Group 4 metal complexes of fhiorous (Di)alkoxide-(Di)imino ligands: synthesis, structure, olefin polymerization catalysis, and decomposition pathways

Article abstract of DOI:10.1021/om8009409

The coordination chemistry of fluorous (di)alkoxide-(di)imino ligands onto Ti(IV), Zr(IV), and Hf(IV) centers has been studied. The diimino-diol [(CF ₃)₂C(OH)CH₂C(Me)=NCH₂-]₂ ({ON^EtNO}H

Full text of DOI:10.1021/om8009409

606
Organometallics 2009, 28, 606–620
Group 4 Metal Complexes of Fluorous (Di)Alkoxide-(Di)Imino
Ligands: Synthesis, Structure, Olefin Polymerization Catalysis, and
Decomposition Pathways
Nicolas Marquet,† Evgueni Kirillov,† Thierry Roisnel,† Abbas Razavi,# and
Jean-Franc¸ois Carpentier*,†
Catalysis and Organometallics, UMR 6226 Sciences Chimiques de Rennes, CNRS-UniVersity of Rennes 1,
35042 Rennes Cedex, France, and Total Petrochemicals Research, Zone Industrielle C,
7181 Feluy, Belgium
ReceiVed September 29, 2008
The coordination chemistry of fluorous (di)alkoxide-(di)imino ligands onto Ti(IV), Zr(IV), and Hf(IV)
centers has been studied. The diimino-diol [(CF3)2C(OH)CH2C(Me)dNCH2-]2 ({ONEtNO}H2) reacts
selectively with Ti(OiPr)2Cl2 and Zr(CH2Ph)4 to give the corresponding complexes {ONEtNO}TiCl2 (1)
and {ONEtNO}Zr(CH2Ph)2 (2), with concomitant alcohol and alkane elimination, respectively. Reactions
of the imino-alcohols (CF3)2C(OH)CH2C(R1)dNR2 ({ONR1,R2}H; R1 ) Me, Ph; R2 ) Ph, CH2Ph) with
Ti(OiPr)4 and M(CH2Ph)4 (M ) Zr, Hf) gave the corresponding complexes Ti(OiPr)2{ONR1,R2}2 (3a,b)
and M(CH2Ph)2{ONR1,R2}2 (M ) Zr, 7a,b,c; M ) Hf, 8a,b). Dibenzyl complexes 7 and 8 decompose
above -30 °C by abstraction of a hydrogen from the methylene ligand backbone by a benzyl group to
give M(CH2Ph){ONR1,R2}{ON-R1,R2} complexes (M ) Zr, 9a-c; M ) Hf, 10a), in which a ligand unit
({ON-R1,R2}) has been transformed to an R,ꢀ-unsaturated amido-alkoxy dianionic moiety. A slightly
different process was observed for the pentafluorophenyl system Zr(CH2Ph)2{ONMe,ArF}2 (ArF ) C6F5;
7d), which ultimately yielded the benzyl-free complex Zr{ONMe,ArF}2{ON-Me,ArF} (11). Single-crystal
X-ray diffraction studies revealed that complexes 1, 3a, 7a, 7b, 7d, 8a, and 11 are mononuclear in the
solid state and adopt either C1- or mostly C2V-symmetric, distorted octahedral structures with planar
coordination of the (di)imino-di(alkoxide) ligands. Multinuclear NMR studies indicate that most of the
complexes adopt also a C2V-symmetric structure in solution. Dichloride complexes ZrCl2{ONR1,R2}2 (R1
) Me, Ph; R2 ) Ph, C6F5; 12a-c) were prepared by alkane elimination or salt metathesis. When activated
by MAO, 3a,b and 12a-c lead to active but very unstable ethylene polymerization catalysts that afford
very high molecular weight linear polyethylenes.
strategy to overcome this difficulty. Introduction of electron-
withdrawing CF3 groups R to the alkoxide generates intra- and
intermolecular repulsions, as well as a less basic alkoxide
O-atom, and as a result, a less distinct bridging tendency is
observed.1,3 Following this line, we have described some bi-
and tetradentate fluorous (di)alkoxide-(di)amino ligand systems
that proved to be effective for preparing well-defined complexes
of oxophilic metal centers such as Y(III), Zr(IV), and Al(III),
and in turn developing valuable applications in polymerization
catalysis.4 Recently, we launched another class of bi- and
tetradentate fluorous (di)alkoxide-(di)imino ligands,5,6 which are
Introduction
Alkoxides are hard, electronegative π-donor ligands, which
are quite attractive because they offer strong metal-oxygen
bonds that are expected to stabilize complexes of a variety of
electropositive metals.1 Also, considerable variation in steric
and electronic properties is possible thanks to the great variety
of these ligands conveniently obtained from alcohols. These
features have given alkoxides a key place in modern coordina-
tion chemistry of early transition and main group metals (groups
3-5, 13), in particular in the recent search for new-generation
polymerization catalysts.2 The synthetic chemistry of early
transition metal complexes based on simple alkoxides proved
to be, however, often complicated.1 This is largely due to the
high tendency of the relatively more basic alkoxide ligands (as
compared to aryloxides) to act as bridging ligands, eventually
resulting in (highly) agglomerated structures. The use of highly
stable fluorous tertiary alcohol ligands affords an efficient
(2) For reviews and leading articles on “post-metallocene” complexes
of groups 3-5 and the lanthanides related to polymerization, see: (a)
Britovsek, G. J. P.; Gibson, V. C.; Wass, D. F. Angew. Chem., Int. Ed.
1999, 38, 428. (b) Edelmann, F. T.; Freckmann, D. M. M.; Schumann, H.
Chem. ReV. 2002, 102, 1851. (c) Gibson, V. C.; Spitzmesser, S. K. Chem.
ReV. 2003, 103, 283. (d) Gromada, J.; Mortreux, A.; Carpentier, J.-F. Coord.
Chem. ReV. 2004, 248, 397. (e) Corradini, P.; Guerra, G.; Cavallo, L. Acc.
Chem. Res. 2004, 37, 231. (f) Kol, M.; Tshuva, E. Y.; Goldschmidt, Z.
ACS Symp. Ser. 2003, 857, 62. (g) Kol, M.; Segal, S.; Groysman, S. In
StereoselectiVe Polymerization with Single-Site Catalysts; CRC Press LLC:
Boca Raton, FL, 2008; pp 345-361. (h) Gueta-Neyroud, T.; Tumanskii,
B.; Kapon, M.; Eisen, M. S. Macromolecules 2007, 40, 5261. (i) Okuda, J.
Stud. Surf. Sci. Catal. 2007, 172, 11. (j) Matsugi, T.; Fujita, F. Chem. Soc.
ReV. 2008, 37, 1264. (k) Coates, G. W.; Hustad, P. D.; Reinartz, S. Angew.
Chem., Int. Ed. 2002, 41, 2236. (l) Domski, G. J.; Rose, J. M.; Coates,
G. W.; Bolig, A. D.; Brookhart, M. Prog. Polym. Sci. 2007, 32, 30. (m)
Chan, M. C. W.; Kui, S. C. F.; Cole, J. M.; McIntyre, G. J.; Matsui, S.;
Zhu, N.; Tam, K. H. Chem.-Eur. J. 2006, 12, 2607.
* Corresponding author. Fax: (+33)(0)223-236-939. E-mail: jean-
francois.carpentier@univ-rennes1.fr.
† CNRS-University of Rennes 1.
# Total Petrochemicals Research.
(1) (a) Bradley, D. C.; Mehrotra, R. M.; Rothwell, I. P.; Singh, A. Alkoxo
and Aryloxo DeriVatiVes of Metals; Academic Press: London, 2001. (b)
Mehrotra, R. M.; Singh, A. Prog. Inorg. Chem. 1997, 46, 239. (c) Hubert-
Pfalzgraf, L. G. Coord. Chem. ReV. 1998, 178-180, 967. (d) Piers, W. E.;
Emslie, D. J. H. Coord. Chem. ReV. 2002, 131, 233–234. (e) Edelmann,
F. T.; Freckmann, D. M. M.; Schumann, H. Chem. ReV. 2002, 102, 1851.
10.1021/om8009409 CCC: $40.75
2009 American Chemical Society
Publication on Web 01/02/2009

Group 4 Metal Complexes of Fluorous Ligands
Organometallics, Vol. 28, No. 2, 2009 607
Chart 1. {ONR1,R2}H and {ONEtNO}H2 Pro-ligands Used in
This Study
Figure 1. Possible isomers for octahedral {ONEtNO}MX2 com-
plexes. The cis/trans descriptors refer to the arrangement of alkoxide
and X ligands, respectively. Note that the imino ligands must be
cis. Only one of the possible enantiomers (Λ, ∆, depending on the
absolute configuration of the metal)14 is depicted.
structurally reminiscent of aryloxide-bearing salen7 and pheno-
moisture-sensitive12 and were characterized in the solid state
by elemental analysis and X-ray diffraction studies for some of
xyimine2j,8,9 ligands. Those {ONR1,R2
}
and {ONEtNO}2-
-
ligands (Chart 1) enabled the preparation of discrete complexes
of trivalent metals such as Y(III), La(III),10 and Al(III),11
conferring a high electrophilicity to the metal centers, that
proved to be useful in the controlled ring-opening polymeriza-
tion of cyclic esters.
1
them, and in solution by variable-temperature H, 13C, and 19F
NMR spectroscopy.
Synthesis and Structures of Neutral {ONEtNO}MX2
Complexes. First investigations were carried out using the
tetradentate ligand {ONEtNO}2-. Assuming an ideal octahedral
arrangement and flexibility of the {ONEtNO}2- ligand frame-
work, three {ONEtNO}MX2 isomeric structures are possible
(A-C, Figure 1), which differ in the arrangement (cis vs trans)
of the pairs of alkoxide and X ligands.13
We report in this article the preparation, structural charac-
terization, and reactivity of tetravalent group 4 metal complexes
supported by {ONR1,R2}- and {ONEtNO}2- ligands. Preliminary
studies on the catalytic performances of such discrete complexes
in ethylene polymerization are also reported, and discussed in
connection with some decomposition pathways.
The 1:1 reaction between diol {ONEtNO}H2 and Ti(OiPr)2Cl2,
in situ-generated from TiCl4 and Ti(OiPr)4,15 proceeded selec-
tively at room temperature to yield {ONEtNO}TiCl2 (1), as is
(7) (a) Jacobsen, E. N. Catalytic Asymmetric Synthesis; OjimaI., Ed.;
VCH: Weinheim, 1993; p 159. (b) Jacobsen, E. N. ComprehensiVe
Organometallic Chemistry II; Wilkinson, G.; Stone, F. G. A.; Abel, E. W.;
Hegedus, L. S., Eds.; Pergamon Press: New York, 1995; Vol. 12,Chapter
11.1. (c) Larrow, J. F.; Jacobsen, E. N. Top. Organomet. Chem. 2004, 6,
123. (d) Cozzi, P. G. Chem. Soc. ReV. 2004, 33, 410. (e) Katsuki, T. Chem.
Soc. ReV. 2004, 33, 437. (f) Atwood, D. A.; Harvey, M. J. Chem. ReV.
2001, 101, 37.
Results and Discussion
Several routes to Ti, Zr, and Hf complexes based on a variety
of bidentate monoanionic {ONR1,R2}- ligands, as well as on the
tetradentate dianionic {ONEtNO}2- ligand, have been explored:
(a) σ-bond metathesis (alcoholysis) reactions between the
alcohol/diol pro-ligands {ONR1,R2}H and {ONEtNO}H2 and an
appropriate homo- or heteroleptic metal precursor, enabling
either alkane or alcohol elimination; (b) salt elimination reactions
between {ONR1,R2}M alkali metal salts, either preliminary
prepared or in situ-generated, and a MCl4(THF)n precursor.
These results are discussed hereafter and summarized in
Schemes 1-7. The prepared neutral complexes are all air- and
(8) (a) Makio, H.; Fujita, T. Macromol. Rapid Commun. 2007, 28, 698.
(b) Terao, H.; Ishii, S.; Saito, J.; Matsuura, S.; Mitani, M.; Nagai, N.; Tanaka,
H.; Fujita, T. Macromolecules 2006, 39, 8584. (c) Nakayama, Y.; Saito, J.;
Bando, H.; Fujita, T. Chem.-Eur. J. 2006, 12, 7546. (d) Saito, J.; Suzuki,
Y.; Makio, H.; Tanaka, H.; Onda, M.; Fujita, T. Macromolecules 2006, 39,
4023. (e) Mitani, M.; Nakano, T.; Fujita, T. Chem.-Eur. J. 2003, 9, 2396.
(f) Mitani, M.; Furuyama, R.; Mohri, J.; Saito, J.; Ishii, S.; Terao, H.;
Nakano, T.; Tanaka, H.; Fujita, T. J. Am. Chem. Soc. 2003, 125, 4293. (g)
Makio, H.; Kashiwa, N.; Fujita, T. AdV. Synth. Catal. 2002, 344, 477. (h)
Mitani, M.; Furuyama, R.; Mohri, J.; Saito, J.; Ishii, S.; Terao, H.; Kashiwa,
N.; Fujita, T. J. Am. Chem. Soc. 2002, 124, 7888. (i) Mitani, M.; Mohri, J.;
Yoshida, Y.; Saito, J.; Ishii, S.; Tsuru, K.; Matsui, S.; Furuyama, R.; Nakano,
T.; Tanaka, H.; Kojoh, S.; Matsugi, T.; Kashiwa, N.; Fujita, T. J. Am. Chem.
Soc. 2002, 124, 3327. (j) Saito, J.; Mitani, M.; Mohri, J.; Yoshida, Y.;
Matsui, S.; Ishii, S.; Kojoh, S.; Kashiwa, N.; Fujita, T. Angew. Chem., Int.
Ed. 2001, 40, 2918. (k) Matsui, S.; Mitani, M.; Saito, J.; Tohi, Y.; Makio,
H.; Matsukawa, N.; Takagi, Y.; Tsuru, K.; Nitabaru, M.; Nakano, T.;
Tanaka, H.; Kashiwa, N.; Fujita, T. J. Am. Chem. Soc. 2001, 123, 6847.
(9) (a) Mason, A. F.; Coates, G. W. J. Am. Chem. Soc. 2004, 126, 10798.
(b) DeRosa, C.; Circelli, T.; Auriemma, F.; Mathers, R. T.; Coates, G. W.
Macromolecules 2004, 37, 9034. (c) Mason, A. F.; Coates, G. W. J. Am.
Chem. Soc. 2004, 126, 16326. (d) Reinartz, S.; Mason, A. F.; Lobkovsky,
E. B.; Coates, G. W. Organometallics 2003, 22, 2542. (e) Hustad, P. D.;
Tian, J.; Coates, G. W. J. Am. Chem. Soc. 2002, 124, 3614. (f) Tian, J.;
Coates, G. W. Angew. Chem., Int. Ed. 2000, 39, 3626.
(3) For selected examples of early transition metal complexes bearing
fluorous alkoxide ligands: (a) Bradley, D. C.; Chudszynska, H.; Hursthouse,
M. B.; Motevalli, M. Polyhedron 1994, 12, 1907. (b) Bradley, D. C.;
Chudszynska, H.; Hursthouse, M. B.; Motevalli, M. Polyhedron 1994, 13,
7. (c) Samuels, J. A.; Lobkovsky, E. B.; Streib, W. E.; Folting, K.; Huffman,
J. C.; Zwanziger, J. W.; Caulton, K. G. J. Am. Chem. Soc. 1993, 115, 5093.
(d) Tsukuhara, T.; Swenson, D. C.; Jordan, R. F. Organometallics 1997,
16, 3303. (e) Fujimura, O.; Grubbs, R. J. J. Am. Chem. Soc. 1996, 118,
2499. (f) Fujimura, O.; De la Mata, F. J.; Grubbs, R. H. Organometallics
1996, 15, 1865.
(4) (a) Lavanant, L.; Chou, T.-Y.; Chi, Y.; Lehmann, C. W.; Toupet,
L.; Carpentier, J.-F. Organometallics 2004, 23, 5450. (b) Amgoune, A.;
Lavanant, L.; Thomas, C. M.; Chi, Y.; Welter, R.; Dagorne, S.; Carpentier,
J.-F. Organometallics 2005, 24, 6279. (c) Kirillov, E.; Lavanant, L.; Thomas,
C. M.; Roisnel, T.; Chi, Y.; Carpentier, J.-F. Chem.-Eur. J. 2007, 13, 923.
(5) Marquet, N.; Grunova, E.; Kirillov, E.; Bouyahyi, M.; Thomas,
C. M.; Carpentier, J.-F. Tetrahedron 2008, 64, 75.
(10) Grunova, E.; Kirillov, E.; Roisnel, T.; Carpentier, J.-F. Organo-
metallics 2008, 27, 5691.
(11) Bouyahyi, M.; Grunova, E.; Marquet, N.; Kirillov, E.; Thomas,
C. M.; Roisnel, T.; Carpentier, J.-F. Organometallics 2008, 22, 5815-5825.
(12) Benzyl complexes of zirconium and hafnium proved also to be
sensitive when exposed to light, as solutions in hydrocarbons.
(13) Sanz, M.; Cuenca, T.; Cuomo, C.; Grassi, A. J. Organomet. Chem.
2006, 691, 3816, and references therein.
(14) Purcell, K. F.; Kotz, J. C. In Inorganic Chemistry; Saunders Co.:
Philadelphia, 1977; pp 368-648.
(15) Gothelf, K. V.; Jorgensen, K. A. J. Org. Chem. 1994, 59, 5687.
(6) Fluorous alkoxy-imino ligands were first prepared in the coordination
sphere of metals ions, i.e., Cu2+, Ni2+, Co2+, Ce3+, Ce4+ by the template
condensation of primary (di)amines with the fluorous ꢀ-ketol
MeC(dO)CH2C(CF3)2OH; see: (a) Martin, J. W. L.; Willis, C. J. Can.
J. Chem. 1977, 55, 2459. (b) Konefal, E.; Loeb, S. J.; Stephan, D. W.;
Willis, C. J. Inorg. Chem. 1984, 23, 538, and references therein.

608 Organometallics, Vol. 28, No. 2, 2009
Marquet et al.
Scheme 1
Figure 2. ORTEP view of {ONEtNO}TiCl2 (1) (ellipsoids drawn
at the 50% probability level; all hydrogen atoms have been omitted
for clarity). Selected bond lengths (Å) and angles (deg): Ti(1)-O(21),
1.819(3);Ti(1)-O(11),1.822(3);Ti(1)-N(17),2.173(4);Ti(1)-N(27),
2.182(4); Ti(1)-Cl(1), 2.3368(14); Ti(1)-Cl(2), 2.3372(15);
O(21)-Ti(1)-O(11), 108.61(14); O(21)-Ti(1)-N(17), 163.85(14);
O(11)-Ti(1)-N(17), 87.36(14); O(21)-Ti(1)-N(27), 87.38(13);
O(11)-Ti(1)-N(27), 163.99(13); N(17)-Ti(1)-N(27), 76.63(13);
O(21)-Ti(1)-Cl(1), 93.35(11); O(11)-Ti(1)-Cl(1), 93.36(11);
N(17)-Ti(1)-Cl(1), 83.07(10); N(27)-Ti(1)-Cl(1), 84.84(11);
O(21)-Ti(1)-Cl(2), 95.41(11); O(11)-Ti(1)-Cl(2), 95.35(11);
N(17)-Ti(1)-Cl(2), 85.15(10); N(27)-Ti(1)-Cl(2), 83.42(11);
Cl(1)-Ti(1)-Cl(2), 165.00(6).
common of simple exchange reactions between titanium alkox-
ide complexes and alcohols.1 Similarly, the dibenzyl complex
{ONEtNO}Zr(CH2Ph)2 (2) was prepared by alcoholysis of
Zr(CH2Ph)4 (Scheme 1). Both complexes are sparingly soluble
in aliphatic hydrocarbons (pentane, hexanes) but readily soluble
in aromatic hydrocarbons (benzene, toluene) and chlorinated
solvents (CH2Cl2), in which they are stable for at least weeks
at room temperature.
Crystals of 1 suitable for X-ray diffraction were obtained from
a toluene solution. The solid-state structure of 1 (Figure 2)
features a monomeric molecule with a six-coordinated metal
center and equatorial coordination of the {ONEtNO}2- ligand,
in a Salen-like fashion, that is a type A structure (Figure 1).
We have observed a similar planar coordination mode when
exploring the aluminum chemistry of this ligand, although the
square-pyramidal (sqp) geometry structures of these Al com-
plexes are more distorted toward a trigonal-bipyramidal (tbp)
geometry.7f,11 However, the most worthy and meaningful
structural comparison for these new diimino-diolate complexes
is undoubtedly with group 4 metal salen (i.e., diimino-
bisphenolate) complexes, since both incorporate similar ligand
frameworks. In fact, the metrical data in 1, i.e., bond distances
Ti-O (1.819(3)-1.822(3) Å), Ti-N (2.173(4)-2.182(4) Å),
and Ti-Cl (2.3368(14)-2.3372(15) Å) and the corresponding
bond angles O-Ti-O (108.61(14)°), N-Ti-N (76.63(13)°),
and Cl-Ti-Cl (165.00(6)°) (Figure 1), compare very well with
those observed in related ethylene- and 1,2-cyclohexylene-
bridged-Salen dichlorotitanium complexes [Ti-O (1.816-1.844
Å), Ti-N (2.121-2.171 Å), Ti-Cl (2.326-2.370 Å), O-Ti-O
(110.05-113.27°), N-Ti-N (75.29-78.91°), Cl-Ti-Cl
(168.21-171.42°)].16 The Ti, O, O, N, N atoms are almost
perfectly coplanar (maximum deviation from mean plane: 0.022
Å). Also, the six-membered metallacycles involving the imino-
alkoxide ligand in 1 appear quite planar (deviation from the
mean plane Ti-N-C-C-C-O: Ti(1), -0.076; O(11), +0.059,
C(11), +0.204; C(14), -0.314; C(15), +0.072; N(17), +0.154
Å). These data indicate that substitution of a phenoxide group
for a bis(trifluoromethyl)alkoxide group did not affect signifi-
cantly the coordination mode, although there is no more
conjugation with the imino moiety in complex 1. On the other
hand, the solid-state structure of 1 differs dramatically from that
observed for the related fluorous dialkoxide-diamino complex
{CH2NMeCH2C(CF3)2O}2TiCl2 and {CH2NMeCH2C(CF3)2-
O}2Zr(CH2Ph)2.4a In fact, the latter complexes adopt also a
distorted octahedral geometry but in which the oxygen atoms
of the dialkoxide ligand are trans and the X ligands (X ) Cl,
CH2Ph, respectively) are cis; that is a type B structure (Figure
1). This observation suggests that substitution of an amino for
an imino group is more crucial in terms of ligand framework
flexibility than the aforementioned modification (substitution of
Figure 3. Possible isomers for octahedral {ONR1,R2}MX2 com-
plexes. The cis/trans descriptors refer to the arrangement of imino,
alkoxide, and X ligands, respectively. Enantiomers of C2- and C1-
symmetric isomers are not depicted. R1 and R2 substituents are not
shown for the sake of clarity.
a phenoxide group for a bis(trifluoromethyl)alkoxide group) and
does not induce significant constraint within the six-membered
N-M-O metallacycles.
In agreement with the structure observed in the solid state,
the 1H, 13C, and 19F NMR data for 1 in CD2Cl2 at room
temperature contain a single set of resonances, consistent with
an average C2V-symmetric type A structure retained in solution.
In particular, the 1H NMR spectrum contains three singlet
resonances for the CH3, CH2CdN, and NCH2 groups, respec-
tively, while only one singlet resonance is observed for the
OC(CF3)2 moieties in the 19F{1H} NMR spectrum.17 No
fluxional dynamic process associated with possible isomerization
1
of the ligand backbone in 1 was observed by VT H NMR in
the temperature range -60 to 60 °C.
Single crystals of 2 suitable for X-ray diffraction studies could
not be obtained, and this complex was characterized in solution
by NMR spectroscopy. The 1H, 13C, and 19F NMR data for 2 in

Group 4 Metal Complexes of Fluorous Ligands
Organometallics, Vol. 28, No. 2, 2009 609
Scheme 2
CD2Cl2 at room temperature are very similar to those observed
for 1 and include a sharp singlet resonance in the 19F{1H} NMR
1
spectrum, as well as three singlets in the H spectrum for the
ligand hydrogens. In addition, the benzyl groups appear as a
1
single singlet resonance in both the H and 13C NMR spectra.
These data are consistent with an average C2V-symmetric type
A structure, with equatorial coordination of the {ONEtNO}2-
ligand, as observed for 1.17
Synthesis, Structures, and Reactivity of Neutral
{ONR,R}MX2 Complexes. We turned our attention next to the
coordination of monoanionic bidentate ligands {ONR1,R2}-. In
this case, up to five isomeric structures (without considering
enantiomers) can be envisaged (Figure 3).13
Figure 4. ORTEP view of Ti(OiPr)2{ONMe,Ph}2 (3a) (ellipsoids
drawn at the 50% probability level; all hydrogen atoms have been
omitted for the sake of clarity; only one (#2) of the two independent
molecules found in the unit cell is depicted). Selected bond lengths
(Å) and angles (deg) [data in square brackets refer to the second
independent molecule (#1)]: Ti(2)-O(20), 1.7791(14) [1.8066(14)];
Ti(2)-O(13), 1.8337(13) [1.8128(13)]; Ti(2)-O(4), 1.8947(13)
[1.9109(13)]; Ti(2)-O(29), 1.9537(13) [1.9741(13)]; Ti(2)-N(36),
2.2817(17) [2.2794(16)]; Ti(2)-N(42), 2.3428(17) [2.3744(17)];
O(20)-Ti(2)-O(13), 96.88(6) [94.40(6)]; O(20)-Ti(2)-O(4),
96.77(6) [94.49(6)]; O(13)-Ti(2)-O(4), 98.37(6) [99.58(6)];
O(20)-Ti(2)-O(29), 98.92(6) [95.85(6)]; O(13)-Ti(2)-O(29),
160.54(6) [163.49(6)]; O(4)-Ti(2)-O(29), 90.99(6) [92.49(5)];
O(20)-Ti(2)-N(36), 91.75(6) [97.71(6)]; O(13)-Ti(2)-N(36),
86.91(6) [84.22(6)]; O(4)-Ti(2)-N(36), 169.34(6) [166.91(6)];
O(29)-Ti(2)-N(36), 81.34(6) [81.61(5)]; O(20)-Ti(2)-N(42),
177.95(6) [175.93(5)]; O(13)-Ti(2)-N(42), 81.20(6) [84.13(6)];
O(4)-Ti(2)-N(42), 82.84(6) [82.04(6)]; O(29)-Ti(2)-N(42),
83.10(6) [86.46(5)]; N(36)-Ti(2)-N(42), 88.86(6) [85.93(6)].
Isopropoxide and Chloride Complexes of Titanium. Due
to easiness of alcohol elimination processes1 and their efficiency
demonstrated in the above-mentioned formation of {ONEtNO}-
TiCl2 (1), this route was also explored to prepare related
diisopropoxide titanium complexes based on monoanionic
bidentate ligands {ONR1,R2}-. In fact, alcoholysis of Ti(OiPr)4
with 2 equiv of fluorinated alcohol-imines {ONR1,R2}H (R1 )
CH3, Ph; R2 ) Ph) proceeds fast and selectively, at room
temperature in toluene or benzene, to afford the corresponding
Ti(OiPr)2{ONR1,R2}2 complexes 3a and 3b, with concomitant
release of 2 equiv of 2-propanol (Scheme 2). Complexes 3a
and 3b were isolated in 63% and 64% yields, respectively, and
are both colorless compounds, readily soluble in most common
organic solvents, and thermally stable both in solution and in
the solid state in the absence of air.
Crystals of 3a suitable for X-ray diffraction were grown from
a toluene/hexane solution. The molecular structure of 3a (Figure
4) features a monomeric complex in a distorted octahedral
geometry, with a cis,cis,cis arrangement of the nitrogen ligand
atoms, oxygen ligand atoms, and isopropoxide groups, which
is a type H structure (Figure 3). The Ti-O (1.894-1.974(1)
Å) and Ti-N (2.279-2.374(2) Å) bonds involving the ligand
atoms in 3a are significantly longer than those observed in 1
(Videsupra;Figure2)andinrelatedtitanium-Salencomplexes.16,18
Also, the O-Ti-N angles (81.34(6)-82.84(6)°) in the six-
membered metallacycles of 3a are smaller than those in 1
(87.36(14)-87.38(13)°). Those differences in metrical data
probably reflect, in main part, the influence of the bridging unit
in between the two alkoxy-imino moieties and possibly the trans
influence of ligands as well. On the other hand, these bond
distances and bond angles in 3a compare well with those found
in diisopropoxide and other dialkoxide titanium complexes
supported by phenoxy-imine ligands (Ti-O, 1.895-1.975 Å;
Ti-N, 2.228-2.340 Å; O-Ti-N, 79.73-82.34°).19 Both the
Scheme 3

610 Organometallics, Vol. 28, No. 2, 2009
Marquet et al.
Figure 6. ORTEP view of TiCl(OiPr){ONPh,Ph}2 (5) (ellipsoids
drawn at the 50% probability level; all hydrogen atoms have been
omitted for the sake of clarity). Selected bond lengths (Å) and angles
(deg): Ti(1)-O(7), 1.749(2); Ti(1)-O(3), 1.8519(19); Ti(1)-O(6),
1.884(2); Ti(1)-N(13), 2.260(2); Ti(1)-Cl(2), 2.3428(9);
Ti(1)-N(17), 2.376(2); O(7)-Ti(1)-O(3), 96.31(9); O(7)-Ti(1)-
O(6), 99.16(9); O(3)-Ti(1)-O(6), 93.49(8); O(7)-Ti(1)-N(13),
91.99(9); O(3)-Ti(1)-N(13), 171.32(9); O(6)-Ti(1)-N(13),
82.65(9); O(7)-Ti(1)-Cl(2), 95.03(8); O(3)-Ti(1)-Cl(2),
92.62(6); O(6)-Ti(1)-Cl(2), 163.82(7); N(13)-Ti(1)-Cl(2),
89.17(7); O(7)-Ti(1)-N(17), 179.61(10); O(3)-Ti(1)-N(17),
83.36(8); O(6)-Ti(1)-N(17), 80.67(8); N(13)-Ti(1)-N(17),
88.34(8); Cl(2)-Ti(1)-N(17), 85.18(6).
Figure 5. ORTEP view of TiCl2(OiPr){ONMe,Ph} · iPrOH (4 · iPrOH)
(ellipsoids drawn at the 50% probability level; all hydrogen atoms
except H(111) have been omitted for the sake of clarity). Selected
bond lengths (Å) and angles (deg): Ti(1)-O(11), 1.7440(11);
Ti(1)-O(21), 1.8411(11); Ti(1)-O(101), 2.1338(12); Ti(1)-N(31),
2.2967(13); Ti(1)-Cl(2), 2.3206(5); Ti(1)-Cl(1), 2.4179(5);
O(11)-Ti(1)-O(21), 96.81(5); O(11)-Ti(1)-O(101), 93.06(5);
O(21)-Ti(1)-O(101), 169.32(5); O(11)-Ti(1)-N(31), 170.38(5);
O(21)-Ti(1)-N(31), 83.90(5); O(101)-Ti(1)-N(31), 85.68(5);
O(11)-Ti(1)-Cl(2), 101.71(4); O(21)-Ti(1)-Cl(2), 94.38(4);
O(101)-Ti(1)-Cl(2), 87.54(3); N(31)-Ti(1)-Cl(2), 87.78(4);
O(11)-Ti(1)-Cl(1), 90.48(4); O(21)-Ti(1)-Cl(1), 94.94(4);
O(101)-Ti(1)-Cl(1), 80.90(3); N(31)-Ti(1)-Cl(1), 79.90(3);
Cl(2)-Ti(1)-Cl(1), 163.654(18).
turned out to be mixtures of the mixed chloride-isopropoxide
complex TiCl(OiPr){ONPh,Ph}2 (5)21 and the zwitterionic com-
plex [TiCl3{ONPh,Ph}{ONHPh,Ph}] (6) (Scheme 3). In the latter
complex, one of the two ligand units is coordinated by a single
σ-alkoxide group, while its imino function has been protonated.
Complexes 4 · iPrOH, 5, and 6 were structurally characterized
by X-ray diffraction studies (Figures 5 -7 Table 1). The main
Ti-{ONR1,R2}, Ti-OiPr, and Ti-Cl bond distances and related
angles in these three complexes are quite similar to those
discussed above for complexes 1 and 3a. As in the case of 3a,
complex 5 features a type H structure. Peculiarities in 4 · iPrOH
six-membered metallacycles appear rather planar, apart from
the “central” CH2 carbon that deviates significantly from the
mean plane Ti-N-C-C-C-O (C(70), 0.154 Å; C(59), 0.265
Å; all other deviations in the range 0.003-0.117 Å).
1
The H, 13C, and 19F NMR data for 3a and 3b, in C6D6 or
CD2Cl2 at room temperature, are very similar. For both
complexes, a single sharp singlet resonance in the 19F{1H} NMR
spectrum as well as three singlets in the 1H NMR spectrum for
the CH3, CH2CdN, and NCH2 hydrogens in the ligand are
observed. No change is observed in the low-temperature (-50
°C) 1H NMR spectrum of 3a and 3b in CD2Cl2. These features,
which are confirmed in the 13C NMR spectra, are consistent
with the existence of a single C2V-symmetric structure on the
NMR time scale17 (type D, Figure 3) and indicate that the solid-
state structure observed for 3a is not retained in solution.
Similar alcoholysis reactions were investigated using in situ-
generated Ti(OiPr)2Cl2 instead of Ti(OiPr)4 in an attempt to
prepare the corresponding dichloride complexes.20 However, in
contrast with the clean formation of 1 and 3a,b, those reactions
proved to be not as selective as expected. The reaction of 2
equiv of {ONMe,Ph}H with Ti(OiPr)2Cl2 led to the immediate
precipitation of the adduct TiCl2(OiPr){ONMe,Ph} · iPrOH (4 · iPr-
OH), which results obviously from the alcoholysis of a single
isopropoxide group (Scheme 3). Once isolated and dried under
vacuum, this complex rapidly loses its coordinated 2-propanol
molecule to give 4, as confirmed by NMR spectroscopy. Change
of the reaction conditions (prolonged heating, solvent) did not
allow accessing the targeted TiCl2{ONMe,Ph}2 complex. On the
other hand, repeated reactions of 2 equiv of {ONPh,Ph}H with
Ti(OiPr)2Cl2 led systematically to complex mixtures of com-
(16) (a) Tararov, V. I.; Hibbs, D. E.; Hursthouse, M. B.; Ikonnikov,
N. S.; Malik, K. M. A.; North, M.; Orizu, C.; Belokon, Y. N. Chem.
Commun. 1998, 387. (b) Gilli, G.; Cruickshank, D. W. J.; Beddoes, R. L.;
Mills, O. S. Acta Crystallogr., B Struct. Crystallogr. Cryst. Chem. 1972,
28, 1889. (c) Repo, T.; Klinga, M.; Leskela, M.; Pietikainen, P.; Brunow,
G. Acta Crystallogr. C: Cryst. Struct. Commun. 1996, 52, 2742. (d) Kim,
I.; Ha, Y. S.; Zhang, D. F.; Ha, C.-S.; Lee, U. Macromol. Rapid Commun.
2004, 25, 1319. (e) Choudhary, N. F.; Hitchcock, P. B.; Leigh, G. J. Inorg.
Chim. Acta 2000, 306, 24. (f) Kelly, D. G.; Toner, A. J.; Walker, N. M.;
Coles, S. J.; Hursthouse, M. B. Polyhedron 1996, 15, 4307.
(17) In a C2-symmetric environment such as in structure B (Figure 1),
D, or E (Figure 3), two doublets are expected for the diastereotopic
hydrogens of the CHH ligand unit adjacent, as well as for the diastereotopic
hydrogens of CHHPh groups in dibenzyl complexes 7 and 8. Also, the 19
F
NMR spectrum would feature two quartets for the nonequivalent
C(CF3)(CF3) groups; see refs 4a,b.
(18) Gregson, C. K. A.; Blackmore, I. J.; Gibson, V. C.; Long, N. J.;
Marshall, E. L.; White, A. J. P. Dalton Trans. 2006, 3134.
(19) (a) Fleischer, R.; Wunderlich, H.; Braun, M. Eur. J. Org. Chem.
1998, 1063. (b) Braun, M.; Hahn, A.; Engelmann, M.; Fleischer, R.; Frank,
W.; Kryschi, C.; Haremza, S.; Kurschner, K.; Parker, R. Chem.-Eur. J.
2005, 11, 3405. (c) Flores-Lopez, L. Z.; Parra-Hake, M.; Somanathan, R.;
Walsh, P. J. Organometallics 2000, 19, 2153. (d) Davidson, M. G.; Johnson,
A. L.; Jones, M. D.; Lunn, M. D.; Mahon, M. F. Eur. J. Inorg. Chem.
2006, 4449. (e) Johnson, A. L.; Davidson, M. G.; Lunn, M. D.; Mahon,
M. F. Eur. J. Inorg. Chem. 2006, 3088.
1
pounds (as judged by H and 19F NMR). Recrystallization of
crude products afforded only small amounts of crystals, which

Group 4 Metal Complexes of Fluorous Ligands
Organometallics, Vol. 28, No. 2, 2009 611
Scheme 4
Scheme 5
Figure 7. ORTEP view of [TiCl3{ONPh,Ph}{ONHPh,Ph}] (6) (el-
lipsoids drawn at the 50% probability level; all hydrogen atoms
have been omitted for the sake of clarity, except the one on the
protonated imino function). Selected bond lengths (Å) and angles
(deg): Ti(1)-O(41), 1.8298(16); Ti(1)-O(31), 1.8358(16); Ti(1)-
N(11), 2.3020(19); Ti(1)-Cl(2), 2.3394(7); Ti(1)-Cl(1), 2.3608(8);
Ti(1)-Cl(3), 2.3873(7); O(41)-Ti(1)-O(31), 96.80(7); O(41)-
Ti(1)-N(11), 178.84(7); O(31)-Ti(1)-N(11), 82.69(7); O(41)-
Ti(1)-Cl(2), 94.80(5); O(31)-Ti(1)-Cl(2), 92.78(6); N(11)-Ti(1)-
Cl(2), 86.27(5); O(41)-Ti(1)-Cl(1), O(31)-Ti(1)-Cl(1), 92.64(6);
N(11)-Ti(1)-Cl(1), 83.98(5); Cl(2)-Ti(1)-Cl(1), 168.15(3);
O(41)-Ti(1)-Cl(3), 91.71(5); O(31)-Ti(1)-Cl(3), 171.33(6);
N(11)-Ti(1)-Cl(3), 88.77(5); Cl(2)-Ti(1)-Cl(3), 88.13(3);
Cl(1)-Ti(1)-Cl(3), 84.95(3).
computations, are underway to further explore the origin and
mechanism of this decomposition and, on the other hand,
account for the thermal stability of dibenzyl complex 2 (Vide
supra).25,26
This facile decomposition process hampered the isolation
of large amounts of analytically pure dibenzyl complexes 7
and 8. Nonetheless, suitable crystals for X-ray diffraction of
zirconium complexes 7a and 7b and of hafnium complex 8a
could be collected from syntheses performed at low temper-
ature. The solid-state structures of 7a, 7b, and 8a are shown
involve an expectedly longer Ti-OHiPr bond distance (2.134(1)
Å) (as compared to Ti-OiPr, 1.744(1) Å) and a more acute
Ti-O-C bond angle (131.68(9)° vs 151.31(11)°, respectively).
The presence of the 2-propanol molecule also likely accounts
for the reduced trans Ti-O(ligand) bond distance of 1.841(1)
Å, as compared to that of 1.954(1) Å for the Ti-O(ligand) trans
to an isopropoxide group in complex 3a. In zwitterionic complex
6, there is a short Cl(3) · · · H(60)-N(60) contact of 2.439 Å.
Dibenzyl Complexes of Zirconium and Hafnium. Dibenzyl
in Figures 8-10. The three compounds adopt a distorted
-
octahedral geometry with the two {ONR1,R2
}
ligand units
located in the equatorial plane in a cis-N,N/cis-O,O fashion
(20) Repeated attempts under various conditions to obtain
TiCl2{ONR1,R2
} complexes by regular salt metathesis of TiCl4 (or
2
TiCl4(THF)2) with the Li+ (in situ generated), Na+, or K+ (isolated; see
Experimental Section) salts of {ONMe,Ph - and {ONPh,Ph - led to intractable
}
}
complexes of zirconium and hafnium based on monoanionic
mixtures of compounds that could not be separated nor unambiguously
identified. Only in one case could small amounts of crystals be isolated,
-
bidentate ligands {ONR1,R2
}
were prepared by alcoholysis
which proved by X-ray diffraction to be TiCl2{ONPh,Ph}{OOPh}], where
of Zr(CH2Ph)4 and Hf(CH2Ph)4 with 2 equiv of fluorous
alcohol-imines {ONR1,R2}H. These reactions proceed very fast
and selectively, in toluene at low temperature (<-30 °C),
to afford the corresponding M(CH2Ph)2{ONR1,R2}2 complexes
(M ) Zr, 7; M ) Hf, 8), with concomitant release of 2 equiv
of toluene (Scheme 4). However, these compounds subse-
quently decompose at higher temperature (-30 < T (°C) <
20), within minutes to days depending on the nature of the
ligand and the metal, by abstraction of a hydrogen from the
methylene ligand backbone by a benzyl group.12,20,22 This
process is rather selective [main or only decomposition
process observed; see Experimental Section] and eventually
results in the release of a toluene molecule and the formation
of M(CH2Ph){ONR1,R2}{ON-R1,R2} complexes (M ) Zr, 9;
M ) Hf, 10) in which a ligand unit ({ON-R1,R2}) now acts
as an R,ꢀ-unsaturated amido-alkoxy dianionic moiety (Scheme
5). This process differs fundamentally from the one observed
in related Schiff base zirconium alkyls, which decompose
via migration (1,2-migratory insertion or radical) of an alkyl
group to imine.23 In the present case, abstraction of a
hydrogen by a nucleophilic benzyl group can be accounted
for by the high acidity of the methylene group,24 due to its
substitution by electron-withdrawing R-imino and ꢀ-CF3
groups. We cannot, however, rule out other pathways (e.g.,
radical)12 at this stage. More detailed investigations, including
-
{OOPh
}
is the aldolate ligand [(CF3)2C(O)CH2C(dO)Ph]-, i.e., the
decomposition product of the initial ligand. Similarly, all attempts to prepare
dibenzyl complexes of titanium by alcoholysis of Ti(CH2Ph)4 with 2 equiv
of fluorous alcohol-imines {ONR1,R2}H led to intractable mixtures of
compounds. We assume that the latter difficulties reflect the versatile redox
chemistry of Ti, combined with the identified decomposition pathways of
dibenzyl-metal (Zr, Hf) complexes of these new ligands. It is noteworthy
that, to our knowledge, there is no dibenzyl-titanium complex of “regular”
phenoxyimine ligands reported thus far; see refs 8 and 9.
(21) We observed that the reaction of
2 equiv of the aldol
(CF3)2C(OH)CH2C(dO)CH3 ({OOMe}H) (ref 5) with Ti(OiPr)2Cl2 also leads
to the mixed chloride-isopropoxide complex Ti(OiPr)Cl{OOMe}2, as the
main isolable product (see Experimental Section).
(22) For selected examples of decomposition pathways of early transition
metal complexes involving hydrogen abstraction, see: (a) Bernskoetter,
W. H.; Pool, J. A.; Lobkovsky, E.; Chirik, P. J. Organometallics 2006, 25,
1092, and references therein. (b) Schock, L. E.; Brock, C. P.; Marks, T. J.
Organometallics 1987, 6, 232, and references therein. (c) Knight, L. K.;
Piers, W. E.; Fleurat-Lessard, P.; Parvez, M.; McDonald, R. Organometallics
2004, 23, 2087. (d) Pattiasina, J. W.; Hissink, C. E.; de Boer, J. L.; Meetsma,
A.; Teuben, J. H. J. Am. Chem. Soc. 1985, 107, 1158. (e) Skvortsov, G. G.;
Fukin, G. K.; Trifonov, A. A.; Noor, A.; Doring, C.; Kempe, R.
Organometallics 2007, 26, 5770.
(23) (a) Knight, P. D.; Clarkson, G.; Hammond, M. L.; Kimberley, B. S.;
Scott, P. J. Organomet. Chem. 2005, 690, 5125. (b) Knight, P. D.;
O’Shaughnessy, P. N.; Munslow, I. J.; Kimberley, B. S. J. Organomet.
Chem. 2003, 683, 103. (c) Woodman, P. R.; Alcock, N. W.; Munslow,
I. J.; Sanders, C. J.; Scott, P. Dalton Trans. 2000, 3340.
(24) Reaction of {ONMe,Ph}H with 2 equiv of KH readily leads to the
formation of the {ON-Me,Ph}K2, via proton abstraction from the OH and
CHH groups; see Experimental Section.

612 Organometallics, Vol. 28, No. 2, 2009
Marquet et al.
Table 1. Summary of Crystal and Refinement Data for Complexes 1, 3a, 4, 5, 6, 7a, 7b, 7d, 8a, and 11
1
3a
4 · iPrOH
5
6
empirical formula
fw
C14H14Cl2F12N2O2Ti
589.07
C30H34F12N2O4Ti
762.49
C18H25Cl2F6NO3Ti
536.19
C37H31Cl1F12N2O3Ti
862.99
C34H25Cl3F12N2O2Ti.C7H8
967.94
cryst syst
space group
a, Å
b, Å
c, Å
orthorhombic
P212121
11.5983(6)
13.5379(10)
13.592(9)
90
90
90
2134.2(14)
4
1.833
0.770
1168
monoclinic
P21/a
19.910(4)
16.379(4)
20.634(4)
90
95.938(10)
90
6693(2)
triclinic
P1
monoclinic
P21/n
9.1162(9)
12.2176(12)
33.617(3)
90
92.780(3)
90
3739.8(6)
4
monoclinic
P21/c
11.44850(10)
14.96840(10)
24.8484(2)
90
98.7700(10)
90
4208.38(6)
4
j
10.2267(9)
11.4449(11)
14.0137(12)
112.483(4)
106.534(4)
116.075(4)
1140.98(18)
2
R, deg
ꢀ, deg
γ, deg
volume, Å3
Z
8
density, Mg m-3
abs coeff, mm-1
F(000)
1.513
0.360
3120
1.561
0.677
548
1.533
0.400
1752
1.528
0.486
1960
cryst size, mm
θ range, deg
limiting indices
0.05 × 0.06 × 0.16
2.76 to 26.49
-14 e h e 14, -16 e
k e 16, -16 e l e 16
18 411
0.55 × 0.60 × 0.70
2.4 to 27.25
-25 e h e 25, -21 e
k e 16, -26 e l e 26
72 912
0.12 × 0.27 × 0.70
2.26 to 27.43
-13 e h e 13, -14 e
k e 14, -18 e l e 18
22 572
0.18 × 0.35 × 0.55
2.43 to 27.55
-11 e h e 5, -15 e
k e 15, -42 e l e 43
24 893
0.07 × 0.09 × 0.25
2.5 to 25.74
-14 e h e 14, -11 e
k e 19, -31 e l e 32
45 695
refllns collected
reflns unique
[I > 2σ(I)]
data/restraints/
params
4385 (3204)
15 161 (11 450)
5146 (4451)
8531 (7106)
9605 (6430)
4385/0/298
1.002
15 161/0 /883
1.039
5146/0/283
1.043
8531/0/505
1.141
9605/0/613
1.013
goodness-of-fit
on F2
R1 [I > 2σ(I)]
0.0458 (0.0756)
0.1031 (0.1147)
0.0429 (0.0641)
0.0974 (0.1074)
0.0304 (0.0375)
0.0722 (0.0755)
0.0642 (0.079)
0.1346 (0.141)
0.0459 (0.0863)
0.0819 (0.0943)
(all data)
wR2 [I > 2σ(I)]
(all data)
largest diff, e A-3
0.520 and -0.361
0.347 and -0.512
0.368 and -0.425
0.707 and -0.653
0.677 and -0.352
7a
7b
7d
8a
11
empirical formula C38H34F12N2O2Zr · 2(CH2Cl2) C48H38F12N2O2Zr · 1.5(C7H8) C38H24F22N2O2Zr
C38H34F12HfN2O2 · 2(C7H8) C36H14F33N3O3Zr
fw
1039.74
monoclinic
C2/c
1132.23
1049.81
monoclinic
P21/n
1141.43
monoclinic
C2/c
1254.72
monoclinic
P21/a
cryst syst
space group
a, Å
triclinic
j
P1
19.4235(16)
12.3987(13)
18.8797(18)
90
9.12390(8)
11.97510(10)
24.35250(16)
96.3176(4)
96.7064(5)
100.2415(5)
2577.04(7)
2
10.1292(5)
19.7931(9)
19.9920(9)
90
27.555(2)
12.0391(10)
17.9936(14)
90
18.6550(13)
11.5244(10)
22.4943(19)
90
b, Å
c, Å
R, deg
ꢀ, deg
109.048(3)
90
102.105(2)
90
127.787(2)
90
22.4943(19)
90
γ, deg
volume, Å3
4297.8(7)
4
3919.0(3)
4
4717.4(6)
4
4461.7(6)
4
Z
density, Mg m-3
abs coeff, mm-1
F(000)
1.607
1.459
1.779
1.607
1.868
0.595
0.302
0.425
2.302
0.426
2096
1158
2080
2288
2448
cryst size, mm
θ range, deg
limiting indices
0.20 × 0.20 × 0.20
3.29 to 27.4
0.04 × 0.20 × 0.25
2.55 to 27.59
0.25 × 0.30 × 0.30
2.8 to 27.53
0.26 × 0.37 × 0.44
2.73 to 27.52
0.04 × 0.20 × 0.20
2.57 to 27.60
-23 e h e 22, -15 e
k e 11, -14 e l e 24
-11 e h e 11, -15 e
k e 16, -27 e l e 31
-13 e h e 13, -25 e -35 e h e 35, -15 e
-23 e h e 22, -14 e
k e 14, -29 e l e 29
k e 25, -25 e l e 22
38 611
k e 15, -22 e l e 23
35 640
reflns collected
8203
22 178
84 939
reflns unique
[I > 2σ(I)]
4230 (3502)
11 757 (6543)
8952 (7468)
5407 (5298)
10 190 (7995)
data/restraints/
params
4230/0/276
1.055
11 757/0/687
1.041
8952/0/586
5407/0/313
10 190/0/685
1.071
goodness-of-fit
1.041
1.049
on F2
R1 [I > 2σ(I)]
0.0337 (0.0445)
0.0762 (0.0811)
0.0852 (0.1587)
0.2043 (0.2403)
3.035 and -0.917
0.0285 (0.0387)
0.0691 (0.0742)
0.573 and -0.41
0.0154 (0.0159)
0.0386 (0.0389)
0.44 and -0.689
0.0713 (0.0852)
0.2059 (0.2115)
1.894 and -0.884
(all data)
wR2 [I > 2σ(I)]
(all data)
largest diff, e A-3 0.476 and -0.478
and the two benzyl groups at the axial positions, which is a
type D structure (Figure 3). This generates a global C2V-
symmetric environment around the metal center, and a
crystallographic inversion center is actually observed in 7a
and 8a. The Zr-O (2.001(4)-2.016(2) Å) and Zr-N
(2.436(2)-2.483(4) Å) bond distances compare well with
those observed in Zr(IV)-Salen23b,27 (1.962-2.030 and
2.359-2.425 Å, respectively) and Zr(IV) bis(phenoxyimine)
compounds(1.964-2.022and2.316-2.391Å,respectively),8k,23a,28
as well as in the related fluorous dialkoxide-diamino complex
{CH2NMeCH2C(CF3)2O}2Zr(CH2Ph)2.4a The Zr-C bonds in
this latter complex (2.266(1)-2.271(1) Å)4a are just slightly

Group 4 Metal Complexes of Fluorous Ligands
Organometallics, Vol. 28, No. 2, 2009 613
Figure 9. ORTEP view of Zr(CH2Ph)2{ONPh,Ph}2 (7b) (ellipsoids
drawn at the 50% probability level; all hydrogen atoms have been
omitted for the sake of clarity). Selected bond lengths (Å) and angles
(deg): Zr(1)-O(91), 2.001(4); Zr(1)-O(41), 2.006(4); Zr(1)-C(61),
2.297(6); Zr(1)-C(11), 2.305(6); Zr(1)-N(21), 2.462(5); Zr(1)-N(71),
2.483(4);
O(91)-Zr(1)-O(41),
83.31(16);
O(91)-Zr(1)-
C(61), 121.2(2); O(41)-Zr(1)-C(61), 95.4(2); O(91)-Zr(1)-C(11),
93.9(2); O(41)-Zr(1)-C(11), 120.89(19); C(61)-Zr(1)-C(11), 132.9(2);
O(91)-Zr(1)-N(21), 151.67(16); O(41)-Zr(1)-N(21), 75.17(16);
C(61)-Zr(1)-N(21), 79.63(19); C(11)-Zr(1)-N(21), 81.91(19);
O(91)-Zr(1)-N(71), 74.33(16); O(41)-Zr(1)-N(71), 150.80(17);
C(61)-Zr(1)-N(71), 80.90(19); C(11)-Zr(1)-N(71), 79.83(18);
N(21)-Zr(1)-N(71), 131.52(16); C(12)-C(11)-Zr(1), 109.0(4);
C(62)-C(61)-Zr(1), 111.0(4).
Figure 8. ORTEP view of Zr(CH2Ph)2{ONMe,Ph}2 (7a) (ellipsoids
drawn at the 50% probability level; all hydrogen atoms have been
omitted for the sake of clarity; Zr(1) is an inversion center and
atoms obtained by this symmetry operation are named hereafter
with “#”). Selected bond lengths (Å) and angles (deg): Zr(1)-O(21),
2.0163(15); Zr(1)-C(11), 2.310(2); Zr(1)-N(31), 2.4360(18);
O(21)#1-Zr(1)-O(21), 86.83(9); O(21)-Zr(1)-C(11)#1, 91.01(7);
O(21)-Zr(1)-C(11), 123.51(7); C(11)#1-Zr(1)-C(11), 133.81(12);
O(21)#1-Zr(1)-N(31), 149.24(6); O(21)-Zr(1)-N(31), 75.43(6);
C(11)#1-Zr(1)-N(31), 82.37(7); C(11)-Zr(1)-N(31), 78.74(7);
N(31)-Zr(1)-N(31)#1, 130.55(9); C(12)-C(11)-Zr(1), 109.07-
(14).
sharp singlet resonance is observed in the 19F{1H} NMR
spectrum, and the CH2CdN and M-CH2 hydrogens appear as
singlets in the 1H spectrum. These features are consistent with
the C2V-symmetric structures observed in the solid state being
retained in solution.17
shorter than those observed in 7a and 7b (2.297(6)-2.310(2)
Å). Both the benzyl ligands in 7a and 7b have a normal
structure(C(12)-C(11)-Zr(1),109.0(4)-111.0(4)°;Zr(1) · · · C(12),
3.128-3.349 Å), indicative of no significant Zr · · · Ph interac-
tion. Overall, 7a, 7b, and 8a are best described as 16-electron
species, counting the alkoxides as four-electron (σ, π)
donors.4a
The most stable dibenzyl complexes could also be character-
ized in solution by NMR techniques. All 1H and 19F NMR data
of the complexes 7a,b and 8a (as well as 13C NMR for 7a) in
toluene-d8 or CD2Cl2 indicate the presence of a single highly
symmetric species on the NMR time scale. In each case, a single
In the absence of suitable crystals for X-ray diffraction, the
identity and structure of decomposition products 9a-c and 10a,b
were established on the basis of elemental analysis and NMR
spectroscopy. Key data include four quartets in the 19F NMR
1
spectra for the nonequivalent CF3 groups. In the H spectra,
two doublets of an AB spin pattern are observed for both the
diastereotopic CHH-Ph and (CF3)2CCHH units of the “unaf-
fected” ligand backbone, while the R1CdCH of the “affected”
ligand appears as a distinctive singlet at δ 4.51-5.29 ppm
(CD2Cl2, toluene-d8).24 13C NMR data confirm these features.
As for the systems discussed above, reaction of {ONMe,ArF}H
with Zr(CH2Ph)4 at -30 °C afforded Zr(CH2Ph)2{ONMe,ArF
}
2
(7d) (Scheme 6). Crystals of this compound suitable for X-ray
diffraction could be isolated at low temperature. In contrast with
7a, 7b, and 8a, the solid-state structure of 7d features a Zr center
in a distorted octahedral geometry, with approximate (noncrys-
tallographic) C2-symmetry, in which the nitrogen ligand atoms,
oxygen ligand atoms, and benzyl groups are arranged in a
cis,trans,cis fashion (Figure 11), which is a type F structure
(Figure 3). The Zr-N bond distances in 7d (2.523(1)-2.552(1)
(25) To prevent this decomposition pathway, the use of gem-dimethyl-
substituted pro-ligand analogues was attempted. Surprisingly, fluorous
(di)imino-(di)ols such as HOC(CF3)2CMe2C(iPr)dN(iPr) and [HOC-
(CF3)2CMe2C(iPr)dNCH2-]2 were found not to react with M(CH2Ph)4 (M
) Ti, Zr, Hf) in toluene up to 60-80 °C, temperatures at which the latter
precursors start decomposing at a significant rate. Reasons for this absence
of reactivity, while no obvious steric and electronic effects can be accounted
for, remain obscure. To date, such gem-dimethyl-substituted pro-ligands
could be installed only at aluminum centers, under conditions much more
drastic than those used for the parent nonsubstituted pro-ligands; see ref
11.
(26) The reactions of Zr(CH2Ph)4 with 1 equiv of {ONMe,Ph}H or
{ONPh,Ph}H were attempted to potentially access the corresponding
Zr(CH2Ph)2{ON-R1,R2} complexes. However, in both cases, NMR monitor-
ing showed that these reactions led to ca. 1:1 mixtures of Zr(CH2Ph)4 and
Zr(CH2Ph)2{ONR1,R2}2, which further evolve by decomposition of the latter
species into Zr(CH2Ph){ON-R1,R2}{ONR1,R2}. Those observations indicate
that disproportionation of the putative intermediate species [Zr(CH2Ph)3-
{ONR1,R2}] or consecutive reaction of the latter species with {ONPh,Ph}H
(to form in both cases Zr(CH2Ph)2{ONR1,R2}2) is faster than abstraction of
a hydrogen atom from the ligand backbone.
(28) (a) Ivanchev, S. S.; Truno, V. A.; Rybakov, V. B.; Al’bov, D. V.;
Rogozin, D. G. Dokl. Akad. Nauk. SSSR 2005, 404, 57. (b) Strauch, J.;
Warren, T. H.; Erker, G.; Frohlich, R.; Saarenketo, P. Inorg. Chim. Acta
2000, 300, 810. (c) Said, M.; Hughes, D. L.; Bochmann, M. Inorg. Chim.
Acta 2006, 359, 3467. (d) Bott, R. K. J.; Hughes, D. L.; Schormann, M.;
Bochmann, M.; Lancaster, S. J. J. Organomet. Chem. 2005, 665, 135. (e)
Lamberti, M.; Gliubizzi, R.; Mazzeo, M.; Tedesco, C.; Pellecchia, C.
Macromolecules 2004, 37, 276. (f) Marsh, R. E. Acta Crystallogr., Sect.
B: Struct. Sci. 2004, 60, 252. (g) Chen, S.; Zhang, X.; Ma, H.; Lu, Y.;
Zhang, Z.; Li, H.; Lu, Z.; Cui, N.; Hu, Y. J. Organomet. Chem. 2005, 690,
4184. (h) Woodman, P. R.; Munslow, I. J.; Hitchcock, P. B.; Scott, P.
J. Chem. Soc., Dalton Trans. 1999, 4069. (i) Woodman, P.; Hitchcock,
P. B.; Scott, P. Chem. Commun. 1996, 2735.
(27) Clarkson, G. J.; Gibson, V. C.; Goh, P. K. Y.; Hammond, M. L.;
Knight, P. D.; Scott, P.; Smit, T. M.; White, A. J. P.; Williams, D. J. Dalton
Trans. 2006, 5484.

614 Organometallics, Vol. 28, No. 2, 2009
Marquet et al.
Figure 10. ORTEP view of Hf(CH2Ph)2{ONMe,Ph
} (8a) (el-
2
Figure 11. ORTEP view of Zr(CH2Ph)2{ONMe,ArF}2 (7d) (ellipsoids
drawn at the 50% probability level; all hydrogen atoms have been
omitted for the sake of clarity). Selected bond lengths (Å) and angles
(deg): Zr(1)-O(41), 1.9848(12); Zr(1)-O(91), 2.0017(12); Zr(1)-
C(21), 2.2927(18); Zr(1)-C(11), 2.3014(18); Zr(1)-N(31),
2.5229(15); Zr(1)-N(81), 2.5515(14); O(41)-Zr(1)-O(91),
135.40(5); O(41)-Zr(1)-C(21), 103.59(6); O(91)-Zr(1)-C(21),
107.43(6); O(41)-Zr(1)-C(11), 115.12(6); O(91)-Zr(1)-C(11),
99.01(6); C(21)-Zr(1)-C(11), 84.81(7); O(41)-Zr(1)-N(31),
76.45(5); O(91)-Zr(1)-N(31), 80.83(5); C(21)-Zr(1)-N(31),
165.78(6); C(11)-Zr(1)-N(31), 82.42(6); O(41)-Zr(1)-N(81),
82.62(5); O(91)-Zr(1)-N(81), 73.70(5); C(21)-Zr(1)-N(81),
77.79(6); C(11)-Zr(1)-N(81), 157.83(6); N(31)-Zr(1)-N(81),
116.08(5); C(12)-C(11)-Zr(1), 119.36(12).
lipsoids drawn at the 50% probability level; all hydrogen atoms
have been omitted for the sake of clarity; Hf(1) is an inversion
center and atoms obtained by this symmetry operation are named
hereafter with “#”). Selected bond lengths (Å) and angles (deg):
N(11)-Hf(1), 2.3795(12); O(4)-Hf(1), 2.0100(10); C(39)-Hf(1),
2.2951(14); O(4)-Hf(1)-O(4)#1, 84.01(6); O(4)-Hf(1)-C(39),
126.42(5); O(4)#1-Hf(1)-C(39), 89.56(5); C(39)-Hf(1)-C(39)#1,
133.55(8); O(4)-Hf(1)-N(11), 76.33(4); O(4)#1-Hf(1)-N(11),
144.37(4); C(39)-Hf(1)-N(11), 79.08(5); C(39)#1-Hf(1)-N(11),
83.31(5); N(11)-Hf(1)-N(11)#1, 134.35(6); C(36)-C(39)-Hf(1),
113.14(10).
Å) are longer than those in 7a and 7b (2.436(2)-2.483(4) Å),
which likely reflects the trans influence of the benzyl groups.
The latter groups are somewhat more bent than in 7a and 7b
(C(12)-C(11)-Zr(1), 119.36(12)°; C(12) · · · Zr(1), 3.302 Å).
Otherwise, the Zr-O and Zr-C bond distances compare well
in the solid state is not retained in solution but transformed to
a C2V-symmetric structure of type D. This observation indicates
-
that coordination of the {ONR1,R2
}
fragments onto group 4
metals is rather labile, although it most often leads to the
observation of a single species.
1
with those in 7a and 7b. On the other hand, the H and 19F
NMR data for 7d in toluene-d8 solution appear strictly similar
to those for 7a, 7b, and 8a; that is, the type F structure observed
The decomposition pathway of 7d was found to proceed in
a somehow different way than for 7a, 7b, and 8a. When a
toluene solution of 7d was kept at room temperature, complete
decomposition took place within a few hours, leaving colorless
crystals of Zr{ONMe,ArF}2{ON-Me,ArF} (11) (Scheme 6). An X-ray
diffraction study and multinuclear NMR spectroscopy of these
crystals indicated that there is no more benzyl group in this
compound, but three {ONMe,ArF} ligand units including one
({ON-Me,ArF}) that acts as an R,ꢀ-unsaturated amido-alkoxy
dianionic moiety. We can reasonably assume that compound
11 arises from a ligand redistribution in 7d, to generate a
transient intermediate Zr(CH2Ph){ONMe,ArF}3 (not observed by
NMR), which further undergoes rapid abstraction of a hydrogen
from the methylene ligand backbone by the benzyl group
(Scheme 6).
Scheme 6
The X-ray diffraction study of 11 revealed a mononuclear
structure with the Zr center in a slightly distorted octahedral
environment (Figure 12). As a result of the formation of an
amido ligand, the Zr-N bond in the “affected” ligand unit
(2.179(4) Å) is significantly shorter than the two other
Zr-N(imino) bond distances (2.378(5)-2.393(5) Å), while the
Zr-O bond distances are essentially all identical to those
observed in 7a,b,d. The 1H and 19F NMR data for 11 in benzene-
d6 show expectedly two sets of resonances in a 2:1 ratio for the

Group 4 Metal Complexes of Fluorous Ligands
Organometallics, Vol. 28, No. 2, 2009 615
Scheme 7
Repeated attempts under various conditions to obtain such
complexes by regular salt metathesis of ZrCl4 (or ZrCl4(THF)2)
with the Li+ (in situ-generated), Na+, or K+ (isolated; see
-
-
Experimental Section) salt of {ONMe,Ph
} } led
and {ONPh,Ph
to intractable mixtures of compounds that could not be separated
nor unambiguously identified.20 A similar approach from
{ONMe,ArF}Li (in situ generated) or {ONMe,ArF}K (isolated; see
Experimental Section) afforded ZrCl2{ONMe,ArF}2 (12c) in poor
yield, but this compound features so poor solubility in all
common organic solvents that it could be authenticated only
on the basis of microanalysis.
Ethylene Polymerization. The complexes based on bidentate
ligands were briefly investigated in ethylene polymerization.31
Neutral isopropoxide and chloride complexes were activated
with MAO or a combination of [Ph3C][B(C6F5)4] and Al(iBu)3,32
while [Ph3C][B(C6F5)4] was used to generate in situ cationic
benzyl-hafnium species from the relatively stable dibenzyl
complex 8a. The results are summarized in Table 2.
Two general characteristics can be drawn from these pre-
liminary investigations. First, all systems show relatively high
activity in the early stages of the polymerizations but rapidly
deactivate over a 0.1-10 min time period, after which no
ethylene uptake is noticed.33 In fact, in some cases, all of the
polyethylene is formed within the first 10 s of the experiment.
As a consequence, the activity data reported in Table 2, which
were calculated over the whole 10 min time period of the
experiments, barely reflect the real behavior of the catalyst
systems. These apparent activities, which are usually in the range
100-200 kg PE mol-1 h-1, no matter the nature of the metal
and ligand, are of the same order of magnitude as those reported
for related catalysts based on discrete zirconium precursors
having amino-alkoxide or amino-dialkoxide ligands34 and
somewhat lower than those observed for systems based on
sulfur-bridged dialkoxide ligands,30,35 although direct compari-
sons are difficult due to differences in polymerization time and
conditions.
Figure 12. ORTEP view of Zr{ONMe,ArF}2{ON-Me,ArF} (11) (el-
lipsoids drawn at the 50% probability level; all fluorine atoms have
been omitted for the sake of clarity). Selected bond lengths (Å)
and angles (deg): Zr(1)-O(13), 1.999(4); Zr(1)-O(7), 2.011(4);
Zr(1)-O(5), 2.016(4); Zr(1)-N(31), 2.179(4); Zr(1)-N(36),
2.378(5); Zr(1)-N(37), 2.393(5); O(13)-C(55), 1.371(7);
C(49)-C(55), 1.508(8); C(48)-C(49), 1.344(8); N(31)-C(48),
1.416(7); O(13)-Zr(1)-O(7), 166.46(16); O(13)-Zr(1)-O(5),
94.49(16); O(7)-Zr(1)-O(5), 96.73(16); O(13)-Zr(1)-N(31),
81.63(16); O(7)-Zr(1)-N(31), 88.54(16); O(5)-Zr(1)-N(31),
169.58(16); O(13)-Zr(1)-N(36), 92.85(16); O(7)-Zr(1)-N(36),
97.08(15); O(5)-Zr(1)-N(36), 76.76(15); N(31)-Zr(1)-N(36),
93.71(16); O(13)-Zr(1)-N(37), 95.61(16); O(7)-Zr(1)-N(37),
77.84(15); O(5)-Zr(1)-N(37), 85.19(15); N(31)-Zr(1)-N(37),
104.76(16); N(36)-Zr(1)-N(37), 160.60(16).
two “unaffected” and the “affected” ligand units, respectively
(see Experimental Section).
Dichloride Complexes of Zirconium. Efforts have also been
made to access dichlorozirconium complexes, potentially useful
for polymerization catalysis. ZrCl2{ONMe,Ph
}
(12a) and
2
ZrCl2{ONPh,Ph}2 (12b) could be obtained in moderate yields, in
a one-pot procedure, by generating first “Zr(nBu)2Cl2” from
ZrCl4 and nBuLi29 and then adding 2 equiv of the corresponding
pro-ligand {ONR1,R2}H to perform an alkane elimination (Scheme
7).4a 30 Both compounds are moderately soluble in aromatic
,
solvents (toluene, benzene) and sparingly soluble in aliphatic
hydrocarbons (hexanes). NMR data in benzene-d6 of the crude
products recovered following this procedure showed that these
are mixtures of a C2V-symmetric and a C1-symmetric isomer
(12a, 70:30; 12b, 30:70). When heated above 60 °C in benzene-
d6, these (kinetic) mixtures slowly isomerize to yield the C2V-
symmetric (thermodynamic) isomer. Also, C1-12a,b proved to
be much less soluble than C2V-12a,b and could be selectively
isolated by washing the (kinetic) crude mixtures with hot
hexanes (see Experimental Section). C2V-12a,b show the same
NMR features as those discussed above for complexes 3, 7,
and 8. The C1-symmetric isomers of 12a,b are characterized
by four quartets of equal intensity in the 19F NMR spectrum
(these quartets are broadened and two of them overlap in the
case of 12b) and a complete set of resonances for each individual
High initial activities and fast deactivation in ethylene
polymerizations have been also reported with group 4 metal
catalysts supported by sulfur-bridged dialkoxide {OSO}2-
ligands.30 In this case, ligand transfer between group 4 metal
(31) Complexes 1 and 2 were also briefly investigated in polymerization
catalysis, although no valuable performance was expected, considering the
equatorial coordination of the tetradentate ligand and the anticipated absence
of cis vacant sites in the resulting cationic species. As a matter of fact, for
instance, when complex 1 was activated with MAO (1000 equiv, toluene
solution), no polymerization activity was observed (1 atm ethylene, 25 °C).
(32) (a) Chien, J. C. W.; Xu, B. Makromol. Chem. Rapid Commun. 1993,
14, 109. (b) Chien, J. C. W.; Tsai, W. M. Makromol. Chem. Macromol.
Symp. 1993, 66, 141. (c) Chen, Y. X.; Rausch, M. D.; Chien, J. C. W.
Organometallics 1994, 13, 748. (d) Chien, J. C. W.; Rausch, M. D. J. Polym.
Sci. Part A: Polym. Chem. 1994, 32, 2387. (e) Song, F. S.; Cannon, R. D.;
Lancaster, S. J.; Bochmann, M. J. Mol. Catal. A 2004, 218, 21.
(33) In these experiments, polyethylene was recovered in virtually the
same amount as that of ethylene consumed; oligomers (if any) were therefore
negligible.
1
nonaromatic hydrogen in the H NMR spectrum.
(29) (a) Eisch, J. J.; Owuor, F. A.; Shi, X. Organometallics 1999, 18,
1583. (b) Eisch, J. J.; Owuor, F. A.; Otieno, P. O. Organometallics 2001,
20, 4132.
(30) Lavanant, L.; Silvestru, A.; Faucheux, A.; Toupet, L.; Jordan, R. F.;
Carpentier, J.-F. Organometallics 2005, 24, 5604.

616 Organometallics, Vol. 28, No. 2, 2009
Marquet et al.
Table 2. Ethylene Polymerization Dataa
c
d
activator/scavenger
(equiv vs metal)
yield
(g)
activityb
Mw
Tm
c
entry
catalyst precursor
(kg PE mol-1 h-1
)
(103 g mol-1
)
Mw/Mn
(°C)
1
2
3
4
5
6
7
8
9
Ti(OiPr)2{ONMe,Ph}2 (3a)
Ti(OiPr)2{ONPh,Ph}2 (3b)
TiCl2(OiPr){ONMe,Ph} (4)
TiCl(OiPr){ONPh,Ph}2 (5/6)f
ZrCl2{ONMe,Ph}2 (12a)
ZrCl2{ONPh,Ph}2 (12b)
ZrCl2{ONPh,Ph}2 (12b)
ZrCl2{ONMe,ArF}2 (12c)
ZrCl2{ONMe,ArF}2 (12c)
Hf(CH2Ph)2{ONMe,Ph}2 (8a)
MAO (1500)
MAO (1450)
MAO (1100)
MAO (1250)
MAO (1350)
MAO (1200)
[Ph3C][B(C6F5)4] (3)/Al(iBu)3 (40)
MAO (1300)
[Ph3C][B(C6F5)4] (2)/Al(iBu)3 (100)
[Ph3C][B(C6F5)4] (2.2)/Al(iBu)3 (48)
0.429
0.344
0.476
0.460
0.387
0.285
0.009
0.430
0.520
0
195
174
201
222
159
132
4
213
99
0
insolublee
427
135
136
137
136
140
133
133
141
144
2.7
4.7
4.4
8.2
399
375
680
insolublee
insolublee
insolublee
insolublee
10
a Unless otherwise stated, all polymerization experiments were conducted at 50 °C under 7-8 atm of ethylene for 10 min, using 12-32 µmol of
catalyst precursor in 50-60 mL of toluene; the results shown for each entry are representative of at least two reproducible runs. b Average activity
calculated over the whole polymerization time (10 min). c Determined by GPC in 1,2,4-trichlorobenzene at 150 °C. d Determined by DSC (first heating).
e PE could not be solubilized in 1,2,4-trichlorobenzene at 160 °C. f A mixture of complexes 5 and 6 was used.
Scheme 8. Proposed Deactivation Pathway in Ethylene
Polymerizations Catalyzed by M-{ONR1,R2}/Activator Systems
(P stands for the growing polyethylenyl chain)
weight. Many polyethylenes could not be solubilized, calling
for even higher molecular weights. Polyethylenes that could be
analyzed by GPC had broad molecular weight distributions,
although most of them feature monomodal shapes with long
tailing on low33 and high molecular weights (see the Supporting
Information).
Conclusions
The preparation of discrete group 4 metal complexes based
on Schiff base bi- and tetradentate fluorous (di)imino-(di)alkox-
and Al centers was suggested as a possible origin of the catalyst
decay. No direct evidence could be found for such a process in
the present M-{ONR1,R2}/MAO systems.36 The similar catalyst
behavior (decay) observed with quite different activators
(MAO37 vs [Ph3C][B(C6F5)4] with Al(iBu)3; compare entries 8
and 9, Table 2) suggests that another deactivation pathway may
be operative in the present systems. Based on the aforementioned
observation of hydrogen abstraction by a benzyl group in neutral
Zr(CH2Ph)2{ONR1,R2}2 species (Vide supra), we assume that a
similar process may take place in related cationic species
(Scheme 8). Hydrogen abstraction from the ligand backbone
by the growing polyethylenyl chain would eventually result in
the formation of an alkyl-free, inactive species. In this regard,
it is noteworthy that no polymerization at all was noticed when
dibenzyl complex 8a was used as the catalyst precursor (Table
2, entry 10).
-
ide ligands {ONR1,R2
}
and {ONEtNO}2- has been studied.
Diisopropoxide-Ti(IV) and dibenzyl-Zr(IV) and -Hf(IV) com-
plexes have been obtained using straightforward procedures;
the preparation of dichloride-Ti(IV) and -Zr(IV) complexes
based on bidentate ligands proved to be somewhat more difficult.
-
Despite the flexibility of the {ONR1,R2
}
and {ONEtNO}2-
ligands (the bis(trifluoromethyl)alkoxide is not conjugated with
the imino group, in contrast to phenoxy-imine and salen ligands)
and the lability of their coordination onto group 4 metals (two
different stereoisomers of a given compound are sometimes
observed in the solid state and in solution), the formation of a
single stereoisomer is most often observed, usually with
equatorial coordination of the (di)imino-(di)alkoxide functions.
This coordination behavior contrasts with that adopted by related
fluorous diamino-dialkoxide ligands [helicoidal wrapping of the
ligand around the metal center, with both alkoxides located at
apical positions, which is a type B structure].4a This confirms
that imino groups reduce flexibility of the ligand framework.
Another interesting feature revealed in this study is the rapid
decomposition of dibenzyl-Zr(IV) and -Hf(IV) complexes, via
abstraction of a hydrogen from the ligand framework by a benzyl
group. This phenomenon, which is observed only for
M(CH2Ph)2{ONR1,R2}2 complexes based on bidentate ligands,
while Zr(CH2Ph)2{ONEtNO} is stable, provides a reasonable
rational basis for the observed rapid deactivation of putative
[M(alkyl){ONR1,R2}2]+ catalytic species during ethylene poly-
merization.
The second general feature of these polymerizations concerns
the nature of the polymers obtained. All the polyethylenes
produced with the [M-{ONR1,R2}] systems under the conditions
used have a melting temperature in the range 133-144 °C,
indicative of essentially linear long-chain microstructures. The
few polymers that proved to be soluble in 1,2,4-trichlorobenzene
at 160 °C (and thus analyzable by GPC) showed high molecular
(34) Zr(CH2Ph)2[RN{CH2CH2C(O)R′2}2]/MAO (1:500) gave at 50 °C,
5 atm, 136-384 kg PE mol-1 h-1 with Mw ) 143-452,000, Mw/Mn
)
3.4-5.7; see: (a) Shao, P.; Gendron, R. A. L.; Berg, D. J.; Bushnell, G. W.
Organometallics 2000, 19, 509–520. (b) Zr(CH2Ph)2{PyC(CF3)2O}2/MAO
(1:1000) gave at 30 °C, 8 atm, 10 kg PE mol-1 h-1 with Mw ) 375 000,
Mw/Mn ) 28; Zr(CH2Ph)2{PyC(CF3)2O}2/B(C6F5)3 (1:1) gave at 40 °C, 3
atm, 96 kg PE mol-1 h-1 with Mw ) 16 000, Mw/Mn ) 2.6; see ref 3d. (c)
Berg and Kress observed insignificant or no ethylene polymerization activity
with Zr(CH2Ph) [RN{CH2CH2C(O)R′2}2]/B(C6F5) and Zr(CH2Ph) (2,6-
The many possibilities to tune such fluorous (di)alkoxide-
(di)imino ligands5 open avenues for designing and preparing
new series of group 4 metal complexes. Results of ongoing
studies on the coordination chemistry of these original ligands
with oxophilic metal centers, the origin of deactivation pathways,
and the application of these discrete complexes in catalysis will
be reported in due course.
2
3
2
bis{menthoxo}pyridyl)/B(C6F5) 3 combinations, respectively, and attributed
it to the formation of tight ion pairs; see ref 34a and: Gauvin, R. M.; Osborn,
J. A.; Kress, J. Organometallics 2000, 19, 2944.
(35) Eisen and co-workers have reported that the TiCl2[Py{CPh2O) ]/
2
MAO combination exhibits modest ethylene polymerization activity (20
°C, 1 atm); see: Mack, H.; Eisen, M. J. Chem. Soc., Dalton Trans. 1998,
917.
(36) For transfer a phenoxyimino ligand from a Zr to Al center: Makio,
H.; Fujita, T. Macromol. Symp. 2004, 213, 221.
Experimental Section
General Procedures. All experiments were carried out under
purified argon using standard Schlenk techniques or in a glovebox.

Group 4 Metal Complexes of Fluorous Ligands
Organometallics, Vol. 28, No. 2, 2009 617
Hydrocarbon solvents, diethyl ether, and tetrahydrofuran were
distilled from Na/benzophenone; toluene and pentane were distilled
fromNa/Kalloyundernitrogenanddegassedbyfreeze-vacuum-thaw
cycles prior to use. Chlorinated solvents were distilled from calcium
hydride. Deuterated solvents (>99.5% D, Eurisotop) were freshly
distilled from the appropriate drying agent under argon and degassed
prior to use. Pro-ligands {ONEtNO}H2 and {ONR1,R2}H2 were
synthesized according to the reported procedures.5 Zirconium and
(s, 12F). Anal. Calcd for C28H28F12N2O2Zr: C, 45.22; H, 3.79; N,
3.77. Found: C, 45.8; H, 3.8; N, 3.7.
Reaction of {ONMe,Ph}H with Ti(OiPr)4: Synthesis of Ti-
(OiPr)2{ONMe,Ph}2 (3a). A solution of Ti(OiPr)4 (0.240 g, 0.844
mmol) in toluene (ca. 2.5 mL) was added dropwise at -25 °C to
a solution of {ONMe,Ph}H (0.510 g, 1.704 mmol). The mixture was
stirred until it reached room temperature, and volatiles were
removed under vacuum. The solid residue was washed with cold
pentane (ca. 5 mL) and dried under vacuum to give 3a as a white
solid (0.410 g, 63%). Crystals of 3a suitable for X-ray diffraction
studies were obtained by recrystallization from a mixture of toluene
38
hafnium precursors Zr(CH2Ph)4 and Hf(CH2Ph)4 were prepared
following literature procedures. ZrCl4, TiCl4, and Ti(OiPr)4 were
purchased from Strem Chemicals and used as received. [Ph3C]-
[B(C6F5)4] (Boulder), Al(iBu)3 (Aldrich), and MAO (30 wt %
solution in toluene, Albermale; contains ca. 10 wt % of free AlMe3)
were used as received.
1
and hexane. H NMR (500 MHz, benzene-d6, 298 K): δ 1.14 (d,
3JHH ) 6.1, 12H, CH(CH3)2), 1.25 (s, 6H, CH3), 3.10 (s, 4H, CH2),
3
3
4.85 (hept, JHH ) 6.1, 2H, CH(CH3)2), 6.53 (d, JHH ) 7.5, 4H,
o-Ph), 6.94 (t, 3JHH ) 7.2, 2H, p-Ph), 7.03 (t, 3JHH ) 7.6, 4H, m-Ph).
13C{1H} NMR (125 MHz, benzene-d6, 298 K): δ 24.8 (CH3), 37.9
(CH2), 80.2 (CH), 81.5 (hept, 2JCF ) 28.0, C(CF3)2), 122.4 (o-Ph),
NMR spectra were recorded in Teflon-valved NMR tubes on
Bruker AC-200, AC-300, and AM-500 spectrometers at 20 °C
1
unless otherwise stated. H and 13C NMR chemical shifts were
1
determined using residual solvent resonances and are reported versus
124.5 (q, JCF ) 293.0, CF3), 125.1 (p-Ph), 128.3 (m-Ph), 150.1
1
SiMe4. Assignment of signals was made from 2D H-1H COSY
(i-Ph), 175.6 (CdN). 19F{1H} NMR (188 MHz, benzene-d6, 298
K): δ -76.6 (s, 12F). Anal. Calcd for C30H34F12N2O4Ti: C, 47.26;
H, 4.49; N, 3.67. Found: C, 47.2; H, 4.6; N, 3.7.
1
and H-13C HMQC and HMBC NMR experiments. 19F chemical
shifts were determined by external reference to an aqueous solution
of NaBF4. All coupling constants are given in hertz. Elemental
analyses (C, H, N) were performed using a Flash EA1112 CHNS
Thermo Electron apparatus and are the average of two independent
determinations.
Reaction of {ONPh,Ph}H with Ti(OiPr)4: Synthesis of Ti-
(OiPr)2{ONPh,Ph}2 (3b). This compound was prepared following a
similar procedure to the one described above for 3a, starting from
Ti(OiPr)4 (34.9 mg, 122.8 µmol) and {ONPh,Ph}H (88.7 mg, 245.5
µmol). Compound 3b was obtained as a pale yellow solid (70.0
Reaction of TiCl2(OiPr)2 with {ONEtNO}H2: Synthesis of
TiCl2{ONEtNO} (1). A solution of diol {ONEtNO}H2 (100 mg, 0.21
mmol) in toluene (4 mL) was added to a solution of TiCl4 (20.1
mg, 0.106 mmol) and Ti(OiPr)4 (30.1 mg, 0.106 mmol) in toluene
(4 mL) at -30 °C. The reaction mixture was kept at -30 °C
overnight; afterward colorless crystals precipitated. The crystals
were separated from the supernatant, washed with a minimal amount
of toluene, and dried under vacuum to give 1 as colorless crystals
(70 mg, 56%); suitable crystals for X-ray diffraction studies were
1
mg, 64%). H NMR (300 MHz, benzene-d6, 298 K): δ 1.24 (d,
4JHH ) 6.1, 12H, CH(CH3)2), 3.70 (s, 4H, CH2), 5.00 (hept, 3JHH
)
6.1, 2H, CH(CH3)2), 6.71-6.85 (m, 20H, Ph). 1H NMR (300 MHz,
4
CD2Cl2, 298 K): δ 1.06 (d, JHH ) 6.0, 12H, CH(CH3)2), 3.55 (s,
3
4H, CH2), 4.75 (hept, JHH ) 6.0, 2H, CH(CH3)2), 6.67-7.31 (m,
20H, Ph). 13C{1H} NMR (75 MHz, benzene-d6, 298 K): δ 24.9
(CH(CH3)2), 39.2 (CH2), 80.7 (CH(CH3)2), 82.0 (m, C(CF3)2), 124.7
(q, 1JCF ) 292.0, CF3), 124.4, 124.9,126.6, 127.6, 128.0, 128.9 (o-,
m-, p-Ph), 139.7 (i-Ph from NdC-Ph), resonances for the other
two ipso-Ph carbons were not observed, 175.7 (CdN). 19F{1H}
NMR (188 MHz, benzene-d6, 298 K): δ -76.2 (s, 12F). 19F{1H}
NMR (188 MHz, CD2Cl2, 298 K): δ -76.9 (s, 12F). Anal. Calcd
for C40H38F12N2O4Ti: C, 54.19; H, 4.32; N, 3.16. Found: C, 53.9;
H, 4.5; N, 3.4.
1
obtained from this batch. H NMR (500 MHz, CD2Cl2, 298 K): δ
2.37 (s, 6H, CH3), 3.62 (s, 4H, CH2CdN), 4.16 (s, 4H, NCH2).
13C{1H} NMR (125 MHz, CD2Cl2, 298 K): δ 23.6 (CH3), 41.8
(CH2CdN), 46.7 (NCH2), 85.3 (C(CF3)2), 122.2 (q, 1JCF ) 285.3,
CF3), 173.9 (NdC(CH3)). 19F{1H} NMR (188 MHz, CD2Cl2, 298
K): δ -76.2 (s, 12F). Anal. Calcd for C14H14Cl2F12N2O2Ti: C, 28.55;
H, 2.40; N, 4.76. Found: C, 28.9; H, 2.6; N, 4.7.
Reaction of {ONMe,Ph}H with TiCl2(OiPr)2: Synthesis of
TiCl2(OiPr){ONMe,Ph} (4). A solution of Ti(OiPr)4 (24.0 mg, 84.4
µmol) in toluene (1 mL) was added to a solution of TiCl4 (16.0
mg, 84.4 µmol) in toluene (1 mL). The mixture was stirred for 30
min at room temperature and then cooled to -30 °C. A solution of
{ONMe,Ph}H (100 mg, 334 µmol, 2 equiv vs Ti) in hexane (2 mL),
precooled at -30 °C, was then added dropwise to the previous
solution. A precipitate immediately formed (65 mg, 37%). The solid
was separated from solution by cannula, dried under vacuum, and
recrystallized from dichloromethane at -30 °C to yield colorless
crystals of 4 · iPrOH, which proved suitable for X-ray diffraction
studies (30 mg, 17%). Anal. Calcd for C18H25Cl2F6NO3Ti: C, 40.32;
H, 4.70; N, 2.61. Found: C, 40.1; H, 4.6; N, 2.8. These crystals
lose the coordinated 2-propanol molecule upon prolonged drying
Reaction of {ONEtNO}H2 with Zr(CH2Ph)4: Synthesis of
Zr(CH2Ph)2{ONEtNO} (2). NMR-scale synthesis: A Teflon-valved
NMR tube was charged with diol {ONEtNO}H2 (25.7 mg, 54.4
µmol) and Zr(CH2Ph)4 (24.8 mg, 54.4 µmol), and dry toluene-d8
(ca. 0.5 mL) was vacuum-transferred in at -78 °C. The tube was
kept for 3-4 h at -30 °C, and NMR was recorded at room
temperature, revealing the formation of 2 in 95% yield, as
1
determined by H NMR spectroscopy. Preparative synthesis: A
solution of Zr(CH2Ph)4 (0.41 g, 0.89 mmol) in toluene (3 mL)
precooled at-30 °C was added under vigorous stirring to a solution
of {ONEtNO}H2 (0.42 g, 0.86 mmol) in toluene (4 mL) at -30 °C.
The reaction mixture was kept at -30 °C overnight, after which 2
precipitated as a yellow crystalline solid, which was separated and
1
dried in Vacuo (0.25 g, 38%). H NMR (500 MHz, CD2Cl2, 298
1
under vacuum to give 4. H NMR (300 MHz, CD2Cl2, 298 K): δ
K): δ 2.09 (s, 4H, CH2Ph), 2.12 (s, 6H, CH3), 2.85 (s, 4H,
1.15 (d, 3JHH ) 5.8, 6H, OCH(CH3)2), 1.98 (s, 3H, CH3), 3.21 (br
s, 2H, CH2), 4.54 (br m, 1H, OCH(CH3)2), 6.94 (br s, 2H, o-Ph),
3
CH2CdN), 3.62 (s, 4H, NCH2), 6.64 (d, JHH ) 7.5, 4H, o-Ph),
3
3
6.71 (t, JHH ) 7.5, 2H, p-Ph), 7.00 (m, JHH ) 7.5, 4H, m-Ph).
13C{1H} NMR (125 MHz, CD2Cl2, 298 K): δ 21.1 (CH2Ph), 24.0
(CH3), 40.6 (CH2-CdN), 51.3 (NCH2), 79.5 (C(CF3)2), 119.9 (p-
Ph), 123.8 (CF3), 125.5 (o-Ph), 127.6 (m-Ph), 151.1 (i-Ph), 177.5
(NdC(CH3)). 19F{1H} NMR (188 MHz, CD2Cl2, 298 K): δ -76.9
3
3
7.24 (t, JHH ) 7.6, 1H, p-Ph), 7.40 (t, JHH ) 7.6, 2H, m-Ph).
13C{1H} NMR (75 MHz, CD2Cl2, 298 K): δ 24.0 (CH(CH3)2), 24.2
(CH3), 39.6 (CH2), 84.3 (CH(CH3)2), 121.7 (o-Ph), 125.9 (p-Ph),
129.0 (m-Ph), 147.7 (i-Ph), 174.6 (CdN). 19F{1H} NMR (188 MHz,
CD2Cl2, 298 K): δ -77.6 (br s, 6F).
Reaction of {ONPh,Ph}H with TiCl2(OiPr)2: Isolation of
TiCl(OiPr){ONPh,Ph}2 (5) and [TiCl3{ONPh,Ph}{ONHPh,Ph}] (6). A
solution of Ti(OiPr)4 (10.0 mg, 35.2 µmol) in toluene (1 mL) was
added to a solution of TiCl4 (7.0 mg, 36.9 µmol) in toluene (1
mL). The mixture was stirred for 4 h at room temperature and then
(37) Similar catalytic behavior was observed upon using commercial
MAO and DMAO (dried MAO from which most of the AlMe3 has been
removed).
(38) Zucchini, U.; Albizzati, E.; Giannini, U. J. Organomet. Chem. 1971,
26, 357.

618 Organometallics, Vol. 28, No. 2, 2009
Marquet et al.
cooled to -30 °C. A solution of {ONPh,Ph}H (50 mg, 138 µmol) in
hexane (4 mL), precooled at -30 °C, was then added dropwise to
the previous solution. The reaction mixture was gently warmed to
room temperature overnight, after which time period colorless
crystals appeared that proved suitable for X-ray diffraction studies
(8.0 mg); the latter studies revealed that these crystals are a mixture
room temperature. 1H NMR spectroscopy showed quantitative and
selective conversion of the reagents into 7b. Repeated NMR data
acquisitions after a short time period showed the appearance of
resonances characteristic for the decomposition compound 9b and
toluene. Complete and selective decomposition of 7b into 9b was
observed after 10 min. Preparation of X-ray suitable single crystals
of 7b: In the glovebox, a solution of {ONPh,Ph}H (40.0 mg, 110
µmol) in toluene (ca. 1 mL) precooled at -30 °C was added to a
solution of Zr(CH2Ph)4 (25.0 mg, 54.9 µmol) in toluene (ca. 1 mL)
at -30 °C. The mixture was kept standing in the freezer at -30
°C until crystals of 7b appeared on the walls of the vial and were
1
of 5 and 6. The H and 19F NMR spectra of this mixture showed
many resonances that could not be assigned.
Reaction of (CF3)2C(OH)CH2C(dO)CH3 ({OOMe}H) with
TiCl2(OiPr)2: Synthesis of TiCl(OiPr){OOMe}2. A solution of
Ti(OiPr)4 (145 mg, 510 µmol) in toluene (3 mL) was added to a
solution of TiCl4 (97.0 mg, 511 µmol) in toluene (3 mL). The
mixture was stirred for 30 min at room temperature and then cooled
to -30 °C. A solution of (CF3)2C(OH)CH2C(dO)CH3 ({OOMe}H)
(445 mg, 1.99 mmol, 2 equiv vs Ti) in toluene (2 mL), precooled
at -30 °C, was then added dropwise to the previous solution. The
reaction mixture was gently warmed to room temperature overnight,
volatiles were removed under vacuum, and the solid residue was
washed with pentane (2 × 3 mL) and finally dried under vacuum
to give TiCl(OiPr){OOMe}2 as a white powder (280 mg, 48%). 1H
collected for X-ray data diffraction studies. Zr(CH2Ph)2{ONPh,Ph
}
2
(7b): 1H NMR (300 MHz, CD2Cl2, 298 K): δ 2.05 (br s, 8H, CH2),
6.75-7.26 (m, 30H, Ph). 19F{1H} NMR (188 MHz, CD2Cl2, 298
K): δ -76.5 (s, 12F). 19F{1H} NMR (188 MHz, toluene-d8, 298
K): δ -80.9 (s, 12F). 13C NMR and microanalysis of this compound
were not possible due to its slow decomposition in solution as well
as in the solid state. Zr(CH2Ph){ONPh,Ph}{ON-Ph,Ph} (9b): 1H NMR
(300 MHz, CD2Cl2, 298 K): δ 1.91 (d, 2JHH ) 11.8, 1H, CHH-Ph),
2
2
2.21 (d, JHH ) 11.8, 1H, CHH-Ph), 3.22 (d, JHH ) 17.3, 1H,
2
3
CHH), 3.32 (d, JHH ) 17.3, 1H, CHH), 5.09 (s, 1H, CH),
NMR (300 MHz, benzene-d6, 298 K): δ 1.29 (d, JHH ) 6.0, 6H,
6.63-7.26 (m, 25H, Ph). 1H NMR (500 MHz, toluene-d8, 298 K):
OCH(CH3)2), 1.49 (s, 6H, 2 CH3), 2.75 (d, 2JHH ) 16.0, 2H, CHH),
2
2
2
3
δ 2.08 (d, JHH ) 12.0, 1H, CHHPh), 2.33 (d, JHH ) 12.0, 1H,
CHHPh), 2.98 (s, 2H, CH2), 5.36 (s, 1H, CH), 6.71-7.13 (m, 25H,
2.99 (br d, JHH ) 16.0, 2H, CHH), 5.08 (hept, JHH ) 6.0, 1H,
OCH(CH3)2). 13C{1H} NMR (75 MHz, benzene-d6, 298 K): δ 23.6
(CH(CH3)2), 31.5 (CH3), 39.8 (CH2), 87.6 (CH(CH3)2). 19F{1H}
NMR (188 MHz, benzene-d6, 298 K): δ -77.8 (br m, 6F), -77.5
(br s, 6F). Anal. Calcd for C6H5Cl2F6O2Ti: C, 21.08; H, 1.47. Found:
C, 21.5; H, 1.8.
Ph). 19F{1H} NMR (188 MHz, CD2Cl2, 298 K): δ -79.2 (q, JFF
4
) 9.2, 3F), -78.5 (q, 4JFF ) 9.2, 3F), -78.3 (q, 4JFF ) 10.3, 3F),
-76.9 (q, JFF ) 10.3, 3F). 19F{1H} NMR (188 MHz, toluene-d8,
4
1
298 K): δ -83.8 (q, JFF ) 9.4, 3F), -83.0 (2q overlapping, 6F),
4
Reaction of {ONMe,Ph}H with Zr(CH2Ph)4: Synthesis of
-81.5 (q, JFF ) 9.4, 3F). Anal. Calcd for C41H30F12N2O2Zr: C,
Zr(CH2Ph)2{ONMe,Ph}2 (7a) and Zr(CH2Ph){ONMe,Ph}{ON-Me,Ph
}
54.60; H, 3.35; N, 3.11. Found: C, 54.3; H, 3.4; N, 3.0.
(9a). A solution of {ONMe,Ph}H (200 mg, 668 µmol) in toluene
(ca. 1 mL) precooled at -30 °C was added to a solution of
Zr(CH2Ph)4 (152 mg, 334 µmol) in toluene at -30 °C. The mixture
was kept standing in the freezer at -30 °C until some precipitate
appeared. The supernatant solution was removed by pipet, and the
solid residue was dried under vacuum to give 7a as a yellow powder
(182 mg, 29%). Suitable crystals for X-ray diffraction were grown
NMR-Scale Reaction of {ONPh,Bn}H with Zr(CH2Ph)4: Syn-
thesis of Zr(CH2Ph){ONPh,Bn}{ON-Ph,Bn} (9c). A Teflon-valved
NMR tube was charged with {ONPh,Bn}H (20.0 mg, 53.3 µmol)
and Zr(CH2Ph)4 (12.1 mg, 26.5 µmol), and CD2Cl2 (ca. 0.5 mL)
was vacuum-transferred in at -78 °C. The tube was kept at low
temperature until NMR was recorded at room temperature, which
showed complete conversion of the reagents to 9c (resonances for
1
1
from CD2Cl2 at -10 °C. H NMR (500 MHz, CD2Cl2, 298 K): δ
7c were not observed). H NMR (300 MHz, CD2Cl2, 298 K): δ
2
2
1.81 (s, 6H, CH3), 1.83 (s, 4H, CH2), 1.92 (br s, 4H, CH2Ph),
6.73-7.32 (m, 20H, Ph). 19F{1H} NMR (188 MHz, CD2Cl2, 298
K): δ -77.0 (s, 12F). 13C{1H} NMR (125 MHz, CD2Cl2, 298 K):
δ 26.5 (CH3), 36.8 (CH2), 69.1 (CH2-Ph), 178.6 (CdN); resonances
for aromatic carbons were not assigned due to the presence of
decomposition products (essentially 9a, Vide infra) that formed
during data acquisition; resonances for quaternary carbons and CF3
were not observed. Microanalysis of this compound was not possible
due to its slow decomposition at room temperature in the solid state.
1.71 (d, JHH ) 10.8, 1H, Zr-CHHPh), 2.05 (d, JHH ) 10.8, 1H,
2
2
Zr-CHHPh), 3.10 (d, JHH ) 17.4, 1H, CHHCdN), 3.25 (d, JHH
) 17.4, 1H, CHHCdN), 4.36 (d, 2JHH ) 17.0, 1H, NCHHPh), 4.60
(d, 2JHH ) 17.0, 1H, NCHHPh), 4.60 (s, 1H, CH), 4.78 (d, 2JHH
)
2
13.8, 1H, NCHHPh), 5.17 (d, JHH ) 13.8, 1H, NCHHPh),
6.81-7.45 (m, 25H, Ph). 19F{1H} NMR (188 MHz, CD2Cl2, 298
K): δ -78.4 (q, 4JFF ) 9.4, 3F), -77.9 (2q overlapping, 6F), -77.2
(q, 1JFF ) 9.4, 3F). Anal. Calcd for C43H34F12N2O2Zr: C, 55.54; H,
3.69; N, 3.01. Found: C, 55.1; H, 3.9; N, 2.8.
Reaction of {ONMe,Ph}H with Hf(CH2Ph)4: Synthesis of
Decomposition of 7a in toluene solution proceeded slowly at
room temperature and was completed after one week, yielding 9a
Hf(CH2Ph)2{ONMe,Ph}2 (8a) and Hf(CH2Ph){ONMe,Ph}{ON-Me,Ph
}
1
as the major product (68% according to H NMR). 1H NMR (500
(10a). A Schlenk flask was charged with {ONMe,Ph}H (101.5 mg,
0.34 mmol) and Hf(CH2Ph)4 (93.0 mg, 0.17 mmol), and toluene
(ca. 5 mL) was vacuum-transferred in at -78 °C. The reaction
mixture was stirred at room temperature for 1 h, over which time
period some precipitate formed. The supernatant solution was
removed by cannula, and the solid residue was dried under the
vacuum, giving 8a as an off-white solid (85 mg, 52%). The NMR
tube was charged with this solid, and toluene-d8 was vacuum-
transferred in (ca. 0.5 mL). Crystals of 8a suitable for X-ray
diffraction studies were obtained by recrystallization from toluene.
1H NMR (200 MHz, toluene-d8, 298 K): δ 1.14 (s, 6H, CH3), 1.43
(s, 4H, CH2), 1.84 (br s, 4H, CH2Ph), 6.48-7.10 (m, 20H, Ph).
19F{1H} NMR (188 MHz, toluene-d8, 298 K): δ -76.5 (s, 12F).
Anal. Calcd for C38H34F12HfN2O2: C, 47.68; H, 3.58; N, 2.93.
Found: C, 47.3; H, 3.4; N, 2.7. When a toluene-d8 solution of 8a
was kept for 10 days at room temperature, the complex decomposed
to form mainly 10a (ca. 65%, as determined by 1H NMR), as well
as other minor (ca. 35%) unidentified secondary products. 1H NMR
MHz, CD2Cl2, 298 K): δ (ppm) 1.80 (s, 3H, CH3), 1.84 (s, 3H,
CH3), 2.00 (d, 2JHH )11.7, 1H, CHH-Ph), 2.17 (d, 2JHH )11.7, 1H,
2
2
CHH-Ph), 2.66 (d, JHH ) 16.2, 1H, CHH), 2.82 (d, JHH ) 16.2,
1H, CHH), 4.56 (s, 1H, CH), from 6.53 to 7.45 (m, 15H, Ph).
19F{1H} NMR (188 MHz, CD2Cl2, 298 K): δ (ppm) -79.3 (br q,
3F), -78.9 (br q, 3F), -77.7 (br q, 3F), -77.5 (br q, 3F). 13C{1H}
NMR (125 MHz, CD2Cl2, 298 K): δ 25.2 (CH3), 25.9 (CH3), 39.4
(CH2), 66.6 (CH2Ph), 94.4 (CH), 181.0 (CdN); for the same reasons
as for 7a, other resonances for 9a could not be attributed or were
not observed.
Reaction of {ONPh,Ph}H with Zr(CH2Ph)4: Synthesis of
Zr(CH2Ph)2{ONPh,Ph}2 (7b) and Zr(CH2Ph){ONPh,Ph}{ON-Ph,Ph
}
(9b). NMR-scale reaction. In the glovebox, a Teflon-valved NMR
tube was charged with pro-ligand {ONPh,Ph}H (21.0 mg, 58.0 µmol)
and Zr(CH2Ph)4 (13.0 mg, 28.5 µmol). CD2Cl2 (ca. 0.5 mL) was
vacuum-transferred in at low temperature, and the tube was kept
at -20 °C for a few minutes until NMR was run immediately at

Group 4 Metal Complexes of Fluorous Ligands
Organometallics, Vol. 28, No. 2, 2009 619
2
(200 MHz, CD2Cl2, 298 K): δ 1.48 (s, 3H, CH3), 1.80 (d, JHH
)
38.00; H, 2.66; N, 3.69. Found: C, 38.1; H, 2.8; N, 3.6. NMR
revealed that this product is a 70:30 mixture of two isomers: the
major one is C2V-symmetric and the minor one is C1-symmetric.
Heating of this mixture at 70 °C for 48 h in benzene-d6 led to a
77:23 mixture of C2V- and C1-12b, as monitored by 1H NMR. When
this mixture of isomers was extracted in hot hexanes, the insoluble
powder left after filtration was shown to be exclusively the C1-
9.4, 1H, CHHPh), 1.98 (s, 3H, CH ), 2.00 (d, JHH ) 9.4, 1H, CHHPh),
2.67 (d, 2JHH ) 16.5, 1H, CHH), 2.87 (d, 2JHH ) 16.5, 1H, CHH),
4.51 (s, 1H, CH), 6.57-7.48 (m, 15H, Ph). 19F{1H} NMR (188
MHz, CD2Cl2, 298 K): δ -79.6 (q, 4JFF ) 9.4, 3F), -79.1 (q, 4JFF
) 9.4, 3F), -78.1 (q, JFF ) 9.4, 3F), -77.6 (q, JFF ) 9.4, 3F).
NMR-Scale Reaction of {ONPh,Ph}H with Hf(CH2Ph)4: Gen-
2
3
4
4
1
eration of Hf(CH2Ph)2{ONPh,Ph
}
(8b) and Hf(CH2Ph)-
symmetric isomer. C2V-12a: H NMR (500 MHz, benzene-d6, 298
2
K): δ (ppm) 1.09 (s, 6H, CH3), 3.03 (s, 4H, CH2), 6.82 (d, 3JHH
)
{ON-Ph,Ph}{ON-Ph,Ph} (10b). A Teflon-valved NMR tube was
charged with {ONPh,Ph}H (30.0 mg, 83.0 µmol) and Hf(CH2Ph)4
(22.5 mg, 41.4 µmol), and toluene-d8 (ca. 0.5 mL) was vacuum-
transferred in at -78 °C. The tube was kept at -78 °C until NMR
7.6 Hz, 4H, o-Ph), 6.95 (t, 3JHH ) 7.6 Hz, 2H, p-Ph), 7.07 (t, 3JHH
) 7.6 Hz, 4H, m-Ph). 13C{1H} NMR (125 MHz, benzene-d6, 298
K): δ 25.1 (CH3), 40.0 (CH2), 81 (m, C(CF3)2), 123.1 (o-Ph), 123.6
1
1
(q, JCF ) 303.7, CF3), 127.1 (p-Ph), 129.4 (m-Ph), 146.6 (i-Ph),
spectroscopy was recorded at room temperature. H NMR spec-
troscopy recorded after 1 min at this temperature revealed that all
reagents were consumed and that transient 8b quantitatively
183.2 (CdN). 19F{1H} NMR (188 MHz, benzene-d6, 298 K): δ
-76.5 (s, 12F). C1-12a: 1H NMR (500 MHz, benzene-d6, 298 K):
2
1
δ 1.15 (s, 3H, CH3), 1.53 (s, 3H, CH3), 2.70 (d, JHH ) 15.0, 1H,
decomposed into 10b and toluene. H NMR (500 MHz, benzene-
CHH), 3.17 (d, 2JHH ) 15.8, 1H, CHH), 3.55 (d, 2JHH ) 15.0, 1H,
2
2
d6, 298 K): δ 2.19 (d, JHH ) 12.9, 1H, CHHPh), 2.39 (d, JHH
)
2
3
CHH), 4.27 (d, JHH ) 15.8, 1H, CHH), 5.37 (br d, JHH ) 7.2,
12.9, 1H, CHHPh), 3.04 (s, 2H, CH2), 5.46 (s, 1H, CH), 6.78-7.27
3
1
1H, o-Ph), 6.63-7.25 (m, 8H, Ph), 8.19 (br d, JHH ) 7.5, 1H,
(m, 25H, Ph). H NMR (200 MHz, toluene-d8, 298 K): δ 2.02 (d,
o-Ph). 19F{1H} NMR (188 MHz, benzene-d6, 298 K): δ -79.1 (br
2JHH ) 12.9, 1H, CHHPh), 2.22 (d, JHH ) 12.9, 1H, CHHPh),
2
1
s, 3F), -77.8 (br s, 3F), -75.5 (q, JFF ) 10.3, 3F), -75.1 (br s,
2.94 (s, 2H, CH2), 5.29 (s, 1H, CH), 6.71-7.13 (m, 25H, Ph).
3F). 13C{1H} NMR (125 MHz, benzene-d6, 298 K): δ 25.6 (CH3),
26.6 (CH3), 39.0 (CH2), 40.3 (CH2), 80.5 (m, C(CF3)2), 81.4 (m,
C(CF3)2), 120.7 (o-Ph), 123.0 (o-Ph), 124.7 (q, 1JCF ) 297.1, CF3),
1
19F{1H} NMR (188 MHz, toluene-d8, 298 K): δ -79.0 (q, JFF
)
9.4, 3F), -78.2 (2 q overl., 1JFF ) 9.4, 6F), -76.5 (q, 1JFF ) 9.4,
3F). 19F{1H} NMR (188 MHz, benzene-d6, 298 K): δ -78.9 (q,
1
4JFF ) 9.4, 3F), -78.2 (q, JFF ) 9.4, 3F), -78.1 (q, JFF ) 9.4,
4
4
124.8 (q, JCF ) 312.4, CF3), 125.4 (o-Ph), 125.9 (p-Ph), 126.0
3F), -76.5 (q,4JFF ) 9.4, 3F).
(o-Ph), 126.4 (p-Ph), 129.0 (m-Ph), 129.3 (2 m-Ph), 130.0 (m-Ph),
148.4 (i-Ph), 149.5 (i-Ph), 177.4 (C)N), 182.8 (CdN).
Reaction of {ONMe,ArF}H with Zr(CH2Ph)4: Synthesis of
Zr(CH2Ph)2{ONMe,ArF}2 (7d) and Zr{ONMe,ArF}2{ON-Me,ArF} (11).
A Teflon-valved NMR tube was charged with {ONMe,ArF}H (68.3
mg, 175.5 µmol) and Zr(CH2Ph)4 (40.0 mg, 87.8 µmol), and
toluene-d8 (ca. 0.5 mL) was vacuum-transferred in at -78 °C. The
tube was kept for 3-4 h at -30 °C, and afterward NMR
spectroscopy was recorded at room temperature. The formation of
7d proceeded in ca. 80% yield according to 1H NMR. Green-yellow
crystals of 7d suitable for X-ray diffraction studies were obtained
by cooling the solution at -30 °C for 20 h (10 mg, 11% yield). 1H
NMR (500 MHz, toluene-d8, 298 K): δ 1.19 (s, 6H, CH3), 2.38 (s,
4H, CH2Ph), 2.74 (s, 4H, CH2), 6.86-7.09 (m, 10H, Ph). 19F{1H}
NMR (188 MHz, toluene-d8, 298 K): δ -167.2 (m, 4F, m-F),
-162.7 (t, 2F, p-F), -151.9 (br s, 4F, o-F), -82.3 (s, 12F, CF3).
Due to the instability of 7d at room temperature in toluene solution,
13C NMR and HETCOR spectra were not recorded. The toluene
solution of 7d was kept in the glovebox at ambient temperature
for one day, after which time period pale-yellow crystals of 11
suitable for X-ray diffraction studies were recovered (36.3 mg, 33%
Synthesis of ZrCl2{ONPh,Ph
} (12b). This compound was
2
prepared following a procedure similar to the one described above
for 12a, starting from ZrCl4 (161 mg, 0.691 mmol) and {ONPh,Ph}H
(500 mg, 1.384 mmol). Compound 12b was obtained as a white
powder (170 mg, 28%), which proved to be a 30:70 mixture of a
C2V-symmetric and a C1-symmetric isomer. Heating of this mixture
at 70 °C for 2.5 days in benzene-d6 led to the complete and selective
1
transformation to C2V-12b, as monitored by H NMR. Extraction
of the C2V/C1-mixture with hot hexanes left a residue that proved
to be analytically pure C1-12b. C2V-12b: 1H NMR (300 MHz,
benzene-d6, 298 K): δ 3.66 (s, 4H, CH2), 6.46-7.42 (m, 20H, Ph).
19F{1H} NMR (188 MHz, benzene-d6, 298 K): δ -76.5 (s, 12F).
1
2
C1-12b: H NMR (500 MHz, benzene-d6, 298 K): δ 3.42 (d, JHH
) 15.5, 1H, CHH), 3.94 (d, 2JHH ) 17.0, 1H, CHH), 4.32 (d, 2JHH
) 15.5, 1H, CHH), 5.01 (d, JHH ) 17.0, 1H, CHH), 5.44 (br d,
2
1H, o-Ph), 6.3 (br t, 1H, m-Ph), 6.54 (m, 1H, Ph), 6.60-6.68 (m,
10H, Ph), 6.84 (t, 3JHH ) 7.9, 2H, Ph), 7.21 (br t, 1H, m-Ph), 7.46
(m, 3H, Ph), 8.77 (br d, 1H, o-Ph). 19F{1H} NMR (188 MHz,
benzene-d6, 298 K): δ (ppm) -78.8 (br m, 3F), -77.7 (br m, 3F),
-74.8 (2 m overl., 6F). Anal. Calcd for C34H24Cl2F12N2O2Zr: C,
46.26; H, 2.74; N, 3.17. Found: C, 46.5; H, 2.9; N, 3.3.
1
yield). H NMR (500 MHz, benzene-d6, 298 K): δ 1.02 (s, 3H,
CH3), 1.04 (s, 6H, CH3), 3.16 (s, 4H, CH2), 4.82 (s, 1H, CH).
13C{1H} NMR (125 MHz, benzene-d6, 298 K): δ 22.3 (CH3), 26.0
(CH3), 39.8 (CH2), 81.3 (C(CF3)2), 99.3 (CH), 150.0
(CHdC(CH3)N), 193.3 (CdN); the remaining resonances were not
observed by HMQC and HMBC methods. 19F{1H} NMR (188
MHz, benzene-d6, 298 K): δ -165.5 (m, 2F, p-F), -161.9 (m, 5F,
m- and p-F), -155.9 (m, 2F, m-F), -149.2--146.7 (br m, 6F,
o-F), -78.0 (s, 6F, CF3), -77.5 (s, 12F, CF3). Anal. Calcd for
C36H14F33N3O3Zr: C, 34.46; H, 1.12; N, 3.35. Found: C, 35.10; H,
1.50; N, 3.3.
Synthesis of ZrCl2{ONMe,ArF
}
(12c). To a solution of
2
{ONMe,ArF}H (0.70 g, 1.80 mmol) in Et2O (30 mL) kept at -78 °C
was added dropwise nBuLi (0.72 mL of a 2.5 M solution in hexanes,
1.80 mmol). The reaction mixture was stirred for 3 h at -78 °C
and then allowed to warm to room temperature over 1 h. Volatiles
were removed under vacuum, and solid ZrCl4 (0.21 g, 0.90 mmol)
was added to the mixture in the glovebox. Et2O (30 mL) was
vacuum-transferred to the reaction mixture, and the latter was stirred
for 12 h at room temperature. Volatiles were removed under
vacuum, and dichloromethane (30 mL) was vacuum-transferred onto
the solid residue. The resulting solution was filtered off, the pale
pink solution was concentrated to ca. 5-7 mL, hexane (5 mL) was
added, and the solution was left at -30 °C. After 10 h, a pink
microcrystalline solid precipitated out. This was separated and dried
under vacuum to give 12c as a white solid (0.100 g, 12%). This
compound featured extremely poor solubility in all common
solvents, which hampered characterization by NMR. Anal. Calcd
for C24H10Cl2F22N2O2Zr: C, 30.72; H, 1.07; N, 2.99. Found: C, 30.5;
H, 1.0; N, 3.1.
Synthesis of ZrCl2{ONMe,Ph}2 (12a). A slurry of ZrCl4 (192 mg,
0.824 mmol) in toluene (30 mL) was cooled at -78 °C, and nBuLi
(0.66 mL of a 2.5 M solution in hexanes, 1.65 mmol, 2 equiv) was
added dropwise. After 25 min of stirring at room temperature, the
light brown solution was cooled at -50 °C, and a solution of
{ONMe,Ph}H (496 mg, 1.66 mmol) in toluene (10 mL) was added
dropwise. The reaction mixture was stirred at room temperature
overnight and then filtered. The clear filtrate was concentrated under
vacuum, and the resulting sticky residue was washed with dry
hexane (ca. 5 mL) and dried under vacuum to give 12a as a white
powder (245 mg, 39%). Anal. Calcd for C24H20Cl2F12N2O2Zr: C,

620 Organometallics, Vol. 28, No. 2, 2009
Marquet et al.
Reaction of {ONR1,R2}H with Na: Synthesis of {ONR1,R2}Na.
{ONPh,Ph}Na: In a typical experiment, in the glovebox, a Schlenk
flask was charged with {ONPh,Ph}H (514 mg, 1.42 mmol) and Na
powder (32.7 mg, 1.42 mmol). Dry THF (ca. 10 mL) was vacuum-
transferred in at -78 °C, and the mixture was stirred overnight at
room temperature. Volatiles were removed under vacuum, and the
solid residue was washed with hexane (ca. 5 mL) and dried under
vacuum to give {ONPh,Ph}Na as a white powder (355 mg, 65%).
1H NMR (200 MHz, benzene-d6, 298 K): δ 3.21 (s, 2H, CH2),
6.78-7.05 (m, 10H, Ph). 19F{1H} NMR (188 MHz, benzene-d6,
298 K): δ -78.5 (s, 6F, CF3). Anal. Calcd for C17H12F6NNaO: C,
53.27; H, 3.16; N, 3.65. Found: C, 53.4; H, 3.3; N, 3.6. Synthesis
of {ONMe,Ph}Na: This compound was prepared following a similar
procedure to the one described above for {ONPh,Ph}Na, starting from
{ONMe,Ph}H (500 mg, 1.67 mmol) and Na powder (38.5 mg, 1.67
mmol). {ONMe,Ph}Na was obtained as a white powder (370 mg,
and forced to ride on the attached atom. The hydrogen atom
contributions were calculated but not refined. All non-hydrogen
atoms were refined with anisotropic displacement parameters. The
locations of the largest peaks in the final difference Fourier map
calculation as well as the magnitude of the residual electron densities
were of no chemical significance. In 5, one trifluoromethyl group
was found to be disordered and accordingly modeled. Crystals of
6 and 11 were found to contain lattice disordered solvent molecules
(toluene), which could not be sufficiently modeled in the refinement
cycles. These molecules were removed using the SQUEEZE
procedure40 implemented in the PLATON package.41 Crystal data
and details of data collection and structure refinement for the
different compounds are given in Table 1. Crystallographic data
are also available as cif files (see the Supporting Information).
Ethylene Polymerization. Polymerization experiments (Table
2) were performed in a 320 mL high-pressure glass reactor equipped
with a mechanical stirrer and externally heated with a double mantle
with a circulating water bath as desired. The reactor was filled with
toluene (50 mL) and MAO (30 wt % solution in toluene, 3.0-3.8
mL, 1100-1500 equiv) or Al(iBu)3 (0.5-3.2 mL, 40-100 equiv)
and [Ph3C][B(C6F5)4] (25-60 mg, 2-3 equiv) and pressurized at
7-8 atm of ethylene (Air Liquide, 99.99%). The reactor was
thermally equilibrated at the desired temperature for 1 h. Ethylene
pressure was decreased to 1 atm, and the catalyst precursor (12-32
µmol) in toluene (ca. 1 mL) was added by syringe. The ethylene
pressure was immediately increased to 7-8 atm, and the solution
was stirred for the desired time. Ethylene consumption was
monitored using an electronic manometer connected to a secondary
100 mL ethylene tank, which feeds the reactor by maintaining
constant the total pressure. The polymerization was stopped by
venting of the vessel and quenching with a 10% HCl solution in
methanol (ca. 3 mL). The polymer was precipitated in methanol
(ca. 200 mL), and 35% aqueous HCl (ca. 1 mL) was added to
dissolve possible catalyst residues. The polymer was collected by
filtration, washed with methanol (ca. 200 mL), and dried under
vacuum overnight.
1
69%). H NMR (500 MHz, THF-d8, 298 K): δ 1.79 (s, 3H, CH3),
3
2.64 (s, 2H, CH2), 6.60 (br d, 2H, o-Ph), 7.00 (t, JHH ) 7.8, 1H,
p-Ph), 7.22 (m, 2H, m-Ph). 19F{1H} NMR (188 MHz, THF-d8, 298
K): δ -81.0 (s, 6F, CF3). Anal. Calcd for C12H10F6NNaO: C, 44.87;
H, 3.14; N, 4.36. Found: C, 45.0; H, 3.2; N, 4.2.
Reaction of {ONR1,R2}H with KH: Synthesis of {ONR1,R2}K
and {ON-R1,R2}K2. (a) {ONMe,ArF}K. This compound was prepared
following a similar procedure to the one described above for
{ONPh,Ph}Na, starting from {ONMe,ArF}H (120 mg, 0.308 mmol)
and KH (13.0 mg, 0.324 mmol). {ONMe,Ph}K was obtained as a
1
white powder (80 mg, 61%). H NMR (500 MHz, THF-d8, 298
K): δ 2.04 (s, 3H, CH3), 2.81 (s, 2H, CH2). 19F{1H} NMR (188
MHz, THF-d8, 298 K): δ -167.4 (t, 3JCF ) 20.7, 1F, p-CF), -166.5
3
3
(t, JCF ) 20.7, 2F, m-CF), -154.7 (d, JCF ) 20.7, 2F, o-CF),
-79.2 (s, 6F, CF3).
(b) {ONMe,Ph}K. This compound was prepared following a
similar procedure to the one described above for {ONPh,Ph}Na,
starting from {ONMe,Ph}H (99.0 mg, 0.331 mmol) and KH (13.2
mg, 0.331 mmol). The reaction time was 1 h, and {ONMe,Ph}K was
obtained as an off-white powder (72 mg, 65%). 1H NMR (500 MHz,
THF-d8, 298 K): δ 1.82 (s, 3H, CH3), 2.65 (s, 2H, CH2), 6.61 (d,
3JHH ) 7.9, 2H, o-Ph), 6.96 (t, 3JHH ) 7.9, 1H, p-Ph), 7.21 (t, 3JHH
) 7.9, 2H, m-Ph). 19F{1H} NMR (188 MHz, THF-d8, 298 K): δ
-78.8 (s, 6F, CF3).
Melting temperatures of PE samples were determined on a
Perkin-Elmer Pyris 1 differential scanning calorimeter (10 °C/min,
nitrogen flow, first pass). Gel permeation chromatography (GPC)
analyses were performed at the University of Chicago on a Polymer
Laboratories PL-GPC 220 instrument using 1,2,4-trichlorobenzene
as solvent (stabilized with 125 ppm BHT) at 150 °C. A set of three
PLgel 10 µm Mixed-B or Mixed-B LS columns was used. Samples
were prepared at 160 °C and filtered through 2 or 5 µm stainless
steel frits prior to injection. Molecular weights were determined
versus polystyrene standards and are reported relative to polyeth-
ylene standards, as calculated by the universal calibration method
using Mark-Houwink parameters (K ) 17.5 × 10-5, R ) 0.670
for polystyrene; K ) 40.6 × 10-5, R ) 0.725 for polyethylene).
(c) {ON-Me,Ph}K2. This compound was prepared as described
above, starting from {ONMe,Ph}H (100 mg, 0.334 mmol) and KH
(26.7 mg, 0.667 mmol) and leaving the reaction overnight.
{ON-Me,Ph}K2 was obtained as an off-white powder (86 mg, 69%).
1H NMR (500 MHz, THF-d8, 298 K): δ 1.68 (s, 3H, CH3), 4.87 (s,
1H, dCH), 6.63 (d, 3JHH ) 7.6, 2H, o-Ph), 6.85 (t, 3JHH ) 7.6, 1H,
3
p-Ph), 7.16 (t, JHH ) 7.6, 2H, m-Ph). 19F{1H} NMR (188 MHz,
THF-d8, 298 K): δ -75.6 (s, 6F, CF3). Anal. Calcd for
C12H9F6K2NO: C, 38.39; H, 2.42; N, 3.73. Found: C, 38.1; H, 2.5;
N, 3.7.
Crystal Structure Determinations. As stated above, suitable
crystals for X-ray diffraction analysis of 1, 3a, 4, 5, 6, 7a, 7b, 7d,
8a, and 11 were obtained by recrystallization of purified products
or in the course of synthetic reactions. Diffraction data were
collected at 100 K using a Bruker APEX CCD diffractometer with
graphite-monochromated Mo KR radiation (λ ) 0.71073 Å). A
combination of ω and φ scans was carried out to obtain at least a
unique data set. The crystal structures were solved by means of
the Patterson method; remaining atoms were located from difference
Fourier synthesis followed by full-matrix least-squares refinement
based on F2 (programs SHELXS-97 and SHELXL-97).39 Many
hydrogen atoms could be found from the Fourier difference analysis.
Carbon-bound hydrogen atoms were placed at calculated positions
Acknowledgment. This work was financially supported
in part by Agence Nationale de la Recherche (grant ANR-
06-BLAN-0213) and Total Co. (Ph.D. grant to N.M.;
postdoctoral fellowship to E.K.). We are most grateful to
Prof. R. F. Jordan (Univ. Chicago) for HT-GPC analyses.
J.F.C. thanks the Institut Universitaire de France for a Junior
IUF fellowship (2005-2009).
Supporting Information Available: Crystallographic data for
1, 3a, 4, 5, 6, 7a, 7b, 7d, 8a, and 11 as CIF files; representative
GPC traces and DSC profiles of PEs prepared. This material is
available free of charge via the Internet at http://pubs.acs.org.
OM8009409
(39) (a) Sheldrick, G. M. SHELXS-97, Program for the Determination
of Crystal Structures; University of Goettingen: Germany, 1997. (b)
Sheldrick, G. M. SHELXL-97, Program for the Refinement of Crystal
Structures; University of Goettingen: Germany, 1997.
(40) van der Sluis, P.; Spek, A. L. Acta Crystallogr. 1990, A46, 194.
(41) Spek, A. L. Acta Crystallogr. 1990, A46, C-34.