Synthesis of titanium, zirconium, and hafnium complexes that contain the [(MesitylN-o-C6H4)2O]2ligand

Article abstract of DOI:10.1021/om0000921

(MesitylNH-o-C₆H₄)₂O (H₂[MesNON]) has been synthesized in ～70% yield, and several [MesNON]^2- complexes of Ti, Zr, and Hf have been prepared, in particular a variety of dialkyl complexes, [MesNON]MR₂ (M = Zr, R = Me, CH₂CMe₃, Ph; M = Hf, R = Me, Et, CH₂CHMe₂, CH₂CMe₃, Ph).

Full text of DOI:10.1021/om0000921

2526
Organometallics 2000, 19, 2526-2531
Syn th esis of Tita n iu m , Zir con iu m , a n d Ha fn iu m
Com p lexes Th a t Con ta in th e [(MesitylN-o-C6H4)2O]2-
Liga n d
Lan-Chang Liang, Richard R. Schrock,* and William M. Davis
Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue,
Cambridge, Massachusetts 02139
Received February 2, 2000
(MesitylNH-o-C6H4)2O (H2[MesNON]) has been synthesized in ∼70% yield, and several
[MesNON]2- complexes of Ti, Zr, and Hf have been prepared, in particular a variety of dialkyl
complexes, [MesNON]MR2 (M ) Zr, R ) Me, CH2CMe3, Ph; M ) Hf, R ) Me, Et, CH2-
CHMe2, CH2CMe3, Ph). [MesNON]ZrMe2 can be activated with [Ph3C][B(C6F5)4] or [PhNMe2H]-
[B(C6F5)4], but the resulting cationic species will only oligomerize 1-hexene. We conclude
that the sterically bulky tert-butyl groups in [(R′N-o-C6H4)2O]2- systems are necessary for
the success of [R′NON]2- Zr catalyst systems for the living polymerization of 1-hexene.
In tr od u ction
or [CyNON]2- ligands gave monomethyl cations that
were capable of reacting with 1-hexene, but 1-hexene
was oligomerized, rather than polymerized. In con-
trast, zirconium dialkyl complexes that contain the
[TMSNON]2- ligand were found to be relatively un-
stable, and any significant chemistry, especially well-
behaved polymerization activity, was thwarted by CH
activation reactions (inter alia). Ligands that contain
a saturated two-carbon backbone and 2,6-disubstituted
We have been exploring the use of diamido donor
ligands for the preparation of early transition metal
complexes, in particular cationic group 4 metal com-
plexes that might serve as catalysts for the polymeri-
zation of R olefins.1-13 The first parent diamine of
a ligand in this general category that we prepared
was (t-BuNHC6H4)2O.1,6,11 The [(t-BuNC6H4)2O]2- ([t-
BuNON]2-) ligand was placed on Ti, Zr, and Hf, and
several dialkyl complexes were prepared. Zirconium
dimethyl complexes activated with [Ph3C][B(C6F5)4]
or [PhNMe2H][B(C6F5)4] were shown to be living cata-
lysts for the polymerization of 1-hexene in chloro-
benzene or bromobenzene at 0 °C.1,6,11 However,
simple variations of the [t-BuNON]2- ligand, namely,
(or 2,4,6-trisubstituted) aryl groups on the amido ni-
2,3
trogen atoms such as [(ArylNCH2CH2)2O]2-
or
[(MesitylNCH2CH2)2NR]2- (R ) H or Me)9 have also
been used successfully to prepare polymerization cata-
lysts, although no example as yet has produced poly(1-
hexene) with the low polydispersity found for that
produced by the [t-BuNON]2- catalysts. Therefore we
became curious as to whether some H2[ArylNON] di-
amine could be prepared, and if so, how complexes that
contain the [ArylNON]2- ligand would compare with
those that contain [t-BuNON]2- or [(ArylNCH2CH2)2O]2-
ligands in terms of the controlled polymerization of
1-hexene. In this contribution we report the synthesis
of (MesitylNHC6H4)2O and zirconium and hafnium
dialkyl complexes that contain the [MesNON]2- ligand.
[(CyclohexylNC6H4)2O]2- 12
,
[(i-PrNC6H4)2O]2- 12
,
or
[(Me3SiNC6H4)2O]2- 13
,
were shown to lead to poor Zr-
based catalysts for the polymerization of 1-hexene by
comparison with the [t-BuNON]2- zirconium system.
Zirconium dialkyl complexes that contain [i-PrNON]2-
(1) Baumann, R.; Davis, W. M.; Schrock, R. R. J . Am. Chem. Soc.
1997, 119, 3830.
(2) Schrock, R. R.; Schattenmann, F.; Aizenberg, M.; Davis, W. M.
Chem. Commun. 1998, 199.
(3) Aizenberg, M.; Turculet, L.; Davis, W. M.; Schattenmann, F.;
Schrock, R. R. Organometallics 1998, 17, 4795.
(4) Schattenmann, F.; Schrock, R. R.; Davis, W. M. Organometallics
1998, 17, 989.
(5) Schrock, R. R.; Lee, J .; Liang, L.-C.; Davis, W. M. Inorg. Chim.
Acta 1998, 270, 353.
(6) Baumann, R.; Schrock, R. R. J . Organomet. Chem. 1998, 557,
69.
(7) Schrock, R. R.; Seidel, S. W.; Schrodi, Y.; Davis, W. M. Organo-
metallics 1999, 118, 428.
(8) Graf, D. D.; Schrock, R. R.; Davis, W. M.; Stumpf, R. Organo-
metallics 1999, 18, 843.
(9) Liang, L.-C.; Schrock, R. R.; Davis, W. M.; McConville, D. H. J .
Am. Chem. Soc. 1999, 120, 5797.
(10) Flores, M. A.; Manzoni, M.; Baumann, R.; Davis, W. M.;
Schrock, R. R. Organometallics 1999, 18, 3220.
(11) Schrock, R. R.; Baumann, R.; Reid, S. M.; Goodman, J . T.;
Stumpf, R.; Davis, W. M. Organometallics 1999, 18, 3649.
(12) Baumann, R.; Stumpf, R.; Davis, W. M.; Liang, L.-C.; Schrock,
R. J . Am. Chem. Soc. 1999, 121, 7822.
Resu lts
H2[MesNON] can be synthesized in ∼70% yield by the
palladium-catalyzed C-N bond-forming reaction be-
14
tween O(o-C6H4NH2)2 and 2 equiv of mesityl bromide
under conditions similar to those reported by Buchwald
and co-workers.15,16 The reaction requires more vigorous
conditions (6 days in toluene at 95 °C) than the reaction
between mesityl bromide and diethylenetriamine, for
example.9 The product was isolated in 66% yield (∼7 g)
after purification by passage through alumina.
(14) Randall, J . J .; Lewis, C. E.; Slagan, P. M. J . Org. Chem. 1962,
27 (7), 4098.
(15) Wolfe, J . P.; Wagaw, S.; Buchwald, S. L. J . Am. Chem. Soc.
1996, 118, 7215.
(13) Schrock, R. R.; Liang, L.-C.; Baumann, R.; Davis, W. M. J .
Organomet. Chem. 1999, 591, 163.
(16) Wolfe, J . P.; Wagaw, S.; Marcoux, J .-F.; Buchwald, S. L. Acc.
Chem. Res. 1998, 31, 805.
10.1021/om0000921 CCC: $19.00 © 2000 American Chemical Society
Publication on Web 05/24/2000

Synthesis of Ti, Zr, and Hf Complexes
Organometallics, Vol. 19, No. 13, 2000 2527
Ta ble 1. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
Sch em e 1
a
for [MesNON]Hf(CH2CMe3)2
empirical formula
fw
C40H52HfN2O
755.33
cryst syst
space group
a (Å)
b (Å)
c (Å)
monoclinic
P21/c
9.82720(10)
20.25430(10)
18.5991(3)
90.0180(10)
100.7380(10)
90.0000(10)
3637.20(7)
4
R (deg)
â (deg)
γ (deg)
volume (Å3)
Z
density (calcd; Mg/m3)
1.379
2.899
abs coeff (mm-1
)
F(000)
1544
crystal size (mm)
θ range for data collection
limiting indices
0.2 × 0.2 × 0.2
1.50-23.26
-9 e h e 10
-18 e k e 21
-20 e l e 10
11 381
A suitable entry into titanium chemistry employs
TiCl2(NMe2)2. Addition of 2 equiv of butyllithium to H2-
[MesNON] in diethyl ether followed by addition of TiCl2-
(NMe2)2 led to dark red [MesNON]Ti(NMe2)2 in good
yield (Scheme 1). Proton NMR data for [MesNON]Ti-
(NMe2)2 are consistent with a structure that has two
planes of symmetry, and the methyl groups in the
dimethylamide ligands are equivalent, as is usually the
case in dimethylamido complexes in general. Upon
heating [MesNON]Ti(NMe2)2 with excess Me3SiCl in
toluene at 110 °C for 6 days, red, crystalline [MesNON]-
TiCl(NMe2) was formed essentially quantitatively. Heat-
ing such mixtures to higher temperatures did not
appear to yield [MesNON]TiCl2 cleanly. Attempts to
synthesize [MesNON]TiCl2 by treating TiCl2(NMe2)2
with H2[MesNON] gave a 1:1 mixture of H2[MesNON]
and [MesNON]TiCl(NMe2), according to 1H NMR spec-
tra, while attempts to react [MesNON]Ti(NMe2)2 with
2 equiv of ethereal HCl led to formation of substantial
amounts of H2[MesNON]. The 1H NMR spectrum of
[MesNON]TiCl(NMe2) exhibits three singlet resonances
at 2.37, 2.15, and 1.98 ppm for the mesityl methyl
groups and one singlet resonance at 2.58 ppm for the
dimethylamide ligand. It is likely that [MesNON]TiCl-
(NMe2) contains only one mirror plane, which bisects
the [MesNON]2- ligand, and that the mesityl rings in
[MesNON]2- do not rotate readily on the NMR time
scale, thereby giving rise to inequivalent ortho methyl
groups.
no. of reflns collected
no. of ind reflns
4935
abs corr
none
4931/0/417
1.276
R1 ) 0.0477, wR2 ) 0.0912
R1 ) 0.0570, wR2 ) 0.0970
0.00069(11)
0.588 and -1.046
no. of data/restraints/params
goodness-of-fit on F2
final R indices [I>2σ(I)]b
R indices (all data)b
extinction coeff
largest diff peak and hole (e Å-3
)
a
Data were collected at 181(2) K using Mo KR radiation
(0.71073 Å) and refined by full-matrix least-squares on F2. R1
b
) ∑||Fo| - |Fc||/∑|Fo|; wR2 ) [(∑w(|Fo| - |Fc|)2/∑wFo2)]1/2
.
[MesNON]ZrMe2 reveal only one sharp singlet reso-
nance for the two methyl ligands at temperatures
between -80 and 90 °C and one singlet resonance for
ortho mesityl methyl groups. The 13C NMR spectra of
[MesNON]ZrPh2 and [MesNON]HfPh2 suggest that the
two phenyl ligands are equivalent on the NMR time
scale. All other proton and carbon NMR spectra at room
temperature were consistent with the presence of a
mirror plane on the NMR time scale. The stability of
the ethyl and isobutyl complexes toward â abstraction
is not surprising, as there are now several examples of
diamido donor dialkyl complexes of Zr or (especially) Hf
in this category.11,12
A single crystal of [MesNON]Hf(CH2CMe3)2 was
grown from a saturated solution of diethyl ether,
benzene, and pentane at -30 °C. An X-ray study (Table
1) shows [MesNON]Hf(CH2CMe3)2 to have a structure
that is close to a square pyramid with C(1) in the apical
position (Figure 1; Table 2), which is approximately
halfway between the two “ideal” structures for com-
plexes of this type, the fac and mer forms as shown in
eq 1. The best measure of the core structure is the angle
The reaction between H2[MesNON] and Zr(NMe2)4 in
diethyl ether at room temperature gave colorless [Mes-
NON]Zr(NMe2)2 in quantitative yield. Subsequent reac-
tion of [MesNON]Zr(NMe2)2 with an excess (∼3 to 4
equiv) of Me3SiCl in toluene at room temperature gave
[MesNON]ZrCl2 in high yield. Analogous hafnium com-
plexes, [MesNON]Hf(NMe2)2 and [MesNON]HfCl2, were
synthesized similarly in two steps in ∼70% overall yield
(Scheme 1).
Alkylation of [MesNON]MCl2 (M ) Zr of Hf) com-
plexes with magnesium or lithium reagents in diethyl
ether or toluene gave the corresponding dialkyl or
diphenyl complexes, [MesNON]MR2 (M ) Zr, R ) Me,
CH2CMe3, Ph; M ) Hf, R ) Me, Et, CH2CHMe2, CH2-
CMe3, Ph) in 79-95% yields (Scheme 1). Neopentyl-
lithium was employed to prepare neopentyl derivatives;
in all other cases Grignard reagents were employed.
Variable-temperature 1H NMR spectra (500 MHz) of
between the O-Hf-N(1) and O-Hf-N(2) planes (145.6°);
other angles at the metal are listed in Table 2. For
comparison, the corresponding angle in [t-BuNON]-
ZrMe2, which has the fac structure, is 124°, while in
[(2,6-i-Pr2C6H3NCH2CH2)2O]HfEt2, the molecule that

2528 Organometallics, Vol. 19, No. 13, 2000
Liang et al.
F igu r e 1. Labeled ORTEP drawing of [MesNON]Hf(CH2-
CMe3)2.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) in [MesNON]Hf(CH2CMe3)2
Bond Lengths
F igu r e 2. Proton NMR spectra (500 MHz) of the product
of the reactions between 1-hexene (60 equiv) and [Ph3C]-
[B(C6F5)4]-activated [CyNON]ZrMe2 (top) or [MesNON]-
ZrMe2 (bottom) in C6D5Br at 0 °C.
Hf-N(1)
Hf-N(2)
Hf-O
2.114(6)
2.093(6)
2.332(5)
Hf-C(1)
Hf-C(6)
2.210(7)
2.225(7)
Bond Angles
C(1)-Hf-C(6)
C(1)-Hf-N(1)
C(1)-Hf-N(2)
C(1)-Hf-O
C(6)-Hf-N(1)
C(6)-Hf-N(2)
C(6)-Hf-O
107.4(3)
110.4(3)
107.0(3)
97.5(2)
101.2(3)
101.0(3)
155.1(3)
N(1)-Hf-N(2)
127.7(2)
69.5(2)
70.5(2)
122.0(5)
125.0(4)
133.0(5)
132.5(6)
1-hexene readily. For instance, addition of 60 equiv of
1-hexene to [Ph3C][B(C6F5)4] activated [MesNON]ZrMe2
in C6D5Br at 0 °C leads to a complete consumption of
1-hexene in 10 min. However, relatively intense olefinic
resonances are observed near 4.9 and 5.5 ppm that can
be ascribed to olefinic resonances in â elimination
products (Figure 2) on the basis of studies involving
propylene end groups in relatively inefficient propylene
polymerization catalysts.17,18 We tentatively ascribe the
resonances near 4.9 ppm to 1,1-disubstituted olefins
that result from â elimination in a 1,2 insertion product
and resonances near 5.5 ppm to internal olefins that
result from â elimination in a 2,1 insertion product. The
ratio of the olefinic proton resonances suggests that
approximately 80% arises from â elimination in a 2,1
insertion product. On the basis of the relative intensity
of the aliphatic resonances in the region between 1 and
2 ppm, only ∼10 equiv on the average of 1-hexene are
present in an oligomeric chain. It should be noted that
virtually identical behavior is observed for [CyNON]-
ZrMe2 activated by [Ph3C][B(C6F5)4] (Figure 2). Similar
results are observed for [MesNON]ZrMe2 activated by
[HNMe2Ph][B(C6F5)4], although the rate of oligomer-
ization is noticeably slower than when [Ph3C][B(C6F5)4]
is employed as the activating agent. Although more
N(1)-Hf-O
O-Hf-N(2)
Hf-N(1)-C(11)
Hf-N(2)-C(41)
Hf-C(1)-C(2)
Hf-C(6)-C(7)
Dihedral Angles
145.5
179.0
N(2)/O/Hf/N(1)
C(1)/O/Hf/C(6)
Hf/N(1)/C(11)/C(16)
Hf/N(2)/C(41)/C(42)
90.0
89.5
structurally most resembles [MesNON]Hf(CH2CMe3)2,
it is 160°.3,8 In a mer structure, e.g., [i-PrNON]Zr(CH2-
CHMe2)2,12 the angle between the planes is 180°. The
neopentyl ligands in [MesNON]Hf(CH2CMe3)2 are turned
so that C(7) points away from N(1) and N(2), while C(2)
points away from the tert-butyl group containing C(7).
In this sense the structure is similar to that of [i-PrNON]-
Zr(CH2CHMe2)2.12 The two amido nitrogens are sp2-
hybridized, as evidenced by the sum of the angles
around them (N(1) ) 359.6° and N(2) ) 359.8°). The
mesityl rings lie perpendicular to the plane of the
o-phenylene backbone with Hf-N(1)-C(11)-C(16) and
Hf-N(2)-C(41)-C(42) dihedral angles of 90.7° and
89.5°, respectively. The Hf-O, Hf-Namide, and Hf-CR
bond distances in [(MesNON]Hf(CH2CMe3)2 are all
within ∼0.02 Å of those in [(2,6-i-Pr2C6H3NCH2CH2)2O]-
HfEt2.3
(17) Resconi, L.; Piemontesi, F.; Camurati, I.; Balboni, D.; Sironi,
A.; Moret, M.; Rychlicki, H.; Zeigler, R. Organometallics 1996, 15, 5046.
(18) Resconi, L.; Piemontesi, F.; Camurati, I.; Sudmeijer, O.; Nifant’ev,
I. E.; Ivchenko, P. V.; J uz’mina, L. G. J . Am. Chem. Soc. 1998, 120,
2308.
[MesNON]ZrMe2 reacts with [Ph3C][B(C6F5)4] or
[HNMe2Ph][B(C6F5)4] in C6D5Br at 0 °C to yield what
we presume are cationic species. These species consume

Synthesis of Ti, Zr, and Hf Complexes
Organometallics, Vol. 19, No. 13, 2000 2529
sparged with nitrogen and passed through two columns of
activated alumina. Pentane was sparged with nitrogen, then
passed through one column of activated alumina and then
through another of activated Q5.20 All NMR solvents were
sparged with nitrogen and dried over activated 4 Å molecular
sieves for several days prior to use.
detailed studies will be required in order to positively
identify these proposed olefinic products of â elimina-
tion, it is clear that activated [CyNON]ZrMe2 and
[MesNON]ZrMe2 systems behave similarly and that
neither is an efficient 1-hexene polymerization catalyst.
Chemical shifts (δ) are listed as parts per million and
coupling constants in hertz. (Routine coupling constants are
not listed.) 1H NMR spectra are referenced using the residual
solvent peak at δ 7.16 for C6D6, δ 7.29 for C6D5Br (the most
upfield resonance), δ 7.27 for CDCl3, and δ 2.09 for toluene-d8
(the most downfield resonance). 13C NMR spectra are refer-
enced using the residual solvent peak at δ 128.39 for C6D6, δ
77.23 for CDCl3, and δ 137.86 for toluene-d8 (the most
downfield resonance). All NMR spectra were recorded at room
temperature unless noted otherwise. Elemental analyses were
performed by H. Kolbe Mikroanalytisches Laboratorium, Mu¨l-
heim an der Ruhr, Germany.
Discu ssion
Steric crowding in [R′NON]MR2 complexes has been
employed in a qualitative sense as some measure of the
extent of steric crowding that will develop in {[R′NON]-
MR}+ species, especially when R is the growing chain
that results from polymerization of 1-hexene. [t-BuNON]-
MR2 species are the only [R′NON]2- species that have
a fac structure, and the [t-BuNON]2- system is the only
one that yields a catalyst for the living polymerization
of 1-hexene at 0 °C.6,11 Steric crowding in pseudotetra-
hedral {[R′NON]MR}+ is proposed to encourage the
insertion of 1-hexene into the M-R bond in a 1,2
manner and to limit the extent to which â hydride
elimination can take place from a 1,2 insertion product
so formed. Too little steric crowding, i.e., a more “open”
and distorted tetrahedral structure, is believed to allow
2,1 insertion to take place and therefore to lead to more
facile â elimination. “Smaller” R′ groups (i-Pr, cyclo-
hexyl) apparently simply are not bulky enough to lead
to formation of crowded pseudotetrahedral {[R′NON]-
MR}+ species. It is now clear that mesityl is in the same
class as isopropyl and cyclohexyl in [R′NON]2- systems
and that any electronic difference between an aryl-
substituted [R′NON]2- system and an alkyl-substituted
[R′NON]2- system is overshadowed by steric consider-
ations. Only when R′ ) t-Bu can a sufficiently crowded
pseudotetrahedral structure for {[R′NON]MR}+ be main-
tained.
The premise that a pseudotetrahedral structure alone
is responsible for limiting 2,1 “misinsertions” and facile
â elimination is being tested in two ways. One approach
is to link the two arms in a [(ArylNCH2CH2)2O]2- ligand
system through the two carbon atoms R to the oxygen
donor.10 The oxygen donor now cannot invert and
pseudotetrahedral {[R′NON]MR}+ structures are more
naturally formed. A second method is to employ a donor
that cannot invert when bound to the metal, in particu-
lar an amine nitrogen donor.9 (Diamido donor ligands
that contain a central sulfur donor clearly do not invert
as readily as those that contain an oxygen donor, but
so far controlled polymerization activity with compounds
that contain sulfur donor ligands has been disappoint-
ing.8) A third approach in which the amido substituents
are linked to one another is synthetically relatively
difficult and in at least one case has been shown to fail.13
Complexes in which the ligand contains a nitrogen
donor are currently showing the most promise, and
research therefore is being aimed in that direction.9,19
Starting materials (O(o-C6H4NH2)2,14 TiCl2(NMe2)2,21 Zr-
(NMe2)4,22 Hf(NMe2)4,23 NpLi,24 and NpMgCl25 were prepared
as reported in the literature. PhMe2CCH2MgCl was prepared
in a manner similar to the preparation of NpMgCl. Zinc dust
(97.5%) was activated with 5% aqueous HCl prior to use.26
HfCl4 (99%, <0.2% Zr) was purchased from Cerac; other metal
halides were purchased from Strem. [HNMe2Ph][B(C6F5)4] and
[Ph3C][B(C6F5)4] were gifts from the Exxon Chemical Corpora-
tion. All other chemicals were purchased from commercial
suppliers. Pyridine and lutidines were sparged with nitrogen
and dried over activated 4 Å molecular sieves prior to use.
Mesityl bromide was sparged with nitrogen prior to use.
1-Hexene was refluxed over sodium for 4 days and distilled.
All other chemicals were used as received.
H2[MesNON]. A 250 mL Schlenk flask was charged with
O(o-C6H4NH2)2 (5.00 g, 25.0 mmol), mesityl bromide (9.94 g,
49.9 mmol), tris(dibenzylideneacetone)dipalladium(0) (0.114 g,
0.125 mmol), rac-BINAP (0.233 g, 0.375 mmol), NaO-t-Bu (6.72
g, 69.9 mmol), and toluene (100 mL). The reaction mixture
was stirred with a magnetic stirrer and stir bar at 95 °C for 6
days. All volatile components were removed in vacuo at ∼40
°C, and the resulting dark brown solid residue was dissolved
in a mixture of diethyl ether (400 mL) and water (300 mL).
The two layers were separated, and the diethyl ether layer
was washed with water (3 × 300 mL) and saturated aqueous
NaCl solution (300 mL) and dried over MgSO4. The MgSO4
was removed by filtration, and the filtrate was concentrated
on a rotary evaporator until the volume was ∼10 mL. The
concentrated solution was loaded onto an alumina column (2.5
cm inner diameter × 27 cm height), and the product was eluted
with diethyl ether. The first 500 mL of eluent was collected,
and the solvent was removed in vacuo to give a pale yellow
solid; yield 7.19 g (66%): 1H NMR (C6D6) δ 7.04 (d, 2, Aryl),
6.83 (t, 2, Aryl), 6.80 (s, 4, Aryl), 6.62 (t, 2, Aryl), 6.41 (d, 2,
Aryl), 5.69 (s, 2, NH), 2.17 (s, 6, Mep), 2.09 (s, 12, Meo); 1H
NMR (CDCl3) δ 6.98 (d, 2, Aryl), 6.95 (s, 4, Aryl), 6.89 (t, 2,
Aryl), 6.68 (t, 2, Aryl), 6.27 (d, 2, Aryl), 5.71 (s, 2, NH), 2.32
(s, 6, Mep), 2.16 (s, 12, Meo); 13C NMR (C6D6) δ 144.72 (CAr),
139.05 (CAr), 136.79 (CAr), 136.03 (CAr), 135.94 (CAr), 130.01
(CArH), 125.28 (CArH), 119.25 (CArH), 118.36 (CArH), 112.99
(CArH), 21.42 (Mep), 18.58 (Meo); HRMS (EI, 70 eV) calcd for
C
30H32N2O 436.25146, found 436.25091.
(20) Pangborn, A. B.; Giardello, M. A.; Grubbs, R. H.; Rosen, R. K.;
Timmers, F. J . Organometallics 1996, 15, 1518.
(21) Benzing, E.; Kornicker, W. Chem. Ber. 1961, 94, 2263.
(22) Diamond, G. M.; Rodewald, S.; J ordan, R. F. Organometallics
1995, 14, 5.
(23) Diamond, G. M.; J ordan, R. F.; Petersen, J . L. Organometallics
1996, 15, 4030.
(24) Schrock, R. R.; Fellmann, J . D. J . Am. Chem. Soc. 1978, 100,
3359.
(25) Schrock, R. R.; Sancho, J .; Pederson, S. F. Inorganic Syntheses;
Kaesz, H. D., Ed.; J ohn Wiley & Sons: New York; Vol. 26, pp 44-51.
(26) Micovic, I. V.; Ivanovic, M. D.; Piatak, D. M.; Bojic, V. D.
Synthesis 1991, 1043.
Exp er im en ta l Section
Gen er a l P r oced u r es. Unless otherwise specified, all ex-
periments were performed under dinitrogen in a Vacuum
Atmospheres glovebox or by using standard Schlenk tech-
niques. All solvents were reagent grade or better. Toluene was
distilled from sodium/benzophenone ketyl. Diethyl ether was
(19) Mehrkhodavandi, P.; Bonitatebus, P. J .; Schrock, R. R., submit-
ted.

2530 Organometallics, Vol. 19, No. 13, 2000
Liang et al.
[MesNON]Ti(NMe2)2. Butyllithium (0.92 mL, 2.5 M in
hexane, 2.3 mmol) was added to a diethyl ether solution (12
mL) of H2[MesNON] (500 mg, 1.15 mmol) at -30 °C. The
solution was stirred at room temperature for 1.5 h and cooled
to -30 °C. Solid TiCl2(NMe2)2 (237 mg, 1.15 mmol) was added.
The reaction mixture was stirred at room temperature over-
night (∼14 h). Insoluble materials were removed by filtration
through Celite and washed with diethyl ether (5 mL). The
filtrate was concentrated in vacuo until the volume was ∼2
mL. Pentane (∼1 mL) was layered on top, and the mixture
was cooled to -30 °C to give a dark red needlelike crystalline
solid. The supernatant was decanted, and the solid was dried
in vacuo; yield 475 mg (73%): 1H NMR (C6D6) δ 7.63 (d, 2,
Aryl), 6.87 (s, 4, Aryl), 6.86 (t, 2, Aryl), 6.60 (t, 2, Aryl), 6.22
(d, 2, Aryl), 2.77 (s, 12, TiNMe2), 2.20 (s, 6, Mep), 2.16 (s, 12,
Meo); 13C NMR (C6D6) δ 148.61 (CAr), 147.28 (CAr), 147.14 (CAr),
134.13 (CAr), 133.63 (CAr), 129.68 (CArH), 126.08 (CArH), 116.62
(CArH), 116.24 (CArH, 113.68 (CArH), 45.56 (NMe2), 21.31 (Mep),
19.67 (Meo). Anal. Calcd for C34H42N4OTi: C, 71.57; H, 7.42;
N; 9.82. Found: C, 71.69; H, 7.48; N, 9.71.
(s, 12, Meo), 2.10 (s, 6, Mep); 13C NMR (C6D6) δ 148.29 (CAr),
145.91 (CAr), 139.50 (CAr), 137.64 (CAr), 135.68 (CAr), 130.91
(CArH), 127.22 (CArH), 119.50 (CArH), 116.69 (CArH), 114.12
(CArH), 21.37 (Mep), 19.10 (Meo). Anal. Calcd for C30H30Cl2N2-
OZr(ether)0.67: C, 60.73; H, 5.72; N, 4.33. Found: C, 60.85; H,
5.86; N, 4.27.
[MesNON]Zr Me2. MeMgI (0.10 mL, 3.0 M in diethyl ether,
0.30 mmol) was added to a diethyl ether solution (4 mL) of
[MesNON]ZrCl2 (98 mg, 0.15 mmol) at -30 °C. The reaction
mixture was stirred at room temperature for 2.5 h, and the
solvent was removed in vacuo. The solid residue was extracted
with pentane (10 mL). Insoluble materials were removed by
filtration through Celite. The colorless filtrate was concen-
trated in vacuo until the volume was ∼2 mL and was cooled
to -30 °C to give colorless crystals. The supernatant was
decanted, and the crystals were dried in vacuo; yield 71 mg
(85%): 1H NMR (C6D6) δ 7.53 (d, 2, Aryl), 6.92 (s, 4, Aryl),
6.82 (t, 2, Aryl), 6.52 (t, 2, Aryl), 6.20 (d, 2, Aryl), 2.27 (s, 12,
1
Meo), 2.16 (s, 6, Mep), 0.58 (s, 6, ZrMe); H NMR (toluene-d8)
δ 7.47 (d, 2, Aryl), 6.87 (s, 4, Aryl), 6.77 (t, 2, Aryl), 6.49 (t, 2,
Aryl), 6.12 (d, 2, Aryl), 2.23 (s, 12, Meo), 2.14 (s, 6, Mep), 0.49
[MesNON]TiCl(NMe2). A toluene solution (5 mL) of [Mes-
NON]Ti(NMe2)2 (104 mg, 0.182 mmol) and Me3SiCl (0.07 mL,
0.552 mmol) was heated to 105 °C for 6 days in a Teflon-sealed
Schlenk tube. All volatile materials were removed in vacuo at
∼40 °C to give a deep red solid, which is pure [MesNON]TiCl-
(NMe2), according to its 1H NMR spectrum. The solid was
recrystallized from a concentrated diethyl ether solution at
-30 °C to give blood red crystals; yield 102 mg (100%): 1H
NMR (C6D6) δ 7.53 (d, 2, Aryl), 6.83 (s, 2, Aryl), 6.79 (t, 2, Aryl),
6.76 (s, 2, Aryl), 6.56 (t, 2, Aryl), 6.02 (d, 2, Aryl), 2.58 (s, 6,
1
(s, 6, ZrMe); H NMR (toluene-d8, -80 °C) δ 7.33 (d, 2, Aryl),
6.73 (s, 4, Aryl), 6.70 (t, 2, Aryl), 6.38 (t, 2, Aryl), 6.11 (d, 2,
1
Aryl), 2.20 (s, 12, Meo), 2.00 (s, 6, Mep), 0.58 (s, 6, ZrMe); H
NMR (toluene-d8, 90 °C) δ 7.53 (d, 2, Aryl), 6.91 (s, 4, Aryl),
6.79 (t, 2, Aryl), 6.53 (t, 2, Aryl), 6.13 (d, 2, Aryl), 2.25 (s, 12,
Meo), 2.17 (s, 6, Mep), 0.45 (s, 6, ZrMe); 13C NMR (C6D6) δ
147.03 (CAr), 146.19 (CAr), 138.43 (CAr), 136.87 (CAr), 136.65
(CAr), 130.75 (CArH), 126.43 (CArH), 117.31 (CArH), 115.18
(CArH), 113.80 (CArH), 49.85 (ZrMe), 21.42 (Mep), 19.00 (Meo).
Anal. Calcd for C32H36N2OZr: C, 69.14; H, 6.53; N; 5.04.
Found: C, 69.26; H, 6.37; N, 5.11.
[MesNON]Zr (CH2CMe3)2. A diethyl ether solution (2 mL)
of LiCH2CMe3 (28 mg, 0.36 mmol) at -30 °C was added to a
diethyl ether suspension (4 mL) of [MesNON]ZrCl2 (116 mg,
0.179 mmol) at -30 °C. The reaction mixture was stirred at
room temperature for 1 h, and the solvent was removed in
vacuo. The solid residue was extracted with pentane (10 mL),
and insoluble materials were removed by filtration through
Celite. The solvent was removed from the filtrate in vacuo to
give a pale yellow solid; yield 100 mg (83%): 1H NMR (C6D6)
δ 7.60 (d, 2, Aryl), 6.91 (s, 4, Aryl), 6.81 (t, 2, Aryl), 6.55 (t, 2,
Aryl), 6.23 (d, 2, Aryl), 2.37 (s, 12, Meo), 2.17 (s, 6, Mep), 1.29
(s, 4, CH2CMe3), 0.90 (s, 18, CH2CMe3); 13C NMR (C6D6) δ
147.24 (CAr), 147.11 (CAr), 141.90 (CAr), 136.37 (CAr), 135.99
(CAr), 130.80 (CArH), 126.47 (CArH), 117.58 (CArH), 116.30
(CArH), 114.43 (CArH), 96.57 (ZrCH2CMe3), 36.99 (ZrCH2CMe3),
34.52 (ZrCH2CMe3), 21.32 (Mep), 19.64 (Meo).
[MesNON]Zr P h 2. PhMgBr (0.10 mL, 3.0 M in diethyl ether,
0.30 mmol) was added to a diethyl ether suspension (4 mL) of
[MesNON]ZrCl2(ether)0.67 (97.0 mg, 0.150 mmol) at -30 °C.
The color of the suspension changed immediately from green
to yellow. The reaction mixture was stirred at room temper-
ature for 1.5 h, and 1,4-dioxane (5 drops) was added. Insoluble
materials were removed by filtration through Celite, and the
filtrate was concentrated in vacuo until the volume was ∼1
mL. The concentrated solution was cooled to -30 °C overnight
to give a yellow crystalline solid. The supernatant was
decanted, and the product was dried in vacuo; yield 94 mg
(92%): 1H NMR (C6D6) δ 7.62 (d, 2, Aryl), 7.52 (m, 4, Aryl),
7.00 (m, 6, Aryl), 6.80 (t, 2, Aryl), 6.75 (s, 4, Aryl), 6.61 (t, 2,
Aryl), 6.19 (d, 2, Aryl), 2.15 (s, 6, Mep), 2.05 (s, 12, Meo); 13C
NMR (C6D6) δ 191.70 (ZrCipso), 147.29 (CAr), 147.08 (CAr),
139.72 (CAr), 136.76 (CAr), 136.67 (CAr), 133.94 (CArH), 130.59
(CArH), 129.68 (CArH), 127.37 (CArH), 126.62 (CArH), 118.15
(CArH), 116.17 (CArH), 114.04 (CArH), 21.31 (Mep), 19.17 (Meo).
Anal. Calcd for C42H40N2OZr: C, 74.18; H, 5.93; N; 4.12.
Found: C, 74.08; H, 6.05; N, 4.18.
TiNMe2), 2.37 (s, 6, Mep), 2.15 (s, 6, Meo), 1.98 (s, 6, Meo); 13
C
NMR (C6D6) δ 149.15 (CAr), 148.17 (CAr), 146.67 (CAr), 135.04
(CAr), 134.70 (CAr), 131.98 (CAr), 130.10 (CArH), 129.66 (CArH),
126.23 (CArH), 118.37 (CArH), 117.09 (CArH), 112.30 (CArH),
46.09 (NMe2), 21.24 (Mep), 19.54 (Meo), 18.81 (Meo). Anal. Calcd
for C32H36ClN3OTi: C, 68.39; H, 6.46; N; 7.48. Found: C, 68.48;
H, 6.35; N, 7.39.
[MesNON]Zr (NMe2)2. Diethyl ether (10 mL) was added to
a solid mixture of H2[MesNON] (1.03 g, 2.36 mmol) and Zr-
(NMe2)4 (0.632 g, 2.36 mmol) at room temperature. The
solution was stirred at room temperature overnight (∼13 h).
All volatile components were removed in vacuo to give a pale
yellow solid, which was pure [MesNON]Zr(NMe2)2, according
1
to its H NMR spectrum. Colorless crystals were obtained from
a concentrated diethyl ether solution at -30 °C. The crystals
were collected by filtration and dried in vacuo; yield 1.43 g
(98%): 1H NMR (C6D6) δ 7.60 (d, 2, Aryl), 6.89 (s, 4, Aryl),
6.86 (t, 2, Aryl), 6.56 (t, 2, Aryl), 6.25 (d, 2, Aryl), 2.57 (s, 12,
Meo), 2.20 (s, 18, containing 6H from Mep and 12H from
1
ZrNMe2); H NMR (toluene-d8) δ 7.56 (d, 2, Aryl), 6.85 (s, 4,
Aryl), 6.79 (t, 2, Aryl), 6.52 (t, 2, Aryl), 6.17 (d, 2, Aryl), 2.54
(s, 12, Meo), 2.17 (s, 6, Mep), 2.16 (s, 12, ZrNMe2); 13C NMR
(C6D6) δ 147.56 (CAr), 146.57 (CAr), 143.40 (CAr), 135.17 (CAr),
134.08 (CAr), 129.97 (CArH), 126.60 (CArH), 116.89 (CArH),
116.12 (CArH), 114.35 (CArH), 41.64 (ZrNMe2), 21.36 (Mep),
18.93 (Meo). Anal. Calcd for C34H42N4OZr: C, 66.52; H, 6.90;
N, 9.13. Found: C, 66.64; H, 6.82; N, 9.05.
[MesNON]Zr Cl2. Neat Me3SiCl (0.640 mL, 5.07) was added
to a toluene solution (20 mL) of [MesNON]Zr(NMe2)2 (1.04 g,
1.69 mmol) at room temperature. The reaction mixture was
stirred at room temperature for 24 h. All volatile components
were removed in vacuo at ∼40 °C to give a viscous brown oil.
Diethyl ether was added dropwise to the oil to initiate
crystallization. A crop of yellow crystalline solid (696 mg) was
obtained from ∼5 mL of diethyl ether solution at room
temperature. A second crop (225 mg) was obtained by cooling
the mother liquor to -30 °C; total yield 921 mg (91%). Diethyl
ether (∼0.67 equiv per zirconium) was usually found in the
1
crystalline product, according to H NMR spectra: 1H NMR
[MesNON]Hf(NMe2)2 a n d [MesNON]HfCl2. Diethyl ether
(20 mL) was added to a solid mixture of H2[MesNON] (1.30 g,
2.98 mmol) and Hf(NMe2)4 (1.06 g, 2.98 mmol) at room
(C6D6; ether resonaces excluded) δ 7.34 (d, 2, Aryl), 6.81 (s, 4,
Aryl), 6.75 (t, 2, Aryl), 6.52 (t, 2, Aryl), 6.06 (d, 2, Aryl), 2.30

Synthesis of Ti, Zr, and Hf Complexes
Organometallics, Vol. 19, No. 13, 2000 2531
temperature. The reaction was monitored by 1H NMR spec-
troscopy, which showed that [MesNON]Hf(NMe2)2 had been
formed quantitatively after 6 h. All volatile components were
removed in vacuo to give [MesNON]Hf(NMe2)2 as an off-white
solid; yield 2.09 g (100%): 1H NMR (C6D6) δ 7.57 (d, 2, Aryl),
6.90 (s, 4, Aryl), 6.85 (t, 2, Aryl), 6.55 (t, 2, Aryl), 6.26 (d, 2,
Aryl), 2.62 (s, 12, HfNMe2), 2.22 (s, 12, Meo), 2.19 (s, 6, Mep).
Neat Me3SiCl (1.40 mL, 11.93 mmol) was added to a toluene
solution (5 mL) of [MesNON]Hf(NMe2)2 at room temperature.
After 22 h all volatile components were removed in vacuo at
∼45 °C, and the off-white solid was washed with pentane (∼20
mL) and dried in vacuo; yield 1.45 g (71%): 1H NMR (C6D6) δ
7.28 (d, 2, Aryl), 6.82 (s, 4, Aryl), 6.77 (t, 2, Aryl), 6.47 (t, 2,
Aryl), 6.11 (d, 2, Aryl), 2.13 (s, 12, Meo), 2.11 (s, 6, Mep); 13C
NMR (C6D6) δ 148.05 (CAr), 145.98 (CAr), 140.41 (CAr), 137.06
(CAr), 135.68 (CAr), 130.82 (CArH), 127.61 (CArH), 119.09 (CArH),
117.05 (CArH), 115.14 (CArH), 21.32 (Mep), 19.01 (Meo). Anal.
Calcd for C30H30Cl2HfN2O: C, 52.68; H, 4.42; N; 4.10. Found:
C, 52.83; H, 4.50; N, 4.29.
[MesNON]HfMe2. MeMgI (0.10 mL, 3.0 M in diethyl ether,
0.30 mmol) was added to a diethyl ether suspension (8 mL) of
[MesNON]HfCl2 (102 mg, 0.149 mmol) at -30 °C. The reaction
mixture was stirred at room temperature for 40 min, and 1,4-
dioxane (5 drops) was added. Insoluble materials were removed
by filtration through Celite. The filtrate was concentrated in
vacuo until the volume was ∼0.5 mL. The concentrated
solution was kept at -30 °C overnight to give a colorless
crystalline solid. The supernatant was decanted, and the solid
was washed with pentane (1 mL) and dried in vacuo; yield 84
mg (88%): 1H NMR (C6D6) δ 7.50 (d, 2, Aryl), 6.91 (s, 4, Aryl),
6.81 (t, 2, Aryl), 6.50 (t, 2, Aryl), 6.21 (d, 2, Aryl), 2.28 (s, 12,
Meo), 2.16 (s, 6, Mep), 0.40 (s, 6, HfMe); 13C NMR (C6D6) δ
147.24 (CAr), 146.73 (CAr), 138.86 (CAr), 136.74 (CAr), 136.34
(CAr), 130.73 (CArH), 126.74 (CArH), 117.26 (CArH), 115.66
(CArH), 114.67 (CArH), 60.18 (HfMe), 21.40 (Mep), 18.97 (Meo).
Anal. Calcd for C32H36HfN2O: C, 59.76; H, 5.64; N; 4.36.
Found: C, 59.86; H, 5.73; N, 4.26.
[MesNON]HfEt2. EtMgBr (0.1 mL, 3 M in diethyl ether,
0.3 mmol, 2 equiv) was added to a diethyl ether suspension (3
mL) of [MesNON]HfCl2 (103 mg, 0.151 mmol) at -30 °C. The
reaction mixture was stirred at room temperature for 1 h, and
1,4-dioxane (5 drops) was added. Insoluble materials were
removed by filtration through Celite. The pale yellow filtrate
was concentrated in vacuo until the volume was ∼1 mL to give
a colorless crystalline solid. The solution was cooled to -30
°C for several hours to allow for the completion of crystalliza-
tion. The supernatant was decanted, and the crystals were
dried in vacuo; yield 89 mg (88%): 1H NMR (C6D6) δ 7.50 (d,
2, Aryl), 6.91 (s, 4, Aryl), 6.84 (t, 2, Aryl), 6.51 (t, 2, Aryl), 6.23
(d, 2, Aryl), 2.30 (s, 12, Meo), 2.17 (s, 6, Mep), 1.28 (t, 6,
HfCH2CH3), 0.77 (q, 4, HfCH2CH3); 13C NMR (C6D6) δ 147.15
(CAr), 147.04 (CAr), 139.06 (CAr), 136.71 (CAr), 136.18 (CAr),
130.66 (CArH), 126.67 (CArH), 117.34 (CArH), 116.13 (CArH),
114.81 (CArH), 73.34 (HfCH2CH3), 21.36 (Mep), 18.94 (Meo),
12.05 (HfCH2CH3). Anal. Calcd for C34H40HfN2O: C, 60.84; H,
6.01; N; 4.17. Found: C, 60.69; H, 5.92; N, 4.21.
[MesNON]Hf(CH2CHMe2)2. IsobutylMgBr (0.15 mL, 2.0
M in diethyl ether, 0.30 mmol) was added to a diethyl ether
suspension (3 mL) of [MesNON]HfCl2 (103 mg, 0.151 mmol)
at -30 °C. The reaction mixture was stirred at room temper-
ature for 30 min. The solvent was removed in vacuo, and the
solid residue was extracted with pentane (8 mL). The extract
was filtered through Celite, and pentane was removed in vacuo
to give a colorless oil. The oil was cooled to -30 °C overnight
to give a colorless, waxy solid. The solid was washed with
pentane (0.5 mL) and dried in vacuo; yield 86 mg (79%): 1H
NMR (C6D6) δ 7.55 (d, 2, Aryl), 6.92 (s, 4, Aryl), 6.83 (t, 2, Aryl),
6.52 (t, 2, Aryl), 6.22 (d, 2, Aryl), 2.34 (s, 12, Meo), 2.17 (s, 6,
Mep), 2.02 (septet, 2, HfCH2CHMe2), 0.82 (d, 4, HfCH2CHMe2),
0.81 (d, 12, HfCH2CHMe2); 13C NMR (C6D6) δ 147.32 (CAr),
147.15 (CAr), 139.95 (CAr), 136.47 (CAr), 136.22 (CAr), 130.72
(CArH), 126.75 (CArH), 117.45 (CArH), 116.16 (CArH), 114.98
(CArH), 94.96 (HfCH2CHMe2), 30.22 (HfCH2CHMe2), 29.03
(HfCH2CHMe2), 21.32 (Mep), 19.17 (Meo). Anal. Calcd for
C
38H48HfN2O: C, 62.75; H, 6.65; N; 3.85. Found: C, 62.84; H,
6.53; N, 3.77.
[MesNON]Hf(CH2CMe3)2. A diethyl ether solution (2 mL)
of LiCH2CMe3 (23 mg, 0.30 mmol) at -30 °C was added to a
diethyl ether suspension (4 mL) of [MesNON]HfCl2 (100 mg,
0.146 mmol) at -30 °C. The reaction mixture was stirred at
room temperature for 80 min, and all insoluble solids were
removed by filtration through Celite. The solvent was removed
in vacuo to give an off-white solid product; yield 103 mg
(93%): 1H NMR (C6D6) δ 7.56 (d, 2, Aryl), 6.92 (s, 4, Aryl),
6.81 (t, 2, Aryl), 6.50 (t, 2, Aryl), 6.22 (d, 2, Aryl), 2.37 (s, 12,
Meo), 2.17 (s, 6, Mep), 0.96 (s, 4, HfCH2CMe3), 0.93 (s, 18,
HfCH2CMe3); 13C NMR (C6D6) δ 147.43 (CAr), 147.24 (CAr),
142.39 (CAr), 136.19 (CAr), 136.12 (CAr), 130.77 (CArH), 126.82
(CArH), 117.47 (CArH), 116.40 (CArH), 115.29 (CArH), 104.97
(HfCH2CMe3), 37.09 (HfCH2CMe3), 35.26 (HfCH2CMe3), 21.31
(Mep), 19.61 (Meo). Anal. Calcd for C40H52HfN2O: C, 63.60; H,
6.94; N, 3.71. Found: C, 63.46; H, 6.84; N, 3.78.
[MesNON]HfP h 2. PhMgBr (0.1 mL, 3 M in diethyl ether,
0.3 mmol, 2 equiv) was added to a diethyl ether suspension (4
mL) of [MesNON]HfCl2 (103 mg, 0.151 mmol) at -30 °C. The
reaction mixture was stirred at room temperature for 1 h, and
1,4-dioxane (5 drops) was added. Insoluble materials were
removed by filtration through Celite. The yellow filtrate was
concentrated in vacuo until the volume was ∼1 mL. The
solution was cooled to -30 °C overnight to give a pale yellow
crystalline solid. The supernatant was decanted, and the solid
was dried in vacuo; yield 110 mg (95%): 1H NMR (C6D6) δ
7.58 (d, 2, Aryl), 7.52 (d, 4, Aryl), 7.10 (t, 4, Aryl), 6.99 (t, 2,
Aryl), 6.81 (t, 2, Aryl), 6.76 (s, 4, Aryl), 6.55 (t, 2, Aryl), 6.20
(d, 2, Aryl), 2.15 (s, 6, Mep), 2.09 (s, 12, Meo); 13C NMR (C6D6)
δ 205.28 (HfCipso), 147.47 (CAr), 147.35 (CAr), 139.75 (CAr),
137.00 (CAr), 136.52 (CAr), 136.48 (CArH), 130.57 (CArH), 129.61
(CArH), 127.76 (CArH), 126.95 (CArH), 118.08 (CArH), 116.45
(CArH), 115.07 (CArH), 21.29 (Mep), 19.14 (Meo). Anal. Calcd
for C42H40HfN2O: C, 65.75; H, 5.25; N, 3.65. Found: C, 65.55;
H, 5.20; N, 3.59.
Rea ction betw een 1-Hexen e a n d [MesNON]Zr Me2 Ac-
tiva ted w ith [HNMe2P h ][B(C6F 5)4]. A C6D5Br solution (0.3
mL) of [MesNON]ZrMe2 (5 mg, 9 µmol) at -30 °C was added
to a C6D5Br solution (0.4 mL) of [HNMe2Ph][B(C6F5)4] (7 mg,
8.7 µmol) at -30 °C. The solution color changed immediately
from colorless to light yellow. The reaction mixture was briefly
warmed to 20 °C to allow for the dissolution of the anilinium
salt and kept at 0 °C. 1-Hexene (60 equiv) was added to the
solution at 0 °C. The reaction was monitored by 1H NMR
spectroscopy, which showed ∼50% consumption of 1-hexene
in 4 h.
Rea ction betw een 1-Hexen e a n d [MesNON]Zr Me2 Ac-
tiva ted w ith [P h 3C][B(C6F 5)4]. A C6D5Br solution (0.3 mL)
of [MesNON]ZrMe2 (10 mg, 18 µmol) at -30 °C was added to
a C6D5Br solution (0.4 mL) of [Ph3C][B(C6F5)4] (16 mg, 17 µmol)
at -30 °C. The orange solution was kept at 0 °C. 1-Hexene
(60 equiv) was added at 0 °C. The reaction was monitored by
1H NMR spectroscopy, which showed complete consumption
of 1-hexene in 10 min.
Ack n ow led gm en t. R.R.S. thanks the Department
of Energy (DE-FG02-86ER13564) for supporting this
research.
Su ppor tin g In for m ation Available: Fully labeled ORTEP
drawings, atomic coordinates, bond lengths and angles, and
anisotropic displacement parameters for [MesNON]Hf(CH2-
CMe3)2. This material is available free of charge via the
Internet at http://pubs.acs.org.
OM0000921