), 66.0 (NCH2C5H4N), 65.1 (NCH2Ar (b)), 61.2 (NCH2Ar

326 Organometallics, Vol. 24, No. 2, 2005
Boyd et al.
Ti(O2tBuNN′)(NMe2)(S-4-C6H4Me) (13). To a stirred solu-
tion of Ti(O2tBuNN′)(NMe2)2 (11) (0.200 g, 0.295 mmol) in
benzene (20 mL), cooled to 7 °C, was added dropwise a solution
of HS-4-C6H4Me (0.037 g, 0.295 mmol) in benzene (15 mL).
The solution was allowed to warm to room temperature and
then stirred for a further 90 min, after which time the volatiles
were removed under reduced pressure to give crude 13 as an
orange-brown powder. This was washed with pentane (35 mL)
to give a yellow-brown powder, which was dried in vacuo to
yield 13. Yield: 0.116 g (52%).
72.6 (73.5); H, 8.8 (9.1); N, 4.2 (4.5) (the low %C is attributed
to titanium carbide formation).
Ti(O2MeNN′)Me2 (15). To a stirred slurry of Ti(O2MeNN′)-
Cl2 (0.75 g, 1.44 mmol) in toluene (30 mL), cooled to -78 °C,
was added dropwise and in the absence of light a solution of
MeMgBr (1.4 M in toluene/THF, 75:25, 2.06 mL, 2.88 mmol)
in toluene (10 mL). The solution was allowed to warm to room
temperature and stirred for a further 30 min, after which time
dioxane (5 mL) was added. After stirring for a further 5 min
the volatiles were removed under reduced pressure. The
residue was extracted into diethyl ether (2 × 25 mL) and
filtered. This solution was reduced to 10 mL, and hexanes (20
mL) were added. Cooling to -80 °C produced a yellow
microcrystalline powder, which was dried in vacuo to give Ti-
(O2MeNN′)Me2‚nEt2O (11‚nEt2O) (typical value of n ) 0.1).
Yield: 0.221 g (33%). The Et2O content was determined by
3
1H NMR (benzene-d6, 300.1 MHz, 293 K): 9.22 (1H, d, J
5.5 Hz, 6-C5H4N), 8.05 (2H, d, 3J 8.0 Hz, o-SC6H4Me), 7.38 (2H,
d, 4J 2.5 Hz, 4-C6H2 Bu2), 7.08 (2H, d, 3J 8.0 Hz, p-SC6H4Me),
t
4
t
3
6.97 (2H, d, J 2.5 Hz, 6-C6H2 Bu2), 6.33 (1H, app. td, app. J
4
3
7.5 Hz, J 2.0 Hz, 4-C5H4N), 6.17 (1H, app. t, app. J 7.5 Hz,
5-C5H4N), 5.57 (1H, d, 3J 8.0 Hz, 3-C5H4N), 3.93 (2H, d, 2J
12.5 Hz, NCH2Ar distal to C5H4N), 3.36 (6H, s, NMe2), 3.10
(2H, s, NCH2C5H4N), 2.88 (2H, d, 2J 12.5 Hz, NCH2Ar proximal
1
careful integration of the H NMR spectrum.
3
1H NMR (benzene-d6, 300.1 MHz, 293 K): 7.96 (1H, d, J
t
to C5H4N), 2.16 (3H, s, SC6H4Me), 1.68 (18H, s, 3-C6H2 Bu2),
5.0 Hz, 6-C5H4N), 6.78 (2H, s, 4-C6H2Me2), 6.52 (2H, s, 6-C6H2-
1.32 (18H, s, 5-C6H2 Bu2). 13C{1H} NMR (benzene-d6, 75.5
t
Me2), 6.36 (1H, app. td, a 3J 7.5 Hz, app. 4J 1.5 Hz, 4-C5H4N),
t
3
3
MHz, 293 K): 159.6 (2-C6H2 Bu2), 157.2 (2-C5H4N), 150.6 (6-
C5H4N), 143.6 (i-SC6H4Me), 140.2 (p-SC6H4Me), 137.0 (5-C6H2 -
Bu2), 136.8 (4-C5H4N), 133.7 (o-SC6H4Me), 132.3 (3-C6H2 Bu2),
128.2 (o-SC6H4Me), 124.9 (6-C6H2 Bu2), 124.5 (1-C6H2 Bu2),
6.05 (1H, app. t, app. J 6.0 Hz, 5-C5H4N), 5.63 (1H, d, J 8.0
Hz, 3-C5H4N), 3.72 (2H, d, 2J 12.5 Hz, NCH2Ar distal to
C5H4N), 3.00 (2H, s, NCH2C5H4N), 2.69 (2H, d, 2J 12.5 Hz,
NCH2Ar proximal to C5H4N), 2.51 (6H, s, 3-C6H2Me2), 2.12 (6H,
s, 5-C6H2Me2), 1.90 (3H, s, Ti-Me cis to C5H4N), 1.52 (3H, s,
Ti-Me trans to C5H4N). 13C{1H} NMR (benzene-d6, 75.5 MHz,
293 K): 160.8 (2-C6H2Me2), 157.7 (2-C5H4N), 147.4 (6-C5H4N),
136.8 (4-C5H4N), 131.6 (4-C6H2Me2), 127.7 (6-C6H2Me2), 126.9
(5-C6H2Me2), 125.1 (3-C6H2Me2), 124.3 (1-C6H2Me2), 121.8 (5-
C5H4N), 120.2 (3-C5H4N), 62.6 (NCH2Ar), 61.4 (Ti-Me trans
to C5H4N), 59.9 (Ti-Me cis to C5H4N), 59.5 (NCH2C5H4N), 20.8
(5-C6H2Me2), 16.6 (3-C6H2Me2). IR (NaCl plates, Nujol mull,
cm-1): 1606 (m), 1571 (w), 1316 (m), 1305 (s), 1279 (m), 1155
(m), 1056 (s), 1038 (w), 1016 (s), 977 (w), 963 (w), 955 (m), 937
(m), 901 (w), 884 (w), 869 (m), 851 (m), 835 (s), 762 (w), 750
(m), 677 (m), 642 (w), 627 (m), 609 (s). EIMS: m/z 420 (43%),
[M - 2Me, - 2H]+. Anal. Found (calcd for C26H32N2O2Ti‚0.1-
(OEt2)): C, 68.7, (69.0); H, 7.6, (7.3); N, 6.0, (6.1).
t
t
t
t
t
124.1 (4-C6H2 Bu2), 121.6 (5-C5H4N), 119.6 (3-C5H4N), 65.7
(NCH2Ar), 58.3 (NCH2C5H4N), 52.7 (NMe2), 36.2 (3-C6H2-
(CMe3)2), 35.0 (5-C6H2(CMe3)2), 32.7 (5-C6H2(CMe3)2), 31.1 (3-
C6H2(CMe3)2), 21.9 (SC6H4Me). IR (NaCl plates, Nujol mull,
cm-1): 1891 (w), 1869 (w), 1845 (w), 1830 (w), 1793 (w), 1772
(w), 1749 (w), 1734 (w), 1717 (w), 1699 (w), 1684 (w), 1670
(w), 1647 (w), 1636 (w), 1604 (m), 1569 (m), 1559 (w), 1541
(w), 1522 (w), 1507 (w), 1416 (m), 1365 (s), 1306 (s), 1287 (s),
1241 (s), 1203 (m), 1171 (s), 1131 (w), 1055 (w), 1040 (w), 1017
(m), 977 (w), 959 (s), 934 (w), 916 (w), 890 (m), 879 (w), 869
(s), 847 (s), 757 (s), 644 (w), 632 (w), 595 (m). EIMS: m/z 713
(7%), [M - NMe2]+; m/z 634 (100%), [M - SC6H4Me]+. Anal.
Found (calcd for C45H63N3O2STi): C, 71.0 (71.3); H, 8.2 (8.4);
N, 5.6 (5.5).
Ti(O2tBuNN′)Me2 (14). To a stirred slurry of Ti(O2tBuNN′)-
Cl2 (0.750 g, 1.134 mmol) in benzene (30 mL), cooled to 7 °C,
was added dropwise and in the absence of light a solution of
MeMgBr (1.4 M in toluene/THF, 75:25, 1.62 mL, 2.268 mmol).
The solution was allowed to warm to room temperature and
then stirred for 1 h, after which time dioxane (5 mL) was added
to encourage precipitation of magnesium halide salt products.
After stirring for a further 5 min the volatiles were removed
under reduced pressure. The residue was extracted into
pentane (2 × 25 mL), filtered, and concentrated to give 14 as
an off-yellow powder. Yield: 0.256 g (36%).
Ti(O2tBuNN′)(NtBu)(py) (16). To a stirred solution of Ti-
(NtBu)Cl2(py)3 (0.726 g, 1.70 mmol) in pyridine (25 mL), cooled
to 7 °C, was added dropwise a solution of Na2O2tBuNN′ (1.00
g, 1.70 mmol) in pyridine (30 mL). The solution was heated to
80 °C for 2 h, after which time it was allowed to cool to room
temperature. The volatiles were removed under reduced
pressure to give a peach-colored solid. This was extracted into
benzene (100 mL), the volume was reduced to 35 mL, and
pentane (75 mL) was added. Cooling to -30 °C for 16 h
produced a pale peach precipitate, which was washed with cold
pentane (2 × 25 mL) and dried in vacuo to give 16. Yield: 0.603
g (48%). Diffraction-quality crystals were grown from a
saturated benzene solution at room temperature.
3
1H NMR (benzene-d6, 300.1 MHz, 293 K): 7.84 (1H, d, J
8.0 Hz, 6-C5H4N), 7.43 (2H, d, 4J 3.0 Hz, 4-C6H2 Bu2), 6.88 (2H,
t
d, 4J 3.0 Hz, 6-C6H2 Bu2), 6.31 (1H, app. td, app. 3J 7.0 Hz, 4J
1H NMR (benzene-d6, 300 MHz, 293 K): 9.48 (3H, overlap-
t
3
3
1.5 Hz, 4-C5H4N), 6.04 (1H, app. t, app. J 5.5 Hz, 5-C5H4N),
ping 2 × d, app. J 4.4 Hz, 6-C5H4N and 2-C5H5N), 7.47 (2H,
5.58 (1H, d, 3J 8.0 Hz, 3-C5H4N), 3.76 (2H, d, 2J 13.0 Hz, NCH2-
Ar distal to C5H4N), 2.93 (2H, s, NCH2C5H4N), 2.64 (2H, d, 2J
13.0 Hz, NCH2Ar proximal to C5H4N), 1.97 (3H, s, Ti-Me cis
d, 4J 2.5 Hz, 4-C6H2 Bu2), 6.92 (2H, d, 4J 2.5 Hz, 6-C6H2 Bu2),
t
t
3
6.83 (1H, app. t, app. J 6.5 Hz, 4-C5H5N), 6.55 (2H, app. t,
3
3
4
app. J 6.5 Hz, 3-C5H5N), 6.42 (1H, td, J 8.0 Hz, J 1.5 Hz,
4-C5H4N), 6.34 (1H, app. t, app. 3J 6.5 Hz, 5-C5H4N), 5.66 (1H,
d, 3J 8.0 Hz, 3-C5H4N), 3.59 (2H, d, 2J 12.0 Hz, NCH2Ar distal
to C5H4N), 3.17 (2H, s, NCH2C5H4N), 2.62 (2H, d, 2J 12.0 Hz,
t
to C5H4N), 1.83 (18H, s, 3-C6H2 Bu2), 1.57 (3H, s, Ti-Me trans
t
to C5H4N), 1.40 (18H, s, 5-C6H2 Bu2). 13C{1H} NMR (benzene-
t
d6, 75.5 MHz, 293 K): 160.9 (2-C6H2 Bu), 157.8 (2-C5H4N),
t
t
148.4 (6-C5H4N), 140.3 (5-C6H2 Bu2), 136.9 (4-C5H4N), 135.9
NCH2Ar proximal to C5H4N), 1.95 (18H, s, 3-C6H2 Bu2), 1.42
(3-C6H2 Bu2), 125.6 (1-C6H2 Bu2), 124.8 (6-C6H2 Bu2), 124.0 (4-
(18H, s, 5-C6H2 Bu2), 1.39 (9H, s, NtBu). 13C{1H} NMR
t
t
t
t
t
t
C6H2 Bu2), 121.4 (5-C5H4N), 120.1 (3-C5H4N), 63.7 (NCH2Ar
(benzene-d6, 75.5 MHz, 293 K): 162.6 (2-C6H2 Bu2), 158.3 (2-
C5H4N), 154.2 (2-C5H5N), 151.4 (6-C5H4N), 137.6 (5-C6H2 Bu2),
137.0 (4-C5H4N), 136.9 (3-C6H2 Bu2), 124.9 (6-C6H2 Bu2), 124.0
(3-C5H5N), 123.6 (4-C6H2 Bu2), 120.8 (5-C5H4N), 120.1 (3-
t
and Ti-Me cis to C5H4N), 61.9 (Ti-Me trans to C5H4N), 58.9
(NCH2C5H4N), 35.9 (3-C6H2(CMe3)2), 34.7 (5-C6H2(CMe3)2),
32.4 (5-C6H2(CMe3)2), 30.7 (3-C6H2(CMe3)2). IR (NaCl plates,
Nujol mull, cm-1): 1732 (bw), 1603 (s), 1568 (w), 1414 (s), 1362
(m), 1304 (m), 1287 (s), 1239 (s), 1203 (s), 1169 (w), 1129 (w),
1155 (w), 1025 (w), 1012 (w) 977 (w), 931 (w), 915 (m), 882
(m), 857 (s), 847 (s), 772 (w), 760 (s), 725 (m), 629 (w), 598 (w).
EI-HRMS: m/z found (calcd for C37H53N2O2Ti, [M - Me]+)
605.3586 (605.3587). Anal. Found (calcd for C38H56N2O2Ti): C,
t
t
t
C5H4N), 67.6 (NCMe3), 63.9 (NCH2Ar), 56.7 (NCH2C5H4N),
36.3 (3 C6H2(CMe3)2), 34.6 (5 C6H2(CMe3)2), 33.0 (NCMe3), 32.6
t
(5 C6H2(CMe3)2), 31.0 (3 C6H2(CMe3)2), 1-C6H2 Bu2 and 4-C5H5N
not observed, possibly obscured or overlapping with solvent
or other compound resonances. IR (NaCl plates, Nujol mull,
cm-1): 1956 (w), 1870 (w), 1845 (w), 1773 (w), 1750 (w), 1734

Diamino-bis(phenolate) Ti, Sc, and Y Complexes
Organometallics, Vol. 24, No. 2, 2005 327
(w), 1717 (w), 1699 (w), 1685 (w), 1670 (w), 1654 (w), 1646
(w), 1637 (w), 1606 (s), 1568 (m), 1541 (w), 1522 (w), 1416 (s),
1364 (s), 1346 (s), 1318 (s), 1304 (w), 1293 (s), 1240 (w), 1205
(m), 1168 (s), 1152 (w), 1132 (w), 1114 (m), 1104 (w), 1054 (w),
1038 (m), 1021 (w), 1011 (w), 976 (s), 947 (w), 934 (m), 914
(m), 895 (w), 880 (s), 842 (s), 799 (s), 780 (s), 764 (m), 749 (m),
703 (s), 679 (s), 647 (s). EIMS: m/z 590 (22%), [M - NtBu, -
C5H5N]+. Anal. Found (calcd for C45H64N4O2Ti): C, 73.5 (73.0);
H, 8.3 (8.7); N, 7.4 (7.6).
a pale yellow-green powder, which was recrystallized from
dichloromethane/hexanes (5:10 mL) at -80 °C to give 18.
Yield: 0.057 g (33%). Diffraction-quality crystals were grown
from a saturated dichloromethane solution at room tempera-
ture.
1H NMR (dichloromethane-d2, 300.1 MHz, 293 K): 8.66 (2H,
d, 3J 4.5 Hz, 6-C5H4N), 7.23 (2H, atd, a 3J 7.5 Hz, a4J 1.0 Hz,
4-C5H4N), 7.04 (2H, d, 4J 2.0 Hz, 6-C6H2 Bu2 (a)), 6.93 (2H, d,
t
4J 2.0 Hz, 4-C6H2 Bu2 (a)), 6.88 (2H, d, J 8.0 Hz, 3-C5H4N),
6.72 (2H, at, a 3J 7.0 Hz, 5-C5H4N), 6.67 (2H, d, 4J 2.5 Hz,
t
3
Ti(O2tBuNN′)(N-2,6-C6H3Me2)(py) (17). To a stirred solu-
tion of Ti(N-2,6-C6H3Me2)Cl2(py)3 (0.807 g, 1.70 mmol) in
pyridine (30 mL), cooled to 7 °C, was added dropwise a solution
of Na2O2tBuNN′ (1.00 g, 1.70 mmol) in pyridine (30 mL). The
solution was heated to 80 °C for 2 h, after which time it was
allowed to cool to room temperature. The volatiles were
removed under reduced pressure to give an orange-brown solid,
which was extracted in benzene (30 mL) and filtered. Pentane
(25 mL) was added, and subsequent cooling to -30 °C for 4
days produced an orange-brown precipitate, from which the
mother liquor was decanted. The orange-brown powder was
washed with cold pentane (2 × 25 mL) and dried in vacuo to
give 17. Yield: 1.078 g (80%).
t
4
t
6-C6H2 Bu2 (b)), 6.49 (2H, d, J 2.5 Hz, 4-C6H2 Bu2 (b)), 4.79
(4H, m, NCH2Ar (f) and NCH2C5H4N), 3.58 (2H, d, 2J 14.0 Hz,
NCH2C5H4N), 3.39 (2H, d, 2J 13.0 Hz, NCH2Ar (e)), 3.21 (2H,
d, J 12.0 Hz, NCH2Ar (f)), 2.58 (2H, d, J 13.0 Hz, NCH2Ar
(e)), 1.30 (18H, s, 3-C6H2 Bu2 (b)), 1.23 (18H, s, 5-C6H2 Bu2 (b)),
1.06 (18H, s, 3-C6H2 Bu2 (a)), 0.91 (18H, s, 5-C6H2 Bu2 (a)), the
designations (a) and (b), (c) and (d), and (e) and (f) relate pairs
of resonances to protons on specific phenoxy groups. However
which group lies cis, and which trans, to the pyridyl group
could not be determined. 13C{1H} NMR (dichloromethane-d2,
75.5 MHz, 293 K): 161.2 (2-C6H2 Bu2), 159.1 (2-C6H2 Bu2),
156.6 (2-C5H4N), 151.6 (6-C5H4N), 139.7 (5-C6H2 Bu2 (a)), 138.4
2
2
t
t
t
t
t
t
t
t
t
1H NMR (benzene-d6, 300.1 MHz, 293 K): 9.36 (2H, bs,
2-C5H5N), 9.19 (1H, d, 3J 4.0 Hz, 6-C5H4N), 7.39 (2H, d, 4J 2.5
(5-C6H2 Bu2 (b)), 137.9 (4-C5H4N), 136.1 (3-C6H2 Bu2 (b)), 134.3
(3-C6H2 Bu2 (a)), 126.0 (1-C6H2 Bu2), 125.8 (1-C6H2 Bu2), 124.8
(4-C6H2 Bu2 (c)), 124.0 (4-C6H2 Bu2 (d)), 123.7 (6-C6H2 Bu2 (c)),
122.7 (5-C5H4N), 122.4 (6-C6H2 Bu2 (d)), 121.4 (3-C5H4N), 64.0
t
t
t
t
t
t
Hz, 4-C6H2 Bu2), 7.07 (2H, d, 3J 7.5 Hz, m-C6H3Me2), 6.80-
t
t
t
6.65 (4H, overlapping m, 6-C6H2 Bu2, p-C6H3Me2 and 4-C5H5N),
3
4
(NCH2C5H4N), 62.3 (NCH2Ar (f)), 59.2 (NCH2Ar (e)), 35.1 (3-
C6H2(CMe3)2 (a or b)), 35.0 (3-C6H2(CMe3)2 (b or a)), 34.3 (5-
C6H2(CMe3)2 (b)), 33.9 (5-C6H2(CMe3)2 (a)), 31.8 (5-C6H2(CMe3)2
(b)), 31.7 (5-C6H2(CMe3)2 (a)), 30.3 (3-C6H2(CMe3)2 (b)), 30.2 (3-
C6H2(CMe3)2 (a)). IR (NaCl plates, Nujol mull, cm-1): 1869 (w),
1845 (w), 1830 (w), 1793 (w), 1772 (w), 1749 (w), 1734 (w),
1717 (w), 1699 (w), 1684 (w), 1670 (w), 1654 (w), 1636 (w),
1609 (m), 1576 (w), 1559 (w), 1542 (w), 1522 (w), 1508 (w),
1414 (m), 1340 (w), 1325 (w), 1291 (m), 1277 (s), 1242 (s), 1203
(m), 1170 (s), 1153 (w), 1134 (m), 1100 (m), 1026 (s), 977 (m),
916 (w), 876 (m), 861 (w), 840 (s), 778 (s), 767 (vs), 755 (s),
747 (s), 724 (m), 699 (w), 649 (m). EIMS: m/z 1212 (4%), [M]+;
m/z 606 (49%), [1/2 M]+. Anal. Found (calcd for C72H100N4O6-
Ti2): C, 71.2 (71.3); H, 8.5 (8.3); N, 4.5 (4.6).
6.50 (1H, td, J 7.5 Hz, J 2.0 Hz, 4-C5H4N), 6.42 (2H, app. t,
app. 3J 6.5 Hz, 3-C5H5N), 6.19 (1H, app. t, app. 3J 7.0 Hz,
5-C5H4N), 5.83 (1H, d, 3J 7.5 Hz, 3-C5H4N), 3.41 (2H, d, 2J
12.5 Hz, NCH2Ar distal to C5H4N), 3.12 (2H, s, NCH2C5H4N),
2.68 (6H, s, N-2,6,-C6H3Me2), 2.52 (2H, d, 2J 13.0 Hz, NCH2Ar
t
proximal to C5H4N), 1.84 (18H, s, 3-C6H2 Bu2), 1.36 (18H, s,
5-C6H2 Bu2) 13C{1H} NMR (benzene-d6, 75.5 MHz, 293 K):
t
t
162.6 (2-C6H2 Bu2), 159.0 (i-C6H3Me2), 158.4 (2-C5H4N), 153.4
t
(2-C5H5N), 151.0 (6-C5H4N), 137.9 (5-C6H2 Bu2 and 4-C5H4N),
t
137.0 (3-C6H2 Bu2), 131.7 (o-C6H3Me2), 128.3 (p-C6H3Me2),
t
127.9 (m-C6H3Me2), 124.4 (6-C6H2 Bu2 and 3-C5H5N), 123.4 (4-
t
C6H2 Bu2), 121.2 (3- and 5-C5H4N), 118.1 (4-C5H5N), 63.7
(NCH2Ar), 57.8 (NCH2C5H4N), 35.9 (3-C6H2(CMe3)2), 34.1 (5-
C6H2(CMe3)2), 32.2 (5-C6H2(CMe3)2), 30.6 (3-C6H2(CMe3)2), 20.5
NMR Tube Scale Reaction of Ti(O2tBuNN′)(NtBu)(py)
(16) with CO2. A solution of Ti(O2tBuNN′)(NtBu)(py) (16) (0.010
g, 0.014 mmol) in benzene-d6 (0.75 mL) was transferred to a 5
mm J. Young NMR tube. The solution was degassed by three
freeze-pump-thaw cycles before addition of CO2 (1 atm) to
the solution at room temperature. After 1 h, the 1H NMR
spectrum showed that the major products (>95% by integral)
t
(N-2,6,-C6H3Me2), 1-C6H2 Bu2 not observed, possibly obscured
or overlapping with solvent or other compound resonances. IR
(NaCl plates, Nujol mull, cm-1): 1606 (s), 1586 (w), 1570 (w),
1412 (m), 1284 (s), 1214 (s), 1203 (m), 1167 (s), 1155 (m), 1134
(m), 1117 (m), 1106 (w), 1070 (m), 1056 (m), 1041 (m), 1023
(s), 1014 (s), 977 (m), 954 (m), 936 (w), 914 (m), 889 (w), 873
(m), 847 (s), 837 (s), 764 (m), 756 (s), 702 (s), 679 (s), 648 (m),
635 (w). EIMS: m/z 679 (19%), [M - C5H5N, - 2Me]+; m/z
590 (35%), [M - C5H5N, - NC6H3Me2]+. Anal. Found (calcd
for C49H64N4O2Ti): C, 74.9 (74.6); H, 8.2 (8.2); N, 6.1 (7.1) (the
low %N is attributed to titanium nitride formation as is well-
known for imidotitanium compounds42).
Alternative NMR Tube Scale Synthesis of Ti(O2tBuNN′)-
(N-2,6-C6H3Me2)(py) (17). To an orange-brown solution of Ti-
(O2tBuNN′)(NtBu)(py) (16) (0.020 g, 0.027 mmol) in benzene-
d6 (0.75 mL) in a 5 mm J. Young NMR tube was added 2,6-
dimethylaniline (0.0033 g, 0.027 mmol). After heating for 6
days at 80 °C an 1H NMR spectrum confirmed that the reaction
had proceeded quantitatively to give 17 and H2NtBu.
Ti2(O2tBuNN′)2(µ-O)2 (18). To a stirred orange-brown solu-
tion of Ti(O2tBuNN′)(NtBu)(py) (16) (0.200 g, 0.270 mmol) in
benzene (20 mL) cooled to 7 °C was added dropwise a solution
of water in THF (1.00 M, 0.270 mL, 0.270 mmol), further
dispersed in benzene (15 mL). During the addition the solution
turned lime green in color. It was subsequently allowed to
warm to room temperature and stirred for a further 30 min.
The volatiles were removed under reduced pressure to leave
t
were 18 and BuNCO.
NMR Tube Scale Reaction of Ti(O2tBuNN′)(N-2,6-
C6H3Me2)(py) (17) with CO2. A solution of Ti(O2tBuNN′)(N-
2,6-C6H3Me2)(py) (17) (0.011 g, 0.014 mmol) in benzene-d6 (0.75
mL) was transferred to a 5 mm J. Young NMR tube. The
solution was degassed by three freeze-pump-thaw cycles
before addition of CO2 (1 atm) to the solution at room
temperature. After 1 h, the 1H NMR spectrum showed that
the major products (>95%) were 18 and ArNCO (Ar ) 2,6-
C6H3Me2).
Ti(O2tBuN)(NtBu)(py) (19). To a stirred solution of Ti(Nt-
Bu)Cl2(py)3 (0.40 g, 0.93 mmol) in THF (20 mL) was added a
stirred solution of Na2O2tBuN (0.50 g, 0.93 mmol) in THF (20
mL), and the resulting solution was stirred at 60 °C for 16 h.
Volatiles were removed under reduced pressure and the
residues extracted into pentane (30 mL) and cooled to -80 °C.
The pale orange product 19 was washed with -80 °C pentane
(10 mL) and dried in vacuo. Yield: 0.017 g, (3%).
Note: the compound exists as a mixture of two isomers
1
formed in a ratio of 2:1. Only H NMR characterization was
carried out on this compound, which was obtained in small
1
quantities. H NMR (C6D6, 300.0 MHz, 293 K): 9.18 (2H, m,
(42) See the following and references therein: Carmalt, C. J.;
Newport, A.; Parkin, I. P.; Mountford, P.; Sealey, A. J.; Dubberley, S.
R. J. Mater. Chem. 2003, 13, 84.
t
2-C5H5N), 9.10 (2H, m, 2-C5H5N), 7.57 (4H, d, 4 and 6-C6H2 -
Bu2) 2 overlapping, 7.23 (2H, d, 4J 2.3 Hz, 4/6-C6H2 Bu2), 7.05
t

328 Organometallics, Vol. 24, No. 2, 2005
Boyd et al.
and 6-C6H2 Bu2) 2 overlapping doublets, 7.12 (2H, d, 4J 2.9
(2H, d, 4J 2.9 Hz, 4/6-C6H2 Bu2), 6.93 (2H, m, 4-C5H5N) 2
t
t
t
i
overlapping, 6.65 (4H, m, 3-C5H5N) 2 overlapping, 5.53 (2H,
Hz 4/6-C6H2 Bu2), 7.08 (4H, m, 3-N-2,6-C6H3 Pr2) 2 overlapping,
d, 2J 13.5 Hz, CH2C6H2 Bu2), 3.97 (2H, d, 2J 13.5 Hz, CH2C6H2 -
7.05 (2H, d, 4J 2.9 Hz, 4/6-C6H2 Bu2), 6.88 (4H, m, 4-N-2,6-
t
t
t
2
t
2
i
Bu2), 3.77 (2H, d, J 14.0 Hz, CH2C6H2 Bu2), 3.62 (2H, d, J
C6H3 Pr2 and 4-C5H5N), 6.56 (2H, m, 3-C5H5N), 6.48 (2H, m,
t
2
t
13.5 Hz, CH2C6H2 Bu2), 3.46 (2H, m, CH2CH2CH3), 2.58 (2H,
3-C5H5N), 4.94 (2H, d, J ) 14.7 Hz CH2C6H2 Bu2), 4.76 (1H,
m, CH2CH2CH3), 1.46 (20H, d, C6H2 Bu2 and CH2CH2CH3),
sep, 2-N-2,6-C6H3(HiPr2), 4.46 (1H, sep, 2-N-2,6-C6H3(HiPr2),
t
1.40 (20H, d, C6H2 Bu2 and CH2CH2CH3), 1.20 (9H, s, NtBu),
4.10 (2H, d, 2J 14.7 Hz, CH2C6H2 Bu2), 3.85 (2H, d, 2J 14.7
t
t
3
t
t
1.08 (9H, s, NtBu), 0.52 (3H, t, J 7.0 Hz, CH2CH2CH3), 0.20
Hz, CH2C6H2 Bu2), 3.65 (2H, d, 2J 14.7 Hz, CH2C6H2 Bu2), 3.27
(2H, m, CH2CH2CH3), 2.87 (2H, m, CH2CH2CH3), 1.47 (36H,
3
(3H, t, J 7.0 Hz, CH2CH2CH3).
t
t
Ti(O2tBuN)(N-2,6-C6H3Me2)(py) (20). To a stirred solution
of Ti(N-2,6-C6H3Me2)Cl2(py)3 (0.81 g, 2.78 mmol) in THF (20
mL) was added a stirred solution of Na2O2tBuN (1.50 g, 2.78
mmol) in THF (20 mL) and the resulting solution stirred under
partial reduced pressure at 60 °C for 16 h. Volatiles were
removed under reduced pressure and the residues extracted
into pentane/dichloromethane (9:1 v/v; 30 mL) and cooled to
-80 °C. The orange solid product 20 was washed with -80 °C
pentane (10 mL) and dried in vacuo. Yield: 0.93 g (45%).
Diffraction-quality crystals of 2 were grown from a saturated
benzene solution.
d, 3-C6H2 Bu2), 1.42 (36H, d, 5-C6H2 Bu2), 1.31 (16H, m, 2-N-
2,6-C6H3 Pr2 and CH2CH2CH3) 2 overlapping, 1.12 (12H, m,
i
i
3
2-N-2,6-C6H3 Pr2), 0.42 (3H, t, J 7.1 Hz, CH2CH2CH3), 0.24
(3H, t, 3J 7.1 Hz, CH2CH2CH3). 13C{1H} NMR (C6D6, 75.5 MHz,
t
t
293 K): 160.4 (2-C6H2 Bu2), 160.3 (2-C6H2 Bu2), 156.3 (1-N-
i
i
2,6-C6H3 Pr2), 155.7 (1-N-2,6-C6H3 Pr2), 150.9 (2-C5H5N), 150.3
(2-C5H5N), 144.6 (5-C6H2 Bu2), 144.3 (5-C6H2 Bu2), 139.4 (4-
C5H5N), 139.2 (4-C5H5N), 139.0 (1-C6H2 Bu2) 2 overlapping,
136.3 (3-C6H2 Bu2) 2 overlapping, 124.8 (3-C5H5N) 2 overlap-
ping, 124.4 (4/6-C6H2 Bu2), 124.3 (4/6-C6H2 Bu2), 124.2 (4/6-
C6H2 Bu2), 123.4 (4-N-2,6-C6H3 Pr2), 123.1 (4-N-2,6-C6H3 Pr2),
60.4 (CH2C6H2 Bu2), 58,2 (CH2CH2CH3), 58.1 (CH2C6H2 Bu2),
49.4 (CH2CH2CH3), 35.1 (3-C6H2(CMe3)2), 35.0 (5-C6H2(CMe3)2),
34.4 (5-C6H2(CMe3)2), 34.3 (3-C6H2(CMe3)2), 32.0 (3-C6H2 Bu2)
t
t
t
t
t
t
t
i
i
t
t
Note: the compound exists as a mixture of two isomers
formed in a ratio of 3:1. The actual ratio depends on the
individual preparation. 1H NMR (C6D6, 300.0 MHz, 293 K):
8.80 (2H, m, 2-C5H5N), 8.76 (2H, m, 2-C5H5N), 7.56 (4H, d, 4
t
t
t
2 overlapping, 30.1 (5-C6H2 Bu2), 29.9 (5-C6H2 Bu2), 27.4 (2-
N-2,6-C6H3(CiPr2)), 27.1 (2-N-2,6-C6H3(CiPr2)), 24.6 (2-N-2,6-
and 6 C6H2 Bu2) 2 overlapping doublets, 7.14 (2H, d, 4J 2.3
t
i
t
t
C6H3 Pr2) 2 overlapping, 15.0 (CH2CH2CH3), 13.4 (CH2CH2-
Hz, 4-C6H2 Bu2), 7.03 (4H, m, 6-C6H2 Bu2 and 3-C6H3Me2), 6.93
(2H, d, 3J 7.6 Hz, 3-C6H3Me2), 6.80 (2H, m, 4-C5H5N) 2
overlapping, 6.71 (2H, m, 4-C6H3Me2) 2 overlapping, 6.45 (4H,
CH3), 11.7 (CH2CH2CH3), 11.3 (CH2CH2CH3). Note: 4/6-
C6HtBu2, 3-N-2,6-C6H3 Pr2 (2 overlapping), and 2-N-2,6-
i
i
m, 3-C5H5N) 2 overlapping, 5.11 (2H, d, 2J 14.1 Hz, CH2C6H2 -
t
C6H3 Pr2 (2 overlapping) all obscured by solvent resonance. IR
(KBr pellet, cm-1): 2956 (s), 2904 (s), 2866 (s), 2708 (w), 1606
(m), 1582 (w), 1476 (s), 1446 (s), 1360 (m), 1338 (s), 1238 (m),
1216 (m), 1098 (w), 1044 (m), 1016 (w), 988 (m), 844 (s), 806
(m), 754 (s), 640 (m), 570 (s), 546 (w), 514 (s). EIMS: m/z 542
(8%), [M - py - NAr]+.
2
t
2
Bu2), 4.03 (2H, d, J 13.5 Hz, CH2C6H2 Bu2), 3.74 (2H, d, J
14.1 Hz, CH2C6H2 Bu2), 3.62 (2H, d, 2J 14.1 Hz, CH2C6H2 Bu2),
3.27 (2H, m, CH2CH2CH3), 2.77 (2H, m, CH2CH2CH3), 2.73
(6H, s, 2-N-2.6-C6H3Me2), 2.52 (6H, s, 2-N-2,6-C6H3Me2), 1.48
t
t
t
t
(38H, d, 3-C6H2 Bu2 and CH2CH2CH3), 1.42 (38H, d, 5-C6H2 Bu2
NMR Tube Scale Reaction of Ti(O2tBuN)(N-2,6-C6H3Me2)-
(py) (20) with CO2. A solution of Ti(O2tBuN)(N-2,6-C6H3Me2)-
(py) (20) (10 mg, 0.013 mmol) in benzene-d6 was exposed to
CO2 at a pressure of 1.02 atm via a Schlenk line. The reaction
3
and CH2CH2CH3), 0.41 (3H, t, J 7.6 Hz, CH2CH2CH3), 0.25
(3H, t, 3J 7.6 Hz, CH2CH2CH3). 13C{1H} NMR (C6D6, 75.5 MHz,
t
t
293 K): 160.7 (2-C6H2 Bu2), 160.6 (2-C6H2 Bu2), 159.1 (1-N-
2,6-C6H3Me2) 2 overlapping, 150.6 (2-C5H5N), 150.3 (2-C5H5N),
1
t
was monitored using H NMR spectroscopy over a period of
139.2 (4-C5H5N), 139.1 (4-C5H5N), 139.0 (5-C6H2 Bu2) 2 over-
t
t
t
48 h. A red solid precipitated out of the orange solution during
lapping, 136.2 (1-C6H2 Bu2), 136.1 (1-C6H2 Bu2), 133.7 (3-C6H2 -
1
t
t
this time and was analyzed by H NMR spectroscopy (dichlo-
Bu2), 133.2 (3-C6H2 Bu2), 125.0 (4/6-C6H2 Bu2), 124.5 (3-C5H5N),
124.3 (3-C5H5N), 124.2 (4/6-C6H2 Bu2), 123.5 (4/6-C6H2 Bu2),
123.2 (4/6-C6H2 Bu2), 120.9 (4-N-2,6-C6H3Me2) 2 overlapping,
60.4 (CH2C6H2 Bu2), 58.2 (CH2CH2CH3), 50.8 (CH2C6H2 Bu2),
48.8 (CH2CH2CH3), 35.1 (5-C6H2(CMe3)2), 35.0 (5-C6H2(CMe3)2),
t
t
romethane-d2). The spectrum showed a series of unidentifiable
peaks, none of which correspond to the desired product.
Attempts to obtain a clean product on scale-up were equally
unsuccessful.
t
t
t
t
[Ti2(O2tBuNN′)2Me2]‚2[MeB(ArF)3] (22-[MeB(ArF)3]). To a
stirred solution of Ti(O2tBuNN′)Me2 (14) (0.200 g, 0.323 mmol)
in dichloromethane (20 mL) cooled to -78 °C was added
dropwise a solution of B(ArF)3 (0.165 g, 0.323 mmol) in
dichloromethane (5 mL). The resulting orange-red solution was
allowed to stir for a further 15 min at -78 °C before warming
to 0 °C. The solution was concentrated to 5 mL, and hexanes
(10 mL) were added. After cooling to -78 °C for 2 h a red oil
separated. The supernatant was decanted away and the oil
washed with hexanes (3 × 10 mL) and dried in vacuo to give
22-[MeB(ArF)3] as a red solid. Yield: 0.332 g (91%).
34.4 (3-C6H2(CMe3)2), 34.3 (3-C6H2(CMe3)2), 32.1 (3-C6H2 Bu2
t
t
t
& 5-C6H2 Bu2), 30.1 (5-C6H2 Bu2), 29.9 (3-C6H2 Bu2), 20.1 (2-
N-2,6-C6H3Me2), 19.3 (2-N-2,6-C6H3Me2), 14.9 (CH2CH2CH3),
13.5 (CH2CH2CH3), 11.5 (CH2CH2CH3), 11.3 (CH2CH2CH3).
Note: (2-N-2,6-C6H3Me2) 2 overlapping and (3-N-2,6-C6H3Me2)
2 overlapping, both obscured by the solvent resonance. IR (KBr
pellet, cm-1): 12952 (s), 2902 (s), 2868 (m), 1604 (m), 1476
(s), 1444 (s), 1412 (m), 1392 (w), 1266 (s), 1240 (s), 1204 (m),
1170 (m), 1132 (w), 1092 (w), 1042 (w), 916 (w), 848 (s), 756
(s), 698 (m), 638 (w), 620 (w), 472 (w). EIMS: m/z 660 (60%),
[M - py]+. Anal. Found (calcd for C46H65N3O2Ti‚0.1(CH2Cl2)):
C 74.0 (74.0), H 8.9 (8.8), N 5.4 (5.6).
1H NMR (dichloromethane-d2, 500.0 MHz, 183 K): 8.71 (2H,
i
Ti(O2tBuN)(N-2,6-C6H3 Pr2)(py) (21). To a stirred solution
3
s, 6-C5H4N), 8.21 (2H, app. t, app. J 7.0 Hz, 4-C5H4N), 7.70
i
(2H, br s, 5-C5H4N), 7.65 (2H, d, 3J 7.0 Hz, 3-C5H4N), 7.24 (2H,
of Ti(N-2,6-C6H3 Pr2)Cl2(py)3 (0.59 g, 1.11 mmol) in THF (20
mL) was added a stirred solution of Na2O2tBuN (0.60 g, 1.11
mmol) in THF (20 mL) and the resulting solution stirred under
partial reduced pressure at 60 °C for 16 h. Volatiles were
removed under reduced pressure and the residues extracted
into pentane/dichloromethane (9:1 v/v; 30 mL) and cooled to
-80 °C. The pale orange product 21 was washed with -80 °C
pentane (10 mL) and dried in vacuo. Yield: 0.18 g (21%). A
small quantity of diffraction-quality crystals of 21 was also
isolated from this reaction.
t
t
s, 4-C6H2 Bu2 (a)), 7.22 (2H, s, 4-C6H2 Bu2 (b)), 7.08 (2H, s,
6-C6H2 Bu2 (b)), 7.04 (2H, s, 6-C6H2 Bu2 (a)), 4.57 (2H, d, 2J
16.5 Hz, NCH2Ar (a or b)), 4.36 (2H, d, 2J 13.5 Hz, NCH2C5H4N),
3.81 (4H, overlapping d, app. J 15.0 Hz, NCH2Ar (a and b)),
3.52-3.42 (4H, overlapping m, app. J 12.0 Hz, NCH2C5H4N
and NCH2Ar (a or b)), 2.24 (6H, s, Ti-Me), 1.35 (36H, overlap-
t
t
2
3
t
t
ping s, 3-C6H2 Bu2 (a and b)), 1.14 (18H, s, 5-C6H2 Bu2 (a or
b)), 1.10 (18H, s, 5-C6H2 Bu2 (a or b)), 0.28 (6H, s, (C6F5)3BMe).
t
The designations (a) and (b) relate resonances to protons on a
specific phenoxy group. However, which group lies cis, and
which trans, to the pyridyl group could not be determined. 13C-
{1H} NMR (dichloromethane-d2, 125.7 MHz, 183 K): 159.8 (2-
Note: the compound exists as a mixture of two isomers
1
formed in a ratio of 3:2. H NMR (C6D6, 300.0 MHz, 293 K):
8.84 (2H, m, 2-C5H5N), 8.80 (2H, m, 2-C5H5N), 7.54 (4H, m, 4-

Diamino-bis(phenolate) Ti, Sc, and Y Complexes
Organometallics, Vol. 24, No. 2, 2005 329
Table 11. X-ray Data Collection and Processing Parameters for Sc(O2tBuNN′)Cl(py)‚C6H6 (2‚C6H6),
Sc2(O2MeNN′)2Cl2‚2CH2Cl2 (3‚2CH2Cl2), Y2(O2tBuNN′)2(µ-Cl)2(py)2‚3(C6H6) (4‚3C6H6), Ti(O2tBuNN′)(NMe2)2 (11),
Ti(O2tBuNN′)Cl2‚0.5CH2Cl2 (9‚0.5CH2Cl2), Ti(O2MeNN′)Cl2‚2.5C6H6 (10‚2.5C6H6), Ti(O2tBuNN′)(NtBu)(py)‚2C6H6
(16‚2C6H6), Ti2(O2tBuNN′)2(µ-O)2‚3CH2Cl2 (18‚3CH2Cl2), Ti(O2tBuN)(N-2,6-C6H3Me2)(py)‚0.5C6H6 (20‚0.5C6H6),
i
and Ti(O2tBuN)(N-2,6-C6H3 Pr2)(py) (21)
2‚C6H6
3‚2CH2Cl2
4‚3C6H6
9‚0.5CH2Cl2
empirical formula
C41H55Cl1N3O2Sc1‚
C6H6
C48H52Cl2N4O4Sc2‚
2(CH2Cl2)
1079.65
C82H110Cl2N6O4Y2‚
3(C6H6)
1726.88
150
0.71073
P1h
14.4214(3)
17.2881(3)
22.0078(6)
107.2666(6)
106.5164(7)
91.0214(8)
4992.1(2)
2
C36H50Cl2N2O2Ti‚
0.5(CH2Cl2)
704.08
fw
780.43
temp/K
wavelength/Å
space group
a/Å
150
0.71073
C2/c
27.0551(8)
17.8450(5)
19.0419(8)
90
95.537(1)
90
9150.5(5)
8
1.130
0.261
R1 ) 0.0667
150
150
0.71073
P1h
0.71073
C2/c
27.2581(5)
13.1736(3)
24.6155(7)
90
122.040(1)
90
7492.7(3)
8
11.7034(1)
12.0006(1)
18.5464(2)
89.9518(6)
84.0259(6)
88.0933(5)
2589.21(4)
2
b/Å
c/Å
R/deg
â/deg
γ/deg
V/Å3
Z
d(calcd)/Mg‚m-3
abs coeff/mm-1
R indices R1, Rw
[I>3σ(I)]a
1.385
0.618
R1 ) 0.0387
1.15
1.26
R1 ) 0.0762
1.243
0.475
R1 ) 0.0698
Rw ) 0.0882
10‚2.5C6H6
Rw ) 0.0398
Rw ) 0.0629
Rw ) 0.0842
18‚3CH2Cl2
11
16‚2C6H6
empirical formula
C24H26Cl2N2O2Ti‚
2.5(C6H6)
688.57
C40H62N4O2Ti
C45H64N4O2Ti‚2(C6H6)
C72H100N4O6Ti2‚
3(CH2Cl2)
1468.21
150
0.71073
P1h
13.4550(2)
15.6131(2)
20.7997(3)
95.4649(5)
96.8717(6
113.9600(6)
3914.1(1)
2
fw
678.86
150
0.71073
P1h
10.1066(3)
10.1244(3)
19.6020(8)
104.228(1)
97.719(1)
95.997(2)
1906.8(1)
2
897.16
150
0.71073
P1h
10.9050(2)
15.6222(3)
16.7849(4)
98.2396(7)
106.5212(8)
102.9245(9)
2605.6(1)
2
temp/K
wavelength/Å
space group
a/Å
150
0.71073
P21/n
15.7447(7)
9.0987(4)
24.792(2)
90
92.451(2)
90
3548.4(4)
4
b/Å
c/Å
R/deg
â/deg
γ/deg
V/Å3
Z
d(calcd)/Mg‚m-3
abs coeff/mm-1
R indices R1, Rw
[I>3σ(I)]a
1.29
0.42
R1 ) 0.0581
1.18
0.26
R1 ) 0.0528
1.14
0.21
R1 ) 0.0668
1.246
0.459
R1 ) 0.0479
Rw ) 0.0641
Rw ) 0.0480
20‚0.5C6H6
Rw ) 0.0725
Rw ) 0.0520
21
empirical formula
C
46H79N3O2Ti‚0.5C6H6
C50H73N3O2Ti
796.05
150
0.71073
P21/n
11.4403(2)
16.7426(2)
25.1924(3)
90
90.9770(6)
90
4824.7(2)
4
fw
783.03
150
temp/K
wavelength/Å
space group
a/Å
0.71073
P21/c
13.0792(2)
34.8093(3)
11.2256(2)
90
112.2147(4)
90
4731.4(1)
4
b/Å
c/Å
R/deg
â/deg
γ/deg
V/Å3
Z
d(calcd)/Mg‚m-3
abs coeff/mm-1
R indices R1, Rw
[I>3σ(I)]a
1.099
0.219
R1 ) 0.0390
1.096
0.216
R1 ) 0.0415
Rw ) 0.0408
Rw ) 0.0489
2
a R1 ) ∑||Fo| - |Fc||/∑|Fo|; Rw ) {∑w(|Fo| - |Fc|)2/∑(w|Fo| }1/2
.
t
t
C6H2 Bu2 (a)), 159.3 (2-C5H4N), 157.9 (2-C6H2 Bu2 (b)), 152.5
C6H2(CMe3)2 (a and b)), 34.0 (5-C6H2(CMe3)2 (a and b)), 30.4
(5-C6H2(CMe3)2 (a and b)), 28.7 (3-C6H2(CMe3)2 (a or b), 28.6
(3-C6H2(CMe3)2 (a or b), 8.8 (6H, s, (C6F5)B3Me). 19F NMR
(dichloromethane-d2, 282.2 MHz, 183 K): -135.5 (br s, o-C6F5),
-166.6 (br s, p-C6F5), -169.5 (s, m-C6F5). IR (NaCl plates,
Nujol mull, cm-1): 1783 (vw), 1640 (s), 1614 (s), 1571 (w), 1553
(w), 1510 (vs), 1413 (m), 1366 (s), 1304 (m), 1266 (s), 1238 (s),
1204 (s), 1167 (vs), 1125 (s), 1087 (vs), 1025 (m), 995 (m), 979
1
t
(6-C5H4N), 147.6 (d, JC-F 248 Hz C6F5), 146.1 (5-C6H2 Bu2 (a
t
or b)), 145.7 (5-C6H2 Bu2 (a or b)), 144.5 (4-C5H4N), 136.6 (d
t
1JC-F 249 Hz C6F5), 135.4 (d 1JC-F 232 Hz C6F5), 133.9 (3-C6H2 -
t
Bu2 (a or b)), 133.8 (3-C6H2 Bu2 (a or b)), 125.8 (5-C5H4N), 124.6
(6-C6H2 Bu2 (a and b)), 124.4 (4-C6H2 Bu2 (a and b)), 124.0 (3-
C5H4N), 123.1 (1-C6H2 Bu2 (a or b)), 122.7 (1-C6H2 Bu2 (a or
b)), 76.9 (Ti-Me), 60.5 (NCH2C5H4N), 57.0 (NCH2Ar), 34.4 (3-
t
t
t
t

330 Organometallics, Vol. 24, No. 2, 2005
Boyd et al.
(m), 966 (s), 953 (s), 934 (m), 920 (s), 874 (s), 843 (m), 814 (m),
804 (m), 768 (s), 720 (s), 656 (m), 636 (m), 618 (w), 606 (w),
588 (m), 569 (w). Anal. Found (calcd for C112H112B2F30N4O4-
Ti2‚0.3(CH2Cl2)): C, 58.6 (58.9); H, 5.0 (5.0); N, 2.3 (2.4).
NMR Tube Scale Syntheses of [Ti2(O2tBuNN′)2Me2]‚2-
[B(ArF)4] (22-[B(ArF)4]). To a yellow solution of Ti(O2tBuNN′)-
Me2 (14) (10.0 mg, 0.016 mmol) in dichloromethane-d2 (0.40
mL) was added a solution of [Ph3C][B(ArF)4] (14.8 mg, 0.016
mmol) in dichloromethane-d2 (0.40 mL). The resulting solution
turned immediately orange-red and was transferred to a 5 mm
J. Young NMR tube. The 1H NMR spectrum after 5 min
showed only resonances attributable to [22]2+and MeCPh3,
while the 19F NMR spectrum showed only resonances attribut-
able to [B(ArF)4]-.
toluene (25 mL) was added, and the reactor was placed under
full vacuum for 10 s. The stirring was increased to 750 rpm
and a dynamic pressure of 5 bar of dried ethylene (potassium/
glass wool) applied. After 1 h the polymer was worked up as
for the MAO actication experiment (vide supra).
1-Hexene Polymerization with [Ti2(O2tBuNN)2Me2]‚2-
[MeB(ArF)3] (22-[MeB(ArF)3]). To a solution of Ti(O2tBuNN)-
Me2 (14) (12.4 mg, 0.02 mmol) in 1-hexene (20 mL) in a
preweighed ampule containing a magnetic stirrer bar was
added a solution of B(ArF)3 (10.2 mg, 0.02 mmol) in 1-hexene
(20 mL). Upon mixing a color change from yellow to orange-
red was observed, indicating formation of the species 22-MeB-
(ArF)3. After 6 h the volatiles were removed under reduced
pressure and the sticky residue of polyhexene dried to constant
weight under dynamic vacuum. Yield: 0.057 g (after subtrac-
tion of mass of catalyst and cocatalyst); activity ) 0.50 g
mmol-1 h-1. The polyhexene was characterized by comparison
with literature 1H NMR data in CDCl3.11 Analysis of the
polymer by GPC (RAPRA Technology Ltd) gave Mw ) 60 400,
Mn ) 24 600, Mw/Mn ) 2.5.
NMR Tube Scale Synthesis of [Ti2(O2MeNN′)2Me2]‚2-
[MeB(ArF)3] (23-[MeB(ArF)3]). To a yellow solution of Ti(O2
-
Me
NN′)Me2 (15) (8.8 mg, 0.019 mmol) in dichloromethane-d2 (0.40
mL) was added a solution of B(ArF)3 (10.0 mg, 0.019 mmol) in
dichloromethane-d2 (0.40 mL). The resulting solution turned
immediately orange-red and was transferred to a 5 mm J.
Young NMR tube. The 1H NMR spectrum after 5 min showed
only resonances attributable to [23]2+ and [MeB(ArF)3]-, while
the 19F NMR spectrum showed only resonances attributable
to [MeB(ArF)3]-.
Crystal Structure Determinations of Sc(O2tBuNN′)Cl-
(py)‚C6H6 (2‚C6H6), Sc2(O2MeNN′)2Cl2‚2CH2Cl2 (3‚2CH2Cl2),
Y2(O2tBuNN′)2(µ-Cl)2(py)2‚3(C6H6) (4‚3C6H6), Ti(O2tBuNN′)-
(NMe2)2 (11), Ti(O2tBuNN′)Cl2‚CH2Cl2 (9‚0.5CH2Cl2), Ti-
(O2MeNN′)Cl2‚2.5C6H6 (10‚2.5C6H6), Ti(O2tBuNN′)(NtBu)-
(py)‚2C6H6 (16‚2C6H6), Ti2(O2tBuNN′)2(µ-O)2‚3CH2Cl2 (18‚3-
CH2Cl2), Ti(O2tBuN)(N-2,6-C6H3Me2)(py)‚0.5C6H6 (20‚0.5-
1H NMR (dichloromethane-d2, 500.0 MHz, 293 K): 8.26 (2H,
d, 3J 5.5 Hz 6-C5H4N), 7.68 (2H, app. td, app. 3J 8.0 Hz, 4J 1.5
Hz, 4-C5H4N), 7.15 (2H, at, a 3J 7.0 Hz, 5-C5H4N), 7.07 (2H, s
4-C6H2Me2 (a)), 7.02-6.97 (4H, overlapping m, 3-C5H4N and
6-C6H2Me2 (a)), 6.84 (2H, s, 6-C6H2Me2 (b)), 6.75 (2H, s, 4-C6H2-
Me2 (b)), 4.49-4.68 (6H, overlapping m, NCH2), 4.00 (2H, d,
2J 15.5 Hz, NCH2), 3.68-5.56 (4H, overlapping m, NCH2), 2.34
(12H, overlapping s, 3-C6H2Me2 and Ti-Me), 2.15 (6H, s,
3-C6H2Me2), 2.09 (6H, s, 5-C6H2Me2), 1.95 (6H, s, 5-C6H2Me2)),
0.50 (6H, s, (C6F5)3BMe), The designations (a) and (b) relate
resonances to protons on a specific phenoxy group; however
which group contains the bridging oxygen could not be
determined. 19F NMR (dichloromethane-d2, 282.2 MHz, 293
K): -133.4 (br s, o-C6F5), -165.3 (t, 3J 21.0 Hz, p-C6F5), -167.9
i
C6H6), and Ti(O2tBuN)(N-2,6-C6H3 Pr2)(py) (21). Crystal data
collection and processing parameters are given in Table 11.
Crystals were mounted on a glass fiber using perfluoropoly-
ether oil and cooled rapidly to 150 K in a stream of cold N2
using an Oxford Cryosystems CRYOSTREAM unit. Diffraction
data were measured using an Enraf-Nonius KappaCCD dif-
fractometer. Intensity data were processed using the DENZO-
SMN package.43 The structures were solved using the direct-
methods program SIR92,44 which located all non-hydrogen
atoms. Subsequent full-matrix least-squares refinement was
carried out using the CRYSTALS program suite.45 Coordinates
and anisotropic thermal parameters of all non-hydrogen atoms
were refined. Hydrogen atoms were positioned geometrically
after each cycle of refinement. Weighting schemes were applied
as appropriate. Full listings of atomic coordinates, bond
lengths and angles, and displacement parameters have been
deposited at the Cambridge Crystallographic Data Center. See
Guidelines for Authors, Issue No. 1.
3
(app. t, app. J 19.5 Hz, m-C6F5).
NMR Tube Scale Synthesis of [Ti2(O2MeNN′)2Me2]‚2-
[B(ArF)4] (23-[B(ArF)4]). To a yellow solution of Ti(O2MeNN′)-
Me2 (15) (10.0 mg, 0.022 mmol) in dichloromethane-d2 (0.40
mL) was added a solution of [Ph3C][B(ArF)4] (20.3 mg, 0.022
mmol) in dichloromethane-d2 (0.40 mL). The resulting solution
turned immediately orange-red and was transferred to a 5 mm
J. Young NMR tube. The 1H NMR spectrum after 5 min
showed resonances attributable to [23]2+, while the 19F NMR
spectrum showed only resonances attributable to [B(ArF)4]-.
Ethylene Polymerization with MAO as Activator:
General Procedure. To a sealable metal reactor, containing
a glass insert, was added MAO (20 mL, 10% in toluene w/w:
30 mmol, 1500 equiv) in toluene (200 mL). The solution was
stirred at 250 rpm for 5 min to remove any water or other
impurities. The precatalyst (20 µmol) was dissolved in toluene
(50 mL) and added to the reactor, and the mixture was stirred
for 30 min at 250 rpm. The reaction vessel was placed under
full vacuum for 10 s, the stirring was increased to 750 rpm,
and the reactor was placed under a dynamic pressure of 5 bar
of dried ethylene (potassium/glass wool). After 1 h, the reactor
was vented, and methanol (5 mL) was added to the mixture,
followed by water (50 mL). The mixture was acidified to pH 1
using a solution of 10% HCl in methanol. The polymers were
filtered, washed with water (1000 mL), and dried to constant
weight at room temperature.
Acknowledgment. We thank the EPSRC, Lever-
hulme Trust, and European Commision (Marie Curie
Fellowship) for support of this work. We thank DSM
Research and Albermarle for samples of BArF3, [Ph3C]-
[BArF4], [HNMe2Ph][BArF4], and MAO.
Supporting Information Available: X-ray crystallo-
graphic files in CIF format for the structure determinations
of Sc(O2tBuNN′)Cl(py)‚C6H6 (2‚C6H6), Sc2(O2MeNN′)2Cl2‚2CH2-
Cl2 (3‚2CH2Cl2), Y2(O2tBuNN′)2(µ-Cl)2(py)2‚3(C6H6) (4‚3C6H6),
Ti(O2tBuNN′)(NMe2)2 (11), Ti(O2tBuNN′)Cl2‚CH2Cl2 (9‚0.5CH2-
Cl2), Ti(O2MeNN′)Cl2‚2.5C6H6 (10‚2.5C6H6), Ti(O2tBuNN′)(NtBu)-
(py)‚2C6H6 (16‚2C6H6), Ti2(O2tBuNN′)2(µ-O)2‚3CH2Cl2 (18‚3CH2-
Cl2), Ti(O2tBuN)(N-2,6-C6H3Me2)(py)‚0.5C6H6 (20‚0.5C6H6), and
i
Ti(O2tBuN)(N-2,6-C6H3 Pr2)(py) (21).This material is available
free of charge via the Internet at http://pubs.acs.org.
OM0493661
(43) Otwinowski, Z.; Minor, W. Processing of X-ray Diffraction Data
Collected in Oscillation Mode, Methods in Enzymology; Academic
Press: New York, 1997.
(44) Altomare, A.; Cascarano, G.; Giacovazzo, G.; Guagliardi, A.;
Burla, M. C.; Polidori, G.; Camalli, M. J. Appl. Crystallogr. 1994, 27,
435.
(45) Watkin, D. J.; Prout, C. K.; Carruthers, J. R.; Betteridge, P.
W.; Cooper, R. I. CRYSTALS, issue 11; Chemical Crystallography
Laboratory: Oxford, UK, 2001.
Ethylene Polymerization Using B(ArF)3, [Ph3C][BArF4],
or [HNMe2Ph][BArF4] as Activators: General Procedure.
To a sealable metal reactor, containing a glass insert, was
added AliBu3 (5 mL, 5 mmol, 250 equiv) in toluene (200 mL).
The solution was stirred at 250 rpm for 5 min. The precatalyst
(20 µmol) was dissolved in toluene (25 mL) and added to the
reactor and stirred for 5 min. The cocatalyst (20 µmol) in