Synthesis, Stereochemistry, and Reactivity of Group 4 Metal Complexes that Contain a Chiral Tetradentate Diamine-Diamide Ligand

Article abstract of DOI:10.1021/om0340443

Ti and Zr complexes of the new chiral tetradentate diamine-diamide ligand (Me₂PMEN)^2- are described (H₂(Me ₂PMEN), 1 = N,N′-dimethyl-N,N′-bis[(S)-2-methylpyrrolidine]ethylenediamine). The reaction of 1 with Zr(NMe₂)₄ affords (Me ₂PMEN)Zr(NMe₂)₂ (C₂-2) which is shown by NMR to have effective C₂-symmetry in solution. Addition of excess ClSiMe₃ to C₂-2 gives (Me₂PMEN)ZrCl ₂ (3) as a mixture of two isomers, C₂-3 (kinetic product) and C₁-3 (thermodynamic product). An X-ray diffraction study of C₁-3 revealed a distorted octahedral structure with a cis-amide/cis-chloride arrangement of ligands. Reaction of C₁/C ₂-3 with MeLi yields (Me₂PMEN)ZrMe₂ (C ₂-4), which exists as a single C₂-symmetric isomer in solution. The reaction of 1 and Zr(CH₂Ph)₄ affords (Me₂PMEN)Zr(CH₂Ph)₂ (5), which can be isolated as a mixture of two isomers, C₁-5 (kinetic product) and C ₂-5 (thermodynamic product). The Ti derivative (Me ₂PMEN)Ti(CH₂Ph)₂ (C₂-6) was prepared similarly from 1 and Ti(CH₂Ph)₄. Compound 6 shows effective C₂-symmetry in solution. An X-ray study of 6 revealed a C₂symmetric distorted octahedral structure with a trans-amide/cis-benzyl arrangement of ligands. Iodinolysis of C₂-6 followed by alkylation with MeMgCl leads to the unstable dimethyl derivative (Me₂PMEN)TiMe₂ (C₂-7). Alkyl abstraction from C₂-4, C₁/C₂-5, and C₂-6 using [Ph₃C][B(C₆F₅)₄], [HNMe ₂Ph][B(C₆F₅)₄], [HNMePh ₂][B(C₆F₅)₄], or B(C ₆F₅)₃ affords cationic alkyl complexes, of which [(Me₂PMEN)M(CH₂Ph)] [B(C₆F ₅)₄] (M = Ti, 8; M = Zr, 9) were isolated. In situ-generated 8 and 9 are moderately active ethylene polymerization catalysts.

Full text of DOI:10.1021/om0340443

Organometallics 2003, 22, 4999-5010
4999
Syn th esis, Ster eoch em istr y, a n d Rea ctivity of Gr ou p 4
Meta l Com p lexes Th a t Con ta in a Ch ir a l Tetr a d en ta te
Dia m in e-Dia m id e Liga n d
J ean-Franc¸ois Carpentier,†,‡ Alfredo Martin,‡ Dale C. Swenson,‡ and
Richard F. J ordan*,§
Department of Chemistry, The University of Chicago, 5735 S. Ellis Avenue,
Chicago, Illinois 60637, and Department of Chemistry, The University of Iowa,
Iowa City, Iowa 52242
Received J uly 16, 2003
Ti and Zr complexes of the new chiral tetradentate diamine-diamide ligand (Me2PMEN)2-
are described (H2(Me2PMEN), 1 ) N,N′-dimethyl-N,N′-bis[(S)-2-methylpyrrolidine]ethyl-
enediamine). The reaction of 1 with Zr(NMe2)4 affords (Me2PMEN)Zr(NMe2)2 (C2-2) which
is shown by NMR to have effective C2-symmetry in solution. Addition of excess ClSiMe3 to
C2-2 gives (Me2PMEN)ZrCl2 (3) as a mixture of two isomers, C2-3 (kinetic product) and C1-3
(thermodynamic product). An X-ray diffraction study of C1-3 revealed a distorted octahedral
structure with a cis-amide/cis-chloride arrangement of ligands. Reaction of C1/C2-3 with MeLi
yields (Me2PMEN)ZrMe2 (C2-4), which exists as a single C2-symmetric isomer in solution.
The reaction of 1 and Zr(CH2Ph)4 affords (Me2PMEN)Zr(CH2Ph)2 (5), which can be isolated
as a mixture of two isomers, C1-5 (kinetic product) and C2-5 (thermodynamic product). The
Ti derivative (Me2PMEN)Ti(CH2Ph)2 (C2-6) was prepared similarly from 1 and Ti(CH2Ph)4.
Compound 6 shows effective C2-symmetry in solution. An X-ray study of 6 revealed a C2-
symmetric distorted octahedral structure with a trans-amide/cis-benzyl arrangement of
ligands. Iodinolysis of C2-6 followed by alkylation with MeMgCl leads to the unstable dimethyl
derivative (Me2PMEN)TiMe2 (C2-7). Alkyl abstraction from C2-4, C1/C2-5, and C2-6 using
[Ph3C][B(C6F5)4], [HNMe2Ph][B(C6F5)4], [HNMePh2][B(C6F5)4], or B(C6F5)3 affords cationic
alkyl complexes, of which [(Me2PMEN)M(CH2Ph)][B(C6F5)4] (M ) Ti, 8; M ) Zr, 9) were
isolated. In situ-generated 8 and 9 are moderately active ethylene polymerization catalysts.
In tr od u ction
coordinate in a more selective manner. Several chiral
tetraamines that contain two pyrrolidine groups, in-
cluding H4(PMEN) and H4(PPM) (Chart 1), have been
prepared previously, and Mn(III), Co(III), Rh(I), Ir(I),
Ni(II), and Cu(II) complexes of these ligands have been
characterized.6
Group 4 metal complexes that contain tetradentate
nitrogen donor ligands, including porphyrins, tetraaza-
[14]-annulenes, and other tetradentate N-based mac-
rocycles,1 have been studied extensively in the last
decade.2 One driving force for this work is the interest
in the design of nonmetallocene single-site catalysts for
the polymerization of R-olefins.3 An attractive goal in
this area is to develop chiral metal complexes that
incorporate readily available chiral amide ligands for
exploitation in stereoselective catalysis.4 Here we de-
scribe Zr and Ti complexes that incorporate the new
tetradentate diamine-diamide ligand Me2PMEN2-, de-
rived by double deprotonation of the parent tetraamine
N,N′-dimethyl-N,N′-bis[(S)-2-methylpyrrolidine]ethyl-
enediamine (H2(Me2PMEN), 1, Chart 1).
(1) (a) Martin, A.; Uhrhammer, R.; Gardner, T. G.; J ordan, R. F.;
Rogers, R. D. Organometallics 1998, 17, 382. (b) Black, D. G.; Swenson,
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Uhrhammer, R.; Black, D. G.; Gardner, T. G.; Olsen, J . D.; J ordan, R.
F. J . Am. Chem. Soc. 1993, 115, 8493. (d) Giannini, L.; Solari, E.; De
Angelis, S.; Ward, T. R.; Floriani, C.; Chiesi-Villa, A.; Rizzoli, C. J .
Am. Chem. Soc. 1995, 117, 5801. (e) De Angelis, S.; Solari, E.; Gallo,
E.; Floriani, C.; Chiesi-Villa, A.; Rizzoli, C. Inorg. Chem. 1992, 31, 2520.
(f) Floriani, C.; Ciurli, S.; Chiesi-Villa, A.; Guastini, C. Angew. Chem.,
Int. Ed. Engl. 1987, 26, 70. (g) Cotton, F. A.; Czuchajowska, J .
Polyhedron 1990, 9, 2553. (h) Oberthu¨r, M.; Arndt, P.; Kempe, R.
Chem. Ber. 1996, 129, 1087. (i) Fuhrmann, H.; Brenner, S.; Arndt, P.;
Kempe, R. Inorg. Chem. 1996, 35, 6742. (j) Housmekerides, C. E.;
Ramage, D. L.; Kritz, C. M.; Shontz, J . T.; Pilato, R. S.; Geoffroy, G.
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Hagadorn, J . R.; Arnold, J . Angew. Chem., Int. Ed. 1998, 37, 1729. (l)
Scott, M. J .; Lippard, S. J . J . Am. Chem. Soc. 1997, 119, 3411. (m)
Brand, H.; Arnold, J . Coord. Chem. Rev. 1995, 140, 137. (n) Brand,
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Morton, C.; Gillepsie, K. M.; Sanders, C. J .; Scott, P. J . Organomet.
Chem. 2000, 606, 141. (p) O’Shaughnessy, P. N.; Gillepsie, K. M.;
Morton, C.; Westmoreland, I.; Scott, P. Organometallics 2002, 21, 4496.
(q) Westmoreland, I.; Munslow, I. J .; O’Shaughnessy, P. N.; Scott, P.
Organometallics 2003, 22, 2972. (r) Male, N. A. H.; Skinner, M. E. G.;
Bylikin, S. Y.; Wilson, P. J .; Mountford, P., Schro¨der, M. Inorg. Chem.
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2002, 41, 1110.
The coordination of linear tetradentate N-based ligands
to a hexacoordinate metal center can produce many
geometrical and optical isomers.5 However, tetradentate
ligands that incorporate defined chiral centers may
* To whom correspondence should be addressed. Fax: (+1)773-702-
0805. E-mail: rfjordan@uchicago.edu.
† Present address: UMR 6509 CNRS-Universite´ de Rennes 1,
Institut de Chimie, 35042 Rennes Cedex, France.
‡ The University of Iowa.
§ The University of Chicago.
10.1021/om0340443 CCC: $25.00 © 2003 American Chemical Society
Publication on Web 10/28/2003

5000 Organometallics, Vol. 22, No. 24, 2003
Carpentier et al.
(S)-(2-hydroxymethyl)pyrrolidine; (ii) the
Ch a r t 1
able
(Me2PMEN)2- ligand is flexible and therefore should
be able to coordinate to a variety of metals; and (iii)
H2(Me2PMEN) has C2-symmetry, which may lead to
C2-symmetric structures for (Me2PMEN)MX2 com-
plexes. Assuming an ideal octahedral arrangement, 12
(Me2PMEN)MX2 isomeric structures are possible
(A-L, Chart 2), of which four have C2-symmetry. These
structures differ in the arrangement (cis vs trans) of the
pairs of amide and X ligands and in the configuration
of the amine nitrogens.
Resu lts a n d Discu ssion
Liga n d Syn th esis. The tetraamine (S,S)-H2(Me2-
PMEN) (1) was prepared from (S)-(2-hydroxymethyl)-
pyrrolidine as shown in Scheme 1. The reaction of 2
equiv of (S)-(2-iodomethyl)pyrrolidine with N,N′-di-
methylethylenediamine affords the ditosyl derivative
Ts2(Me2PMEN), contaminated by ca. 30% of the mono-
(pyrrolidinyl)ethylenediamine alkylation product.8 Re-
duction of this crude mixture by excess LiAlH4 affords
1 as a colorless oil in overall 32% yield after workup.8
Syn th esis of (Me2P MEN)Zr X2 Com p lexes. The
amine elimination reaction of 1 and Zr(NMe2)4 yields
(Me2PMEN)Zr(NMe2)2 (C2-2) in 61% isolated yield as a
white solid (Scheme 2).9 1H NMR data indicate that the
yield of C2-2 is essentially quantitative, but the high
solubility of C2-2 in hydrocarbons and chlorinated
solvents reduces the isolated yield. 1H and 13C NMR
data establish that 2 has C2-symmetry on the NMR time
scale between -60 and 100 °C in toluene-d8 solution.
The new ligand (Me2PMEN)2- was designed by modi-
fication of H4(PMEN)7 considering the following fea-
tures: (i) H2(Me2PMEN) is readily prepared in enantio-
merically pure form starting from commercially avail-
(2) For related (R2N)2MX2 chemistry, see: (a) Andersen, R. A. Inorg.
Chem. 1979, 18, 2928. (b) Andersen, R. A. J . Organomet. Chem. 1980,
192, 189. (c) Planalp, R. P.; Andersen, R. A.; Zalkin, A. Organometallics
1983, 2, 16. (d) Bu¨rger, V. H.; Wiegl, K. Z. Anorg. Allg. Chem. 1973,
398, 257. (e) Bu¨rger, V. H.; Neese, H. J . Z. Anorg. Allg. Chem. 1969,
370, 275. (f) Bu¨rger, V. H.; Kluess, C.; Neese, H. J . Z. Anorg. Allg.
Chem. 1971, 381, 198. (g) Minhas, R. K.; Scoles, L.; Wong, S.;
Gambarotta, S. Organometallics 1996, 15, 1113. (h) Herrmann, W. A.;
Huber, N. W.; Behm, J . Chem. Ber. 1992, 125, 1405. (i) Horton, A. D.;
de With, J . J . Chem. Soc., Chem. Commun. 1996, 1375. (j) Canich, J .
M.; Turner, H.; W. World Patent 92/12162, 1992. (k) Bradley, D. C.;
Chisholm, M. H. Acc. Chem. Res. 1976, 9, 273. (l) Shah, S. A. A.; Dorn,
H.; Voigt, A.; Roesky, H. W.; Parisini, E.; Schmidt, H. G.; Noltemeyer,
M. Organometallics 1996, 15, 3176.
1
The assignment of the H NMR spectrum of C2-2 (see
Chart 1 for the Me2PMEN2- numbering scheme) was
made on the basis of a COSY experiment. The H-5
resonances appear at δ 4.3 (ddd) and 3.3 (m), the latter
overlapping with the H-2 resonance, the H-γ resonances
appear as two doublets at δ 2.62 and 1.70, and the H-R
resonances comprise two doublets of doublets at δ 2.25
and 2.20. A single Me2PMEN N-CH3 resonance is
observed at δ 2.13 (6H). The 13C NMR spectrum
contains seven resonances for the Me2PMEN2- ligand,
consistent with C2-symmetry.
Addition of excess ClSiMe3 to C2-2 gives (Me2PMEN)-
ZrCl2 (3), which was isolated in 61% yield as pale yellow
crystals (Scheme 2). The yield of 3 is essentially
quantitative according to NMR data,10 but again isola-
tion is hampered by the high solubility of this complex.
1H NMR monitoring experiments show that the reaction
proceeds via a monochloro intermediate, (Me2PMEN)-
ZrCl(NMe2), which is transformed to a C2-symmetric
dichloride complex (C2-3). C2-3 is slowly transformed to
a C1-symmetric isomer. The equilibrium ratio [C2-3]/
[C1-3] ) 13/87 is reached after 2 days in C6D6 at 23 °C.11
The two isomers of 3 are easily differentiated by 1H
NMR spectroscopy. The pattern of H-5, H-2, H-γ, and
(3) For recent reviews on olefin polymerization catalyzed by group
4 nonmetallocene complexes, see: (a) Britovsek, G. J . P.; Gibson, V.
C.; Wass, D. F. Angew. Chem., Int. Ed. 1999, 38, 428. (b) Gibson, V.
C.; Spitzmesser, S. K. Chem. Rev. 2003, 103, 283. (c) Coates, G. W.;
Hustad, P. D.; Reinartz, S. Angew. Chem., Int. Ed. 2002, 41, 2236.
(4) For representative examples of group 4 metal complexes contain-
ing chiral bidentate diamido ligands, see: (a) Cloke, F. G. N.; Geldbach,
T. J .; Hitchcock, P. B.; Love, J . B. J . Organomet. Chem. 1996, 506,
343. (b) Pritchett, S.; Gantzel, P.; Walsh, P. J . Organometallics 1997,
16, 5130. (c) Pritchett, S.; Woodmansee, D. H.; Gantzel, P.; Walsh, P.
J . J . Am. Chem. Soc. 1998, 120, 6423. (d) Armistead, L. T.; White, P.
S.; Gagne´, M. R. Organometallics 1998, 17, 216. (e) Tsuie, B.; Swenson,
D. C.; J ordan, R. F.; Petersen, J . L. Organometallics 1997, 16, 1392.
(f) Male, N. A. H.; Thornton-Pett, M.; Bochmann, M. J . Chem. Soc.,
Dalton Trans. 1997, 2487. (g) Flora, M. A.; Manzoni, M. R.; Baumann,
R.; Davis, W. M.; Schrock, R. R. Organometallics 1998, 18, 3220.
(5) For example, see the coordination chemistry of triethylenetet-
ramine (triene): (a) Basolo, F. J . Am. Chem. Soc. 1948, 70, 2634. (b)
Buckimgham, D. A.; Marzilli, P. A.; Sargeson, A. M. Inorg. Chem. 1967,
6, 1032. (c) Sargeson, A. M.; Searle, G. H. Inorg. Chem. 1967, 6, 787.
(6) H4(PMEN), N,N′-bis[(S)-2-methylpyrrolidine]ethane-1,2-diamine;
H4(PPM), N,N′-bis[(S)-2-methylpyrrolidine]propane-1,3-diamine. (a)
Kitagawa, S.; Murakami, T.; Hatano, M. Inorg. Chem. 1975, 14, 2347.
(b) Comba, P.; Hambley, T. W.; Lawrence, G. A.; Martin, L. L.; Renold,
P.; Varnagy, K. J . Chem. Soc., Dalton Trans. 1991, 277. (c) Bernhardt,
P. V.; Comba, P.; Hambley, T. W.; Martin, L. L.; Varnagy, K.; Zipper,
L. Helv. Chim. Acta 1992, 75, 145. (d) Bernhardt, P. V.; Comba, P.;
Gyr, T.; Varnagy, K. Inorg. Chem. 1992, 31, 1220. (e) Bernhardt, P.
V.; Comba, P.; Hambley, T. W.; Sovago, I.; Varnagy, K. J . Chem. Soc.,
Dalton Trans. 1993, 2023. (f) Kim, D.-Y.; Lee, D.-J .; Heo, N. H.; J ung,
M.-J .; Lee, B.-W.; Oh, C.-E.; Doh, M.-K. Inorg. Chim. Acta 1998, 267,
127. (g) Alcon, M. J .; Gutierrez-Puebla, E.; Iglesias, M.; Monge, M. A.;
Sanchez, F. Inorg. Chim. Acta 2000, 306, 117. (h) Alcon, M. J .; Iglesias,
M.; Sanchez, F.; Viani, I. J . Organomet. Chem. 2000, 601, 284. (i) Alcon,
M. J .; Corma, A.; Iglesias, M.; Sanchez, F. J . Mol. Catal. A: Chem.
2002, 178, 253.
(8) For a similar alkylation reaction and the subsequent reduction
of the N-tosylamine see: Tuladhar, S. M., D’Silva, C. Tetrahedron Lett.
1992, 33, 2203.
(9) (a) Bradley, D. C.; Thomas, I. M. Proc. Chem. Soc., London 1959,
225. (b) Bradley, D. C.; Thomas, I. M. J . Chem. Soc. 1960, 3857. (c)
Chisholm, M. H.; Hammond, C. E.; Hoffman, J . C. Polyhedron 1988,
7, 2515. (d) Diamond, G. M.; J ordan, R. F.; Petersen, J . L. J . Am. Chem.
Soc. 1996, 118, 8024.
(7) The nomenclature adopted for
1
follows that used for H4-
(10) The fact that 3 is formed quantitatively in the reaction of C2-2
and excess ClSiMe3 shows that the Me2PMEN amide groups are much
less reactive than the NMe2 groups.
(PMEN)6a and accounts for the substitution of the two exocyclic NH
residues by NMe groups.

Chiral Tetradentate Diamine-Diamide Ligand
Organometallics, Vol. 22, No. 24, 2003 5001
Ch a r t 2. P ossible Isom er s for Octa h ed r a l (Me2P MEN)MX2 Com p lexesa
a
The four entries in the descriptor refer to the arrangement of amide ligands, the arrangement of X ligands, the configuration
of Na, and the configuration of Nb, respectively. Note that the amine ligands must be cis.
Sch em e 1
K, Chart 2). The N-Zr-N angles in the five-membered
chelate rings (N(1)-Zr-N(7) 72.1(2)°, N(16)-Zr-N(10)
74.5(2)°, N(7)-Zr-N(10) 73.8(2)°) are much smaller
than the ideal octahedral value due to the chelation,
while the N(amide)-Zr-Cl angles are correspondingly
larger (N(16)-Zr-Cl(1) 104.7(2)°, N(7)-Zr-Cl(2) 113.2-
(2)°, N(16)-Zr-Cl(2) 99.0(2)°, N(1)-Zr-Cl(2) 96.9(2)°).
The Cl(1)-Zr-Cl(2) angle is 91.04(9)°. The geometry at
the amide nitrogens is planar (∑(angles): N(1) 359.6°,
N(16) 358.9°). The Zr-N(amide) distances (2.039(6) and
2.038(6) Å) are similar to those in other zirconium-amide
complexes,4f,12 and the Zr-N(amine) distances are ca.
0.4 Å longer than those values. The Zr-Cl(2) bond
(2.457(2) Å) is slightly shorter than the Zr-Cl(1) bond
(2.510(2) Å), as expected from the difference in trans
influence of the N(10) amino and N(1) amido groups.
Syn th esis of (Me2P MEN)Zr R2 Com p lexes. The
addition of 2 equiv of MeLi to a benzene solution of C1-3
or a mixture of C1-3/C2-3 cleanly affords (Me2PMEN)-
ZrMe2 (C2-4), which can be isolated in moderate yield
as colorless crystals (Scheme 2). The most convenient
synthesis of C2-4 (overall yield 67%) is a one-pot
synthesis directly from C2-2 without isolation of 3.
Regardless of the isomer ratio of the starting material
3, only one C2-symmetric isomer of 4 is observed by
NMR spectroscopy in benzene-d6 solution. The 1H NMR
spectrum of C2-4 was assigned on the basis of COSY
and NOESY experiments. The NOESY spectrum in-
H-R resonances observed for C2-3 is very similar to that
for C2-2. C2-3 exhibits one N-CH3 1H NMR resonance,
while C1-3 exhibits two. The 13C NMR spectra of C2-3
and C1-3 exhibit seven and 14 Me2PMEN2- resonances,
respectively.
Molecu la r St r u ct u r e of C1-(Me2P ME N)Zr Cl2
(C1-3). The solid state structure of C1-3 was determined
by X-ray crystallography and is shown in Figure 1.
Selected bond distances and angles are given in Table
1. C1-3 has a highly distorted octahedral structure with
a cis-amide/cis-chloride ligand arrangement (structure
(11) Rate constants for the isomerization of C2-3 to C1-3 (k ) 0.087-
(2) h-1, k′ ) 0.013(2) h-1; r ) 0.99; determined in the presence of 2
equiv of Me2NSiMe3) and C1-5 to C2-5 (k ) 0.0261(3) h-1, k′ ) 0.0046-
(3) h-1; r ) 0.996) were determined from 1H NMR spectra assuming a
reversible first-order reaction and using the relation ln(([A]0 - [A]∞)/
([A]t - [A]∞)) ) (k + k′)(t), where [A]0, [A]t, and [A]∞ are respectively
the concentration of the kinetic product (C2-3 or C1-5) at the beginning
of the reaction, at time t, and at equilibrium, k and k′ are the forward
(12) (a) Warren, T. H.; Schrock, R. R.; Davis, W, M. Organometallics
1998, 17, 308. (b) Gibson, V. C.; Kimberley, B. S.; White, A. J . P.;
Williams, D. J .; Howard, P. J . Chem. Soc., Chem. Commun. 1998, 313.
(c) Aoyagi, K.; Gantzel, P. K.; Kalai, K.; Tilley, T. D. Organometallics
1996, 15, 923. (d) Gue´rin, F.; McConville, D. H.; Vittal, J . J . Organo-
metallics 1996, 15, 5586.
and reverse rate constants, and
r is the correlation coefficient.
Emanuel, N. M.; Knorre, D. G. In Chemical Kinetics, Homogeneous
Reactions; Wiley: New York, 1973; pp 165-168.

5002 Organometallics, Vol. 22, No. 24, 2003
Carpentier et al.
F igu r e 1. Two views of the molecular structure of C1-(Me2PMEN)ZrCl2 (C1-3). The right view corresponds to structure K
in Chart 2. Hydrogen atoms and disordered C(13′) and C(14′) are omitted for clarity. Thermal ellipsoids are drawn at the
50% probability level.
Sch em e 2
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
The kinetic product is a C1-symmetric complex, which
is slowly and partially transformed to a C2-symmetric
isomer. The equilibrium ratio [C1-5]/[C2-5] ) 15/85 is
reached after 5 days in C6D6 at 23 °C.11
(d eg) for C1-3
Zr(1)-N(1)
Zr(1)-N(16)
Zr(1)-N(7)
2.039(6)
2.038(6)
2.464(6)
Zr(1)-N(10)
Zr(1)-Cl(1)
Zr(1)-Cl(2)
2.415(6)
2.510(2)
2.457(2)
The Zr-CH2Ph 1H NMR resonances of C2-5 appear
as two doublets at δ 2.45 and 2.11 (2J H-H ) 10.1 Hz),
and the ortho-Ph resonance appears as a low-field
doublet at δ 7.1. The Zr-CH2Ph 13C NMR resonance is
N(16)-Zr(1)-N(1)
N(16)-Zr(1)-N(10)
N(1)-Zr(1)-N(10)
N(16)-Zr(1)-Cl(2)
N(1)-Zr(1)-Cl(2)
N(10)-Zr(1)-Cl(2)
N(16)-Zr(1)-N(7)
N(7)-Zr(1)-Cl(1)
97.7(2) N(1)-Zr(1)-N(7)
74.5(2) N(10)-Zr(1)-N(7)
87.5(2) Cl(2)-Zr(1)-N(7)
72.1(2)
73.8(2)
113.2(2)
99.0(2) N(16)-Zr(1)-Cl(1) 104.7(2)
1
observed at δ 67.1 with J C-H ) 117 Hz. These data
96.9(2) N(1)-Zr(1)-Cl(1)
172.6(2) N(10)-Zr(1)-Cl(1)
147.0(2) Cl(2)-Zr(1)-Cl(1)
82.7(2)
154.7(2)
87.3(2)
91.04(9)
are consistent with normal η1-bonding of the benzyl
ligands.14 The 13C NMR spectrum of C1-5 displays two
1
Zr-CH2Ph resonances each with J C-H ) 117 Hz, also
consistent with η1-bonding of the benzyl groups.
cludes a correlation between the multiplet at δ 3.41-
3.34 that corresponds to H-2 and one H-5, and one H-γ
resonance (δ 2.78), which is consistent with either a type
E structure (close H-2‚‚‚H-γ contact) or a type F struc-
ture (close H-5‚‚‚H-γ contact), but not with structure A
or B (Chart 2). The 1H and 13C NMR Zr-CH3 reso-
nances of C2-4 appear at δ 0.39 and 35.1, respectively.
The reaction of 1 and Zr(CH2Ph)4 in toluene affords
(Me2PMEN)Zr(CH2Ph)2 (5), which was isolated in 76%
Syn th esis of (Me2P MEN)TiX2 Com p lexes. Halide
displacement and amine elimination routes did not
prove useful for the synthesis of (Me2PMEN)TiX2 com-
plexes. The amine elimination reaction of Ti(NMe2)4 and
1 in toluene at room temperature is complete within 3
h but gives a mixture of several products, of which the
expected product (Me2PMEN)Ti(NMe2)2 accounts for
1
only ca. 30% according to H NMR.15 As a result, this
species could be isolated only in very low (<5%) yield.
The reaction of TiCl4(THF)2 with in situ-generated
dilithium or magnesium salts16 of Me2PMEN2- yielded
1
yield as a pale beige powder (Scheme 2).13 A H NMR
monitoring experiment established that the reaction
proceeds quantitatively within 15 min at room temper-
ature in benzene-d6 with release of 2 equiv of toluene.
(14) (a) Guram, A. S.; J ordan, R. F. In Comprehensive Organome-
tallic Chemistry, 2nd ed.; Lappert, M. F., Ed.; Pergamon: Oxford, U.K.,
1995; Vol. 4, pp 589-625. (b) Crowther, D. J .; Borkowsky, S. L.;
Swenson, D.; Meyer, T. Y.; J ordan, R. F. Organometallics 1993, 12,
2897. (c) Hughes, A. K.; Meetsma, A.; Teuben, J . H. Organometallics
1993, 12, 1936. (c) Latesky, S. L.; McMullen, A. K.; Niccolai, G. P.;
Rothwell, I. P.; Huffman, J . C. Organometallics 1985, 4, 902.
(15) For examples of amine elimination from Ti(NR2)4 see refs 4b-d
and: (a) Bowen, D.; J ordan, R. F.; Rogers, R. D. Organometallics 1995,
14, 3630. (b) Kim, I.; Nishihara, Y.; J ordan, R. F.; Rogers, R. D.;
Rheingold, A. L.; Yap, G. P. A. Organometallics 1997, 16, 3314.
(13) (a) Collier, M. R.; Lappert, M. F.; Pearce, R. J . Chem. Soc.,
Dalton Trans. 1973, 445. (b) Lubben, T. V.; Wolczanski, P. T.; Van
Duyne, G. G. Organometallics 1984, 3, 977. (c) Latesky, S. L.;
McMullen, A. K.; Niccolai, G. P.; Rothwell, I. P. Organometallics 1985,
4, 902. (d) Chestnut, R. W.; Durfee, L. D.; Fanwick, P. E.; Rothwell, I.
P. Polyhedron 1987, 6, 2019. (e) Crowther, D. J .; Baezinger, N. C.;
J ordan, R. F. J . Am. Chem. Soc. 1991, 113, 1455. (f) Tjaden, E. B.;
Swenson, D. C.; J ordan, R. F.; Petersen, J . L. Organometallics 1995,
14, 371.

Chiral Tetradentate Diamine-Diamide Ligand
Organometallics, Vol. 22, No. 24, 2003 5003
F igu r e 2. Two views of the molecular structure of C2-(Me2PMEN)Ti(CH2Ph)2 (C2-6). In the right view, which corresponds
to structure E in Chart 2, the phenyl groups are removed; note that C19 and C26 are cis. Hydrogen atoms are omitted for
clarity. Thermal ellipsoids are drawn at the 30% probability level.
Sch em e 3
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
shorter than corresponding Zr-N bonds. This difference
also results in larger N(amide)-Ti-C(benzyl) angles
(N(16)-Ti-C(19) 98.4(3)°, N(1)-Ti-C(26) 100.5(3)°) and
a larger C(benzyl)-Ti-C(benzyl) angle (C(19)-Ti-C(26)
101.0(3)°) compared to the corresponding angles in
C1-3. The benzyl ligands are bonded in a normal
η1-mode, and the amide nitrogens are planar (sum of
the angles around N(1) ) 360.0°, N(16) ) 359.9°). A
C2 axis (noncrystallographic) passes through the Ti
atom and bisects the benzyl-Ti-benzyl angle. The
Ti-N(amide) distances are comparable to those found
in other Ti(IV)-amido complexes.16,17
(d eg) for C2-6
Ti(1)-N(1)
Ti(1)-N(16)
Ti(1)-N(7)
1.984(7)
1.944(8)
2.343(7)
Ti(1)-N(10)
Ti(1)-C(26)
Ti(1)-C(19)
2.290(7)
2.190(7)
2.210(7)
N(16)-Ti(1)-N(1)
N(16)-Ti(1)-N(10)
N(1)-Ti(1)-N(10)
N(16)-Ti(1)-C(26)
N(1)-Ti(1)-C(26)
170.9(3) N(1)-Ti(1)-N(7)
76.3(3) N(10)-Ti(1)-N(7)
96.1(3) C(19)-Ti(1)-N(7)
85.7(3) N(16)-Ti(1)-C(19)
100.5(3) N(1)-Ti(1)-C(19)
75.3(3)
77.4(3)
159.3(3)
98.4(3)
86.9(3)
94.3(3)
N(10)-Ti(1)-C(26) 157.9(3) N(10)-Ti(1)-C(19)
N(16)-Ti(1)-N(7)
N(7)-Ti(1)-C(26)
98.0(3) C(26)-Ti(1)-C(19) 101.0(3)
92.8(3) Ti(1)-C(19)-C(20) 122.9(5)
1H and 13C NMR spectroscopy establish that C2-6
retains its C2-symmetry on the NMR time scale between
-80 and 30 °C in CD2Cl2, toluene-d8, and benzene-d6
mixtures of unidentified products. However, alkane
elimination provides an entry to (Me2PMEN)TiX2 sys-
tems. The reaction of 1 and Ti(CH2Ph)4 in toluene yields
the dibenzyl derivative (Me2PMEN)Ti(CH2Ph)2 (C2-6)
cleanly (Scheme 3). This reaction proceeds rapidly at
room temperature, as evidenced by the precipitation of
6 after 10 min, and is complete within 3 h. Analytically
pure C2-6 was isolated in 85% yield as a brick red solid
by precipitation from toluene/pentane.
1
solutions. The H NMR spectrum was assigned on the
basis of COSY and NOESY experiments (CD2Cl2, 25 °C).
The NOESY spectrum includes a correlation between
H-2 (δ 3.85) and a H-γ (δ 3.26), which is consistent with
a type E structure (as found in the solid state) but not
with the other C2-symmetric structures A, B, or F
Molecu lar Str u ctu r e of C2-(Me2P MEN)Ti(CH2P h )2
(C2-6). Deep red crystals of C2-6 suitable for X-ray
analysis were grown from a saturated toluene solu-
tion at -30 °C. The molecular structure of C2-6 is
shown in Figure 2, and selected bond distances and
angles are given in Table 2. C2-6 has a type E struc-
ture. The N-Ti-N angles in the five-membered che-
late rings (N(1)-Ti-N(7) 75.3(3)°, N(10)-Ti-N(16)
76.3(3)°, N(7)-Ti-N(10) 77.4(3)°) are much smaller
than the ideal octahedral value, but to a lesser extent
than in C1-3 since Ti-N bonds are ca. 0.05-0.1 Å
(17) (a) Scollard, J . D.; McConville J . Am. Chem. Soc. 1996, 118,
10008. (b) Scollard, J . D.; McConville, Payne, N. C.; Vittal, J . J .
Macromolecules 1996, 29, 5241. (c) Scollard, J . D.; McConville, D. H.;
Vittal, J . J .; Payne, N. C. J . Mol. Catal. A: Chem. 1998, 128, 201. (d)
Scollard, J . D.; McConville, D. H.; Vittal, J . J . Organometallics 1995,
14, 5478. (e) Gue´rin, F.; McConville, D. H.; Payne, N. C. Organome-
tallics 1996, 15, 5085. (f) Aoyagi, K.; Gantzel, P. K.; Kalai, K.; Tilley,
T. D. Organometallics 1996, 15, 923. (g) J ones, R. A.; Seeberger, M.
H.; Atwood, J . L.; Hunter, W. E.; J . Organomet. Chem. 1983, 247, 1.
(h) Friedrich, S.; Gade, L. H.; Edwards, A. J .; McPartlin, M. J . Chem.
Soc., Dalton Trans. 1993, 32, 1959. (i) Cummins, C. C.; Schrock, R.
R.; Davis, W. M. Organometallics 1992, 11, 1452. (j) J ohnson, A. R.;
Davis, W. M.; Cummins, C. C. Organometallics 1996, 15, 3825. (k)
Scoles, L.; Minhas, R.; Duchateau, R.; J ubb, J .; Gambarotta, S.
Organometallics 1994, 13, 4978. (l) Herrmann, W. A.; Denk, M.; Albach,
R. W.; Behm, J .; Herdweck, E. Chem. Ber. 1991, 124, 683. (m) Clark,
H. C. S.; Cloke, F. G. N.; Hitchcock, P. B.; Love, J . B.; Wainwright, A.
P. J . Organomet. Chem. 1995, 501, 333.
(16) Warren, T. H.; Schrock, R. R.; Davis, W. M. Organometallics
1996, 15, 562.

5004 Organometallics, Vol. 22, No. 24, 2003
Carpentier et al.
Ta ble 3. Selected 1H NMR Da ta (C6D6) for
(Chart 2). Additionally, one of the H-3 resonances
appears at very high field (δ 0.23), consistent with the
anisotropic shielding by a phenyl ring. Therefore we
conclude that C2-6 has the same structure (type E) in
the solid state and solution.
C2-(Me2P MEN)MX2 Com p lexes 2-7
compound
δ H-R δ H-γ δ H-5 δ H-2 δ NCH3
C2-2
C2-3
C2-4
C2-5
C2-6
C2-7
2.20 2.25 1.70 2.62 3.30 4.30 3.35
2.35 2.78 1.95 2.93 3.22 4.75 3.28
2.16 2.43 1.23 2.78 3.35 4.61 3.37
1.95 2.26 1.10 2.61 3.20 4.35 3.25
2.02 2.55 1.16 2.58 3.60 4.83 3.55
2.15 2.50 1.20 2.73 3.80 5.04 3.65
2.13
2.34
1.93
1.83
1.81
1.78
The η1-bonding of the benzyl ligands observed in the
2
solid state was confirmed in solution by normal J H-H
1
(10.1 Hz) and J C-H (120 Hz) values for the Ti-CH2Ph
unit.14
Ta ble 4. Selected 13C NMR Da ta (C6D6) for
Syn th esis of (Me2P MEN)TiMe2 (C2-7). Compound
C2-6 was evaluated as a precursor to (Me2PMEN)TiMe2
through the intermediacy of the diiodide (Scheme 3).
The reaction of C2-6 with 2 equiv of I2 in toluene
C2-(Me2P MEN)MX2 Com p lexes 2-7
compound
δ C-R
δ C-γ
δ C-5
δ C-2
δ N-CH3
C2-2
C2-3
C2-4
C2-5
C2-6
C2-7
53.6
54.3
52.2
52.5
52.8
52.3
55.1
54.4
53.0
53.2
55.0
55.0
67.5
65.2
64.9
63.4
62.0
63.4
64.3
64.6
64.7
65.1
67.6
67.4
47.2
47.6
45.2
44.9
45.8
45.7
1
generates benzyl iodide (identified by H and 13C NMR
and GC-MS) and a brown precipitate, which was
isolated in 78% yield. This material is insoluble in
aliphatic and aromatic solvents and sparingly soluble
1
in CD2Cl2. The H NMR spectrum in CD2Cl2 contained
C2-6, which suggests that this species also has a type E
structure in solution.18 C2-4 and C2-5 likely adopt
structure E or F , because the other C2 structures A and
B feature mutually trans alkyl groups. Indeed, NOESY
data for C2-4 (correlation between a H-γ and H-2 or a
H-5) are consistent with type E or F structures but
inconsistent with structure A or B (vide supra). Con-
versely, structures I-L have one X- ligand trans to a
strong donor amido group, which is expected to be
favorable for weak donor X- ligands. This may account
for the conversion of the kinetic product C2-(Me2PMEN)-
ZrCl2 (C2-3) to the thermodynamic product C1-(Me2-
PMEN)ZrCl2 (C1-3). It is striking that of the four
possible I-L isomers, only one, structure K, is observed
for C1-3. Further studies will be required to unambigu-
ously establish the structures of the C2-symmetric
isomers of 2-5.
many resonances and was not informative about the
structure. However, the mass spectrum contained a
high-intensity peak envelope assigned by isotopic analy-
sis to (Me2PMEN)TiI+, which suggests that the brown
material is (Me2PMEN)TiI2. The loss of one X group
from the parent ion is a major mass spectral fragmenta-
tion process for the other (Me2PMEN)MX2 complexes
described here (see Experimental Section). The addi-
tion of 2 equiv of MeMgCl to an ether suspension of
crude (Me2PMEN)TiI2 at -78 °C affords (Me2PMEN)-
TiMe2 (C2-7) in 49% yield as a bright red gummy solid,
which is ca. 90% pure by NMR. Compound C2-7 is
thermally sensitive and decomposes within several
hours at 23 °C, either neat or in benzene solution, which
precluded further purification. Titanium dimethyl com-
plexes bearing amide ligands are known to form meth-
ylidene species by R-elimination.17e,k 7 exists as a single
C2-symmetric isomer in benzene-d6 solution. The 1H
NMR spectrum contains resonances for the Me2PMEN
Syn th esis of (Me2P MEN)MR+ Com p lexes. The
reaction of the Ti-dibenzyl complex C2-6 with
[HNMe2Ph][B(C6F5)4]19 in CD2Cl2 at -78 °C proceeds
rapidly (<10 min) and cleanly to afford a soluble
product, [(Me2PMEN)Ti(CH2Ph)][B(C6F5)4] (8), with
release of 1 equiv of toluene and NMe2Ph (Scheme 4).
The corresponding reaction of the Zr-dibenzyl complex
C2/C1-5 similarly affords [(Me2PMEN)Zr(CH2Ph)]-
1
ligand that are similar to those of C2-6. The H and 13C
NMR spectra of C2-7 display Ti-CH3 resonances at δ
0.81 and 47.9, respectively.
Ster eoselectivity of Me2P MEN2- Coor d in a tion .
An interesting aspect of this study is the stereoselec-
tivity of coordination of Me2PMEN2- to group 4 metal
centers. It is remarkable that for each (Me2PMEN)MX2
compound described here only a single C2-symmetric
isomer (2, 4, 6, 7) or a mixture of a single C2-symmetric
and a single C1-symmetric isomer (3, 5) is formed, out
of the 12 possible isomers (Chart 2). It appears that
C2-symmetric structures are generally favored. Only for
(Me2PMEN)ZrCl2 (3) is a C1-symmetric isomer thermo-
dynamically favored (structure K).
1
[B(C6F5)4] (9). The H and 13C NMR data for 8 and 9
establish that the NMe2Ph coproduct does not coordi-
nate to these cations between -80 and 25 °C, indicating
that 8 and 9 are rather poor Lewis acids. When the
reactions are performed in benzene at 23 °C, 8 and 9
are deposited as orange oils and can be isolated in 85%
(18) For a similar use of 13C NMR spectroscopy in the structural
analysis of geometrical isomers of coordination complexes with related
ligands, see: Strasak, M.; Bachraty, F. J . Coord. Chem. 1984, 13, 105.
(19) For the use of HNR3+ reagents with B(C6F5)4- type counterions
in the generation of LnM(R)+ species, see: (a) Bochmann, M.; Wilson,
L. M. J . Chem. Soc., Chem. Commun. 1986, 1610. (b) Lin, Z.; Le
Marechal, J .; Sabat, M.; Marks, T. J . J . Am. Chem. Soc. 1987, 109,
4127. (c) Turner, H. W.; Hlatky, G. G. Eur. Pat. Appl. 0 277 003, 1988.
(d) Turner, H. W. Eur. Pat. Appl. 0 277 004, 1988. (e) Hlatky, G. G.;
Eckman, R. R.; Turner, H. W. Organometallics 1992, 11, 1413. (f)
Eshuis, J . J . W.; Tan, Y. Y.; Meetsma, A.; Teuben, J . H.; Renkema, J .;
Evens, G. G. Organometallics 1992, 11, 362. (g) Amorose, D. M.; Lee,
R. P.; Petersen, J . L. Organometallics 1991, 10, 2191. (h) Horton, A.
D.; Orpen, A. G. Organometallics 1991, 10, 3910. (i) Bochmann, M.;
J agger, A. J .; Nicholls, J . C. Angew. Chem., Int. Ed. Engl. 1990, 29,
780. (j) Horton, A. G.; Frijins, J . H. G. Angew. Chem., Int. Ed. Engl.
1991, 30, 1152. (k) Grossman, R. B.; Doyle, R. A.; Buchwald, S. L.
Organometallics 1991, 10, 1501. (l) Bochmann, M.; Lancaster, S. J .
Organomet. Chem. 1992, 434, C1. (m) Guo, Z.; Swenson, D. C.; J ordan,
R. F. Organometallics 1994, 13, 1424.
These structural trends reflect the donor properties
of the X- ligands and the conformational preferences
of the Me2PMEN2- ligand. In structures E-H, the X-
ligands are trans to the weak donor amine groups,
which is expected to be favorable for cases with strong
donor X- ligands, i.e., dialkyl complexes 4-7. As noted
above, X-ray structural data, NOESY data (correlation
between H-2 and a H-γ), and NMR chemical shift data
(anisotropic shielding of a H-3 by Ti-CH2Ph) establish
that C2-6 adopts structure E in the solid state and in
solution. Additionally, as summarized in Tables 3 and
4, the 1H and 13C NMR data for the Me2PMEN2- ligand
of (Me2PMEN)TiMe2 (C2-7) are very similar to those of

Chiral Tetradentate Diamine-Diamide Ligand
Organometallics, Vol. 22, No. 24, 2003 5005
Sch em e 4
Sch em e 5
1
evolution (Scheme 5). H NMR monitoring established
and 92% yield, respectively, as orange powders by sepa-
ration from the supernatants, trituration with pen-
tane, and drying under vacuum. Compound 8 is stable
in CD2Cl2 for hours at room temperature and for days
at -40 °C, while 9 decomposes above -40 °C in this sol-
vent. These compounds were characterized by elemental
analysis and low-temperature NMR spectroscopy.
that several complexes are present in the first stage of
the reaction, but after 4 days at 23 °C, only one species,
assigned as THF-d8 complex 10, is observed. The 1H
and 13C NMR data establish that this species has
C1-symmetry. The 1H and 13C Zr-Me resonances appear
at δ -0.22 and δ 33.7, respectively, slightly upfield of
the corresponding resonances of C2-4.
Olefin P olym er iza tion Stu d ies. The ethylene and
1-hexene polymerization behavior of several cationic
species was briefly investigated. The (Me2PMEN)MR+
cations were generated in situ by reaction of C2-4,
C1/C2-5, and C2-6 with different activators in various
solvents, and their ethylene and 1-hexene polymeriza-
tion activities were compared under similar conditions.
As summarized in Table 5, (Me2PMEN)MR+ cations
exhibit poor to moderate ethylene polymerization activ-
ity, the activity order being (Me2PMEN)Zr(CH2Ph)+ (9)
> “(Me2PMEN)Zr(CH3)+” > (Me2PMEN)Ti(CH2Ph)+ (8).
None of these systems are active for 1-hexene polym-
erization under the conditions studied (0-23 °C, toluene
or chlorobenzene solvent, or neat 1-hexene).
1
The room-temperature H and 13C NMR spectra of 8
and the 1H NMR spectrum of 9 exhibit broad resonances
due to fluxionality. The low-temperature (-60 °C) 13C
NMR spectra of 8 and 9 each display 14 resonances for
the Me2PMEN backbone and five resonances for the
1
benzyl ligand. Also, the low-temperature (-40 °C) H
NMR spectra of 8 and 9 each contain two N-CH3
singlets, an AB pattern for the MCH2Ph unit, and one
ortho-Ph and one meta-Ph resonance. These data are
consistent with C1-symmetric structures with free rota-
tion around the ZrCH2-Ph bond.20 A weak η2-benzyl
interaction is suggested for both compounds by reduced
1
2J H-H values (8, 9.0 Hz; 9, 8.3 Hz) and increased J C-H
values (8, 127 Hz;21 9, 136 Hz) of the M-CH2Ph unit14
1
and by high-field ortho-Ph H resonances (8, δ 6.77; 9,
Exposure of a toluene solution of C2-4 and [Ph3C]-
[B(C6F5)4] (to generate (Me2PMEN)Zr(CH3)+) to 1.4 atm
of ethylene at 23 °C (entry 1) results in an exothermic
reaction, rapid (ca. 2 min) formation of solid polymer,
and discoloration of the initially orange-yellow reaction
mixture. These observations suggest that polymeriza-
tion is rapid but that rapid catalyst deactivation also
occurs; the average activity calculated over the whole
experiment time is therefore a lower limit. The polymer
produced under these conditions has a high molecular
weight with a very broad multimodal molecular weight
distribution, which may reflect the apparent complexity
of the reaction of C2-4 and the activator (vide supra)
and/or the changes in the reaction conditions during
polymerization.
Activation of 5 with [Ph3C][B(C6F5)4] or [HNMePh2]-
[B(C6F5)4] in toluene produces catalysts that display
similar ethylene polymerization activity and produce
polyethylene with similar properties (entries 3 and
5). These results suggest that the same active species,
i.e., 9, is generated in both cases. In contrast, the
catalyst generated by the reaction of 5 with B(C6F5)3,
presumed to be [(Me2PMEN)Zr(CH2Ph)][PhCH2B(C6F5)3],
is less active than 9 (entries 3 and 5 vs 6). When the
polymerization temperature is raised to 100 °C (entry
7), the activity of 9 increases and a polymer with a
lower molecular weight and a narrower polydispersity
(Mw/Mn ) 3.1, monomodal) is formed. When polymeriza-
tions are carried out in chlorobenzene in place of
toluene, the activities of both 9 and “(Me2PMEN)Zr-
(CH3)+” decrease (entries 2 and 4). Visual observations
(discoloration of reaction mixtures) suggest that catalyst
deactivation is faster in chlorobenzene than toluene for
zirconium species.
δ 6.82) and ipso-Ph 13C resonances (8, δ 146.8; 9, δ
142.3), compared to the corresponding data for neutral
dibenzyl complexes C2-6 and C2/C1-5. The 19F and 11B
NMR spectra show no evidence for B(C6F5)4- coordina-
tion. In parallel NMR scale reactions, complexes 8 and
9 were generated by the reaction of C2-6 and C2/C1-5,
respectively, with [Ph3C][B(C6F5)4]22 in chlorobenzene-
d5 (Scheme 4). The formation of Ph3CCH2Ph as a
coproduct was established by 1H and 13C NMR spec-
troscopy.
NMR scale reactions of the dimethyl-Zr derivative
C2-4 with [HNMePh2][B(C6F5)4], [Ph3C][B(C6F5)4], or
B(C6F5)3,23 in CD2Cl2, C2D4Cl2, or benzene-d6, led to
complex mixtures of products. The formation of free
NMePh2 and CH4 as coproducts in the first case and
1
Ph3CMe in the second case was confirmed by H and
13C NMR spectroscopy and suggests that (Me2PMEN)-
Zr(CH3)+ species are generated initially. The reaction
of C2-4 and [HNMePh2][B(C6F5)4] in THF-d8 at room
temperature proceeds rapidly (<10 min) with CH4
(20) Bei, X.; Swenson, D. C.; J ordan, R. F. Organometallics 1997,
16, 3282, and references therein.
1
(21) The J C-H coupling constant of 127 Hz for the TiCH2 group is
in the lower limit for an η2-benzyl character (1J C-H > 125 Hz).14 It has
been proposed for closely related benzyl Ti-diamide complexes that the
steric bulk of the ligand could prevent the close approach of the ipso
carbon to Ti, thus lowering the observed C-H coupling constant.17d
(22) For use of [Ph3C][B(C6F5)4] in the generation of LnM(R)+ species,
see: (a) Chien, J . C. W.; Tsai, W.; Rausch, M. D. J . Am. Chem. Soc.
1991, 113, 8570. (b) Ewen, J . A.; Elder, M. J . Makromol. Chem.,
Macromol. Symp. 1993, 66, 179. (c) Bochmann, M.; Lancaster, S. J .
Organomet. Chem. 1993, 12, 633. (d) Razavi, A.; Thewalt, U. J .
Organomet. Chem. 1993, 445, 111. (e) Straus, D. A.; Zhang, C.; Tilley,
T. D. J . Organomet. Chem. 1989, 369, C13.
(23) For use of B(C6F5)3 in the generation of LnM(R)+ species, see
ref 5 and: Yang, X.; Stern, C. L.; Marks, T. J . J . Am. Chem. Soc. 1994,
116, 10015, and references therein.

5006 Organometallics, Vol. 22, No. 24, 2003
Ta ble 5. Eth ylen e P olym er iza tion Da ta a
Carpentier et al.
f
time
(min)
yield
(mg)
Mw
Tm
f
entry
catalyst precursor
activator
solvent
activityb
(103)
Mw/Mn
(°C)g
1
ZrMe2[Me2PMEN] (C2-4)
ZrMe2[Me2PMEN] (C2-4)
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
[HNMe2Ph][B(C6F5)4]
B(C6F5)3
[HNMe2Ph][B(C6F5)4]
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
toluene
C6H5Cl
toluene
C6H5Cl
toluene
toluene
toluene
toluene
C6H5Cl
90
120
90
90
90
90
15
60
150
295
20
495
<5
625
117
305
50
3240
150
5430
<50
6850
1280
20100
825
546
nd
65.8
nd
67.8
nd
27.9
nd
148
nd
5.6
nd
6.3
nd
3.1
nd
132
nd
136
nd
134
nd
131
nd
2c
3
Zr(CH2Ph)2[Me2PMEN] (5)d
Zr(CH2Ph)2[Me2PMEN] (5)d
Zr(CH2Ph)2[Me2PMEN] (5)d
Zr(CH2Ph)2[Me2PMEN] (5)d
Zr(CH2Ph)2[Me2PMEN] (5)d
Ti(CH2Ph)2[Me2PMEN] (C2-6)
Ti(CH2Ph)2[Me2PMEN] (C2-6)
4
5
6
7e
8
9
170
1120
25.0
1.7
139
a
Unless otherwise stated, polymerization experiments were conducted at 23 °C under 20 psi (1.4 atm) of ethylene using 47.7 µmol of
b
catalyst precursor and 43.3 µmol of activator in 13 mL of solvent (see Experimental Section). Average activity calculated over the whole
polymerization time and expressed in (g of PE)‚(mol of activated catalyst)-1‚atm-1‚h-1
.
c 50.8 µmol of catalyst precursor and 46.6 µmol of
activator were used. 77/23 mixture of C1 and C2 isomers. e T ) 100 °C. f Determined by GPC. Determined by DSC.
d
g
1H, 13C, and 11B NMR spectra were recorded on a Bruker
The activity of (Me2PMEN)Ti(CH2Ph)+ (8), generated
in situ by the reaction of C2-6 with [Ph3C][B(C6F5)4] in
toluene, is significantly lower than that of 9 (entries 8
vs 3). In contrast to the Zr catalysts, the activity of 8
slightly increases when the polymerization is carried out
in chlorobenzene (entry 9). The polyethylene produced
under these conditions has a relatively low molecular
weight with a narrow monomodal molecular weight
distribution, characteristic of a single-site catalyst.
Con clu sion s. Alkane and amine elimination reac-
tions of the new chiral tetraamine H2(Me2PMEN) with
M(CH2Ph)4 (M ) Zr, Ti) and Zr(NMe2)4 provide efficient
access to (Me2PMEN)MX2 (X ) NMe2, Cl, CH2Ph, Me)
complexes. The coordination of the Me2PMEN2- ligand
to group 4 metals is highly stereoselective. For each
(Me2PMEN)MX2 compound prepared, only a single
C2-symmetric isomer (2, 4, 6, 7) or a mixture of a single
C2-symmetric and a single C1-symmetric isomer (3, 5)
is formed, out of the 12 possible isomers. It appears
that the structure of (Me2PMEN)MX2 complexes is
controlled by the donor properties of the X- ligands and
the conformational preferences of the Me2PMEN2-
ligand. Cationic (Me2PMEN)MR+ species are gene-
rated by protonolysis or alkyl abstraction reactions of
(Me2PMEN)MR2 complexes, of which (Me2PMEN)M(η2-
CH2Ph)+ (8, M ) Ti; 9, M ) Zr) were isolated in good
yields. Cations 8 and 9 catalyze ethylene polymerization
under mild conditions, but are inactive for 1-hexene
polymerization. Neither 8 nor 9 coordinates NMe2Ph,
which suggests that these species may be insufficiently
electrophilic to efficiently bind and activate R-olefins for
insertion.
AMX-360 spectrometer at ambient probe temperature (23 °C)
unless otherwise indicated. 19F NMR spectra were recorded
on a Bruker AC-300 spectrometer at ambient probe temper-
ature. 1H and 13C chemical shifts are reported versus SiMe4
1
and were determined by reference to the residual H and 13C
solvent peaks. 11B and 19F NMR spectra were referenced
externally to neat CFCl3 and BF3‚Et2O, respectively. All
coupling constants are given in Hz. Optical rotations were
recorded at room temperature using a 1 cm cell on a J ASCO
DIP-1000 polarimeter. Mass spectra were recorded on a VG
Analytical ZAB-HF instrument. Elemental analyses were
performed by Desert Analytics Laboratory (Tucson, AZ).
N,O-Ditosyl-(S)-2-(h yd r oxym eth yl)p yr r olid in e.26 A so-
lution of p-toluenesulfonyl chloride (39.7 g, 208 mmol) in dry
pyridine (130 mL) was placed under nitrogen and cooled to
-5 °C. A solution of (S)-2-(hydroxymethyl)pyrrolidine (9.62 g,
95.0 mmol) in pyridine (15 mL) was added over 3 min. The
mixture was stirred for 4 h at -5 °C and then allowed to
warm to room temperature. The reaction mixture was fur-
ther stirred for 0.5 h and poured into ca. 1.5 kg of ice. The
gummy orange-brown product was triturated, leading to the
progressive formation of a yellow-green solid. When all of the
ice was melted, the precipitate was collected by filtration,
washed thoroughly with water, and dried under vacuum
overnight (30.3 g, 78%). Anal. Calcd for C19H23NO5S2: C, 55.73;
H, 5.66; N, 3.42. Found: C, 55.60; H, 5.57; N, 3.48. 1H
NMR (CDCl3): δ 7.76 (d, J ) 8.3, 2H, o-Ph), 7.59 (d, J ) 8.2,
2H, o-Ph), 7.32 (d, J ) 8.1, 2H, m-Ph), 7.25 (d, J ) 8.0, 2H,
m-Ph), 4.20 (dd, J ) 9.9 and 3.6, 1H, CHHO), 3.91 (dd, J )
9.9 and 8.1, 1H, CHHO), 3.68 (m, 1H, CHN), 3.32 (m, 1H,
CHHN), 2.97 (m, 1H, CHHN), 2.41 (s, 3H, CH3), 2.37 (s, 3H,
CH3), 1.85-1.69 (m, 2H, CH2), 1.60-1.45 (m, 2H, CH2). 13C
NMR (CDCl3): δ 144.9 (m, i-Ph), 143.7 (m, i-Ph), 133.3 (m,
p-Ph), 132.4 (m, p-Ph), 129.8 (d, J C-H ) 160, o-Ph), 129.6
(d, J C-H ) 160, o-Ph), 127.8 (d, J C-H ) 165, m-Ph), 127.3 (d,
J C-H ) 163, m-Ph), 71.3 (t, J C-H ) 150, CH2O), 57.5 (d, J C-H
) 141, CHN), 49.1 (t, J C-H ) 142, CH2N), 28.3 (t, J C-H ) 134,
CH2), 23.5 (t, J C-H ) 139, CH2), 21.4 (q, J C-H ) 126, CH3),
21.3 (q, J C-H ) 126, CH3). [R]25D (c 0.65, acetone) ) -121. Mp:
96-98 °C. EI-MS: 254 (3), 237 (15), 224 (100), 155 (60), 91
(100), 65 (25).
Exp er im en ta l Section
Gen er a l P r oced u r es. All manipulations involving orga-
nometallic complexes were performed under a purified N2
atmosphere using standard high-vacuum, Schlenk, or glovebox
techniques. Solvents were distilled from Na/benzophenone
ketyl (THF, hexanes, pentane, diethyl ether, benzene, toluene)
or CaH2 (dichloromethane). (S)-(+)-2-(Hydroxymethyl)pyrro-
lidine (Aldrich, 99%) and the other reagents used for the
synthesis of H2(Me2PMEN) were purchased from ACROS or
Aldrich and used as received. The commercial reagents n-
butyllithium, methyllithium, methylmagnesium chloride, and
trimethylsilyl chloride (99%+, Aldrich) were used as received.
[Ph3C][B(C6F5)4] (Asahi Glass) and [HNMe2Ph][B(C6F5)4] (Boul-
der Scientific) were used as received. B(C6F5)3 (Boulder
Scientific) was sublimed before use. The following compounds
were prepared by literature methods: [HNMePh2][B(C6F5)4],24
Zr(NMe2)4,9 Ti(NMe2)4,9 Zr(CH2Ph)4,25 and Ti(CH2Ph)4.25
N-Tosyl-(S)-2-(iodom eth yl)pyr r olidin e.27 A slurry of N,O-
ditosyl-(S)-2-(hydroxymethyl)pyrrolidine (30.3 g, 74.0 mmol)
and NaI (13.3 g, 89.0 mmol) in dry acetone (160 mL) was
refluxed under nitrogen, protected from light with aluminum
(24) Tjaden, E. B.; Swenson, D. C.; J ordan, R. F. Organometallics
1995, 14, 371.
(25) Zucchini, U.; Albizzati, E.; Giannini, U. J . Organomet. Chem.
1971, 26, 357.
(26) Kostyanovsky, R. G.; Gella, I. M., Markov, V. I.; Samojlova, Z.
E. Tetrahedron 1974, 30, 39.
(27) Yamashita, T.; Mitsui, H.; Watanabe, H.; Nakamura, N. Bull.
Chem. Soc. J pn. 1982, 55, 961.

Chiral Tetradentate Diamine-Diamide Ligand
Organometallics, Vol. 22, No. 24, 2003 5007
1
foil, for 4 days. The mixture was cooled to room temperature
and poured into ca. 2 kg of ice. A yellow precipitate im-
mediately formed. When all of the ice was melted, the
precipitate was collected by filtration, washed thoroughly with
water, and dried under vacuum overnight (26.4 g, 98%). Anal.
Calcd for C12H16INO2S: C, 39.46; H, 4.42; N, 3.84. Found: C,
under vacuum to afford a gummy off-white solid. A H NMR
spectrum indicated that this material was C2-2 in more than
95% purity. The crude material was dissolved in a minimum
amount of hexane and cooled at -40 °C. A white solid
precipitated after 1 day. The mixture was filtered, and the
filtrate was concentrated to half of the initial volume and
stored at -40 °C to afford a second crop. The combined solids
were dried under vacuum (0.79 g, 61%). Anal. Calcd for
1
39.63; H, 4.43; N, 3.93. H NMR (CDCl3): δ 7.67 (d, J ) 8.2,
2H, o-Ph), 7.29 (d, J ) 8.2, 2H, m-Ph), 3.67 (m, 1H, CHN),
3.56 (dd, J ) 9.7 and 3.0, 1H, CHHI), 3.45 (m, 1H, CHHN),
3.18 (t, J ) 9.7, 1H, CHHI), 3.13 (m, 1H, CHHN), 2.39 (s, 3H,
CH3), 1.86-1.68 (m, 3H, CHH and CH2), 1.50-1.42 (m, 2H,
CHH). 13C NMR (CDCl3): δ 143.6 (m, i-Ph), 133.9 (m, p-Ph),
129.7 (d, J C-H ) 160, o-Ph), 127.3 (d, J C-H ) 164, m-Ph), 60.5
(d, J C-H ) 141, CHN), 49.9 (t, J C-H ) 142, CH2N), 31.8 (t, J C-H
) 132, CH2), 23.7 (t, J C-H ) 133, CH2), 21.4 (q, J C-H ) 126,
C
18H40N6Zr: C, 50.07; H, 9.34; N, 19.46. Found: C, 50.22; H,
9.10; N, 19.26. 1H NMR (C6D6): δ 4.30 (m, 2H, H-5), 3.43-
3.23 (m, 4H, H-2 and H-5), 3.23 (s, 12H, ZrN(CH3)2), 2.62 (d,
J ) 9.2, 2H, H-γ), 2.25 (q, J ) 10.3, 2H, H-R), 2.20 (dd, J )
11.0 and 4.6, 2H, H-R), 2.13 (s, 6H, NCH3), 1.85-1.75 (m, 4H,
2 H-4), 1.75-1.65 (m, 4H, H-γ + H-3), 1.05 (m, 2H, H-3). 13C
NMR (C6D6): δ 67.5 (t, J C-H ) 140), 64.3 (d, J C-H ) 133, NCH),
55.1 (t, J C-H ) 132), 53.6 (t, J C-H ) 130), 47.2 (q, J C-H ) 130,
NCH3), 45.8 (q, J C-H ) 129, N(CH3)2), 32.2 (t, J C-H ) 128),
25
CH3), 11.5 (t, J C-H ) 152, CH2I). [R]D (c 1.025, CH2Cl2) )
-154. Mp: 94-96 °C. EI-MS: 365 (M+, 0.1), 238 (5), 224 (100),
155 (45), 91 (85), 65 (15).
27.8 (t, J C-H ) 138). [R]25 (c 0.645, toluene) ) +75. EI-MS:
D
430 (M+, 1), 386 (M - NMe2, 70), 369 (10), 341 (20), 317 (45),
N,N′-Dim eth yl-N,N′-bis[(S)-2-m eth ylp yr r olid in e]eth yl-
en ed ia m in e (H2(Me2P MEN), 1). A slurry of N-tosyl-(S)-2-
(iodomethyl)pyrrolidine (32.8 g, 89.9 mmol), N,N′-dimethyl-
ethylenediamine (4.78 mL, 45.0 mmol), and anhydrous K2CO3
(31.1 g, 225 mmol) in dry acetonitrile (150 mL) was refluxed
under nitrogen, protected from light with aluminum foil, for
16 h. The mixture was cooled to room temperature and filtered.
The filtrate was concentrated under vacuum, dissolved in ethyl
acetate (150 mL), and filtered to remove remaining solid. The
filtrate was concentrated under vacuum, and residual ethyl
acetate was removed by dissolving the oil in THF (100 mL)
and further concentrating under vacuum, to afford an orange
oil (25.8 g). 1H and 13C NMR and MS analysis of this oil estab-
lished that it is a ca. 2:1 mixture of the desired bis(pyrrolidi-
nyl)ethylediamine coupling product N,N′-ditosyl-Me2PMEN
(13C{1H} NMR (CD2Cl2) δ 143.8 (i-Ph), 134.8 (p-Ph), 130.0
(o-Ph), 127.8 (m-Ph), 63.0, 59.0, 56.6, 49.4, 43.6 (NCH3), 29.8
(CH2 pyr), 24.1 (CH2 pyr), 21.4 (CH3); FAB-HRMS calcd for
248 (40), 127 (80), 44 (NMe2, 100).
(Me2P MEN)Zr Cl2 (C1-3 a n d C2-3). NMR Sca le. An NMR
tube was charged with C2-2 (20.1 mg, 0.0465 mmol) and C6D6
(ca. 0.5 mL), and then SiMe3Cl (12 µL, 0.093 mmol) was added
by syringe. The tube was shaken vigorously, and 1H NMR
spectra were recorded periodically. After 2 h at room temper-
ature, the spectrum established the presence of unreacted C2-2
(32%), an intermediate assigned as (Me2PMEN)Zr(NMe2)Cl
(36%), as well as C2-3 (27%) and C1-3 (5%). After 8 h, all the
starting material was consumed, and the solution contained
C2-3 (79%) and C1-3 (21%). Subsequently, C2-3 was progres-
sively transformed into C1-3, and the [C2-3]/[C1-3] ratio reached
a final value of 13/87 after 2 days.
P r ep a r a tive Sca le. A solution of SiMe3Cl (1.0 mL, 7.9
mmol) in benzene (10 mL) was added by cannula to a solution
of C2-2 (1.28 g, 3.00 mmol) in benzene (10 mL). The clear yellow
mixture was stirred at room temperature for 21 h, and then
pentane (50 mL) was added. A white solid formed immediately.
The solid was collected by filtration and dried under vacuum
(0.48 g, 39%). 1H NMR analysis established that this material
was pure 3, as a 38/62 mixture of C1 and C2 isomers. The
filtrate was concentrated under vacuum to give a yellow oil,
which was dissolved in toluene (1 mL). Crystallization of this
solution at -30 °C (3 days) afforded pale yellow crystals of
pure C1-3, which proved to be suitable for X-ray crystal-
lography (0.28 g, 22%). Combined yield: 0.76 g, 61%. Anal.
Calcd for C14H28N4Cl2Zr: C, 40.56; H, 6.81; N, 13.52. Found:
C, 40.88; H, 6.88; N, 13.11. C2-3: 1H NMR (C6D6): δ 4.75 (ddd,
J ) 11.3, 8.2, and 2.8, 2H, H-5), 3.32-3.22 (m, 4H, H-2 and
H-5), 2.93 (d, J ) 10.1, 2H, H-γ), 2.78 (t, J ) 11.1, 2H, H-R),
2.34 (s, 6H, NCH3), 2.35 (m, 2H, H-R), 1.95 (d, J ) 9.4, 2H,
H-γ), 1.85 (m, 2H), 1.65-1.53 (m, 4H), 1.15 (m, 2H). 13C NMR
(C6D6): δ 65.2 (t, J C-H ) 138), 64.6 (d, J C-H ) 135, NCH), 54.4
(t, J C-H ) 137), 54.3 (t, J C-H ) 137), 47.6 (q, J C-H ) 138,
NCH3), 30.8, 26.6 (t, J C-H ) 129). C1-3: 1H NMR (C6D6): δ
4.50 (ddd, J ) 3.8, 7.6, and 11.7, 1H, H-5), 4.08 (ddd, J ) 3.4,
8.3, and 11.3, 1H, H-5), 3.80-3.65 (m, 2H), 3.30 (m, 1H), 3.10
(m, 1H), 2.57 (s, 3H, NCH3), 2.65-2.50 (m, 3H), 2.46 (s, 3H,
NCH3), 2.46 (m, 1H), 2.40-2.30 (m, 2H), 2.26 (dd, J ) 3.9 and
11.1, 1H, H-R), 2.10-1.90 (m, 2H), 1.71 (m, 1H), 1.65-1.40
(m, 4H), 1.02-0.90 (m, 2H). 1H NMR (CD2Cl2): δ 4.21 (m, 1H),
4.03 (m, 1H), 3.94 (m, 1H), 3.68 (m, 1H), 3.61 (m, 1H), 3.28
(m, 1H), 3.18-2.84 (m, 5H), 2.79 (s, 3H, NCH3), 2.69 (s, 3H,
NCH3), 2.60 (m, 1H), 1.89-1.70 (m, 8H), 1.19-1.09 (m, 2H).
13C NMR (C6D6): δ 69.1 (t, J C-H ) 136), 67.3 (t, J C-H ) 136),
66.2 (d, J C-H ) 138, NCH), 64.6 (d, J C-H ) 133, NCH), 60.6 (t,
J C-H ) 137), 58.0 (t, J C-H ) 138), 56.2 (t, J C-H ) 140), 54.1 (t,
J C-H ) 136), 53.2 (q, J C-H ) 138, NCH3), 45.5 (q, J C-H ) 137,
N′CH3), 32.0 (t, J C-H ) 130), 30.9 (t, J C-H ) 130), 27.6 (t, J C-H
) 130), 27.0 (t, J C-H ) 131). EI-MS: 412 (M+, 7), 377 (M - Cl,
3), 330 (30), 274 (17), 160 (17), 127 (64), 84 (73), 70 (93), 58
(100).
C
28H43N4O4S2 (MH+), 563.2725; found, 563.2710; EI-MS 338
(M - PyrTos, 80), 281 (M/2, 100), 238 (PyrTos, 30), 155 (50),
91 (95)) and the mono(pyrrolidinyl)ethylenediamine coupling
product 2-(C4H8N)CH2N(Me)CH2CH2NHMe (FAB-MS 326
(MH+); EI-MS 281 (M - CH2NHMe, 30), 238 (15), 155 (35),
101 (M - PyrTos, 100), 91 (85)).
This crude oil was dissolved in dry 1,2-dimethoxyethane
(DME, 75 mL) and added under nitrogen over 1.5 h to a
refluxing slurry of LiAlH4 (25.3 g, 668 mmol) in DME (150
mL). The reaction mixture was refluxed for 24 h, cooled to room
temperature, and carefully hydrolyzed (ice bath) with 3 N
NaOH until H2 evolution ceased. The resulting gel was filtered
on a frit and washed with toluene (200 mL), THF (200 mL),
and finally hexane (200 mL). The filtrate was concentrated
under vacuum to give a yellow oil, which was dissolved in
diethyl ether (50 mL) and dried overnight over KOH pellets.
After filtration and removal of ether, the oil was distilled under
vacuum (0.05 mmHg). The second fraction (bp 100 °C) was
collected and redistilled to afford pure 1 as a colorless oil,
which rapidly became pale yellow in air (5.27 g, 40% based on
N-tosyl-(S)-2-(iodomethyl)pyrrolidine). Anal. Calcd for
C
14H30N4: C, 66.09; H, 11.89; N, 22.02. Found: C, 66.33; H,
11.85; N, 21.83. 1H NMR (CDCl3): δ 3.20 (m, 2H), 3.0 (s br,
2H, NH), 2.90 (m, 2H), 2.80 (m, 2H), 2.45 (m, 2H), 2.40-2.35
(m, 4H), 2.18 (s, 6H, NCH3), 2.17 (m, 2H), 1.77 (m, 2H), 1.68-
1.56 (m, 4H), 1.22 (m, 2H). 13C NMR (CDCl3): δ 63.3 (t, J C-H
) 128), 55.8 (d, J C-H ) 133, NCH), 55.8 (t, J C-H ) 134), 45.7
(t, J C-H ) 136), 43.0 (q, J C-H ) 133, NCH3), 29.5 (t, J C-H
)
132, CH2 pyr), 24.7 (t, J C-H ) 128, CH2 pyr). [R]25 (c 0.78,
D
CHCl3) ) +23. EI-MS: 205 (2), 184 (3), 160 (20), 127 (85), 116
(25), 84 (90), 70 (pyr, 75), 58 (100).
(Me2P MEN)Zr (NMe2)2 (C2-2). Compound 1 (0.767 g, 3.02
mmol) was added to a solution of Zr(NMe2)4 (0.807 g, 3.02
mmol) in benzene (10 mL). The reaction mixture was stirred
at room temperature for 3 h, and the volatiles were removed

5008 Organometallics, Vol. 22, No. 24, 2003
Carpentier et al.
(Me2P MEN)Zr Me2 (C2-4). Neat SiMe3Cl (0.300 mL, 2.38
mmol) was added by syringe to a solution of C2-2 (0.490 g, 1.13
mmol) in benzene (7 mL). The mixture was stirred at room
temperature for 5 days. The volatiles were removed under
vacuum to yield a yellow solid, which was dried under vacuum
for 3 h. This material was dissolved in toluene (20 mL), and
MeLi (1.4 M in Et2O, 1.7 mL, 2.4 mmol) was added at room
temperature over a period of 3 min. The yellow slurry was
stirred for 5 h and filtered through a pad of Celite, which was
then washed with toluene (10 mL). The combined filtrate and
wash was concentrated under vacuum to yield a yellow-brown
1H), 1.70-1.55 (m, 4H), 1.55-1.40 (m, 3H), 1.32 (m, 1H), 1.12
(d, J ) 9.0, 1H), 1.05 (m, 1H), 0.87 (m, 1H). 13C NMR (C6D6):
δ 154.4 (s, i-Ph), 148.7 (s, i-Ph), 127.9, 127.4, 126.2, 119.3 (d,
J C-H ) 159, p-Ph), 118.9 (d, J C-H ) 158, p-Ph), 70.0 (t, J C-H
)
133), 67.0 (t, J C-H ) 132), 66.8 (d, J C-H ) 136, NCH), 66.4 (t,
J C-H ) 122), 64.8 (d, J C-H ) 128, NCH), 60.3 (t, J C-H ) 117),
59.0 (t, J C-H ) 117), 58.9 (t, J C-H ) 117), 53.8 (t, J C-H ) 138),
52.2 (t, J C-H ) 136), 52.1 (q, J C-H ) 137, NCH3), 43.3 (q, J C-H
) 135, NCH3), 31.1 (t, J C-H ) 131), 31.0 (t, J C-H ) 132), 27.6
(t, J C-H ) 131), 27.2 (t, J C-H ) 137).
(Me2P MEN)Ti(CH2P h )2 (C2-6). H2(Me2PMEN) (1) (0.400
g, 1.57 mmol) was added to a stirred solution of Ti(CH2Ph)4
(0.650 g, 1.57 mmol) in toluene (10 mL). A red precipitate
formed immediately. Stirring was continued for 4 h at room
temperature. The mixture was then concentrated under
vacuum to ca. 2 mL, and pentane (20 mL) was added. The
resulting precipitate was collected by filtration, washed with
pentane, and dried under vacuum overnight to give a brick
red powder (0.65 g, 85%). Crystals for X-ray diffraction were
obtained by crystallization from toluene at -30 °C. Anal. Calcd
for C28H42N4Ti: C, 69.69; H, 8.77; N, 11.61. Found: C, 69.34;
H, 8.68; N, 11.52. EI-MS: 427 (3), 391 (M+ - CH2Ph, 6), 319
1
solid. A H NMR spectrum indicated that this material was
C2-4 in more than 95% purity. This material was recrystallized
from pentane at -40 °C (3 days), affording C2-4 as colorless
crystals (0.283 g, 67%). Anal. Calcd for C16H34N4Zr: C, 51.43;
H, 9.17; N, 14.99. Found: C, 50.64; H, 9.29; N, 14.13.28 1H
NMR (C6D6): δ 4.61 (ddd, J ) 10.8, 8.2, and 2.8, 2H, H-5),
3.41-3.34 (m, 4H, H-2 and H-5), 2.78 (d, J ) 9.4, 2H, H-γ),
2.43 (t, J ) 10.9, 2H, H-R), 2.16 (dd, J ) 10.9 and 4.2, 2H,
H-R), 2.01 (m, 2H, H-4), 1.93 (s, 6H, NCH3), 1.80-1.66 (m, 4H,
H-3 and H-4), 1.23 (d, J ) 9.4, 2H, H-γ), 1.23 (m, 2H, H-3),
0.39 (s, 6H, ZrCH3). 13C NMR (C6D6): δ 64.9 (d, J C-H ) 133),
64.7 (t, J C-H ) 131), 53.0 (t, J C-H ) 132), 52.2 (t, J C-H ) 129),
45.2 (q, J C-H ) 135, NCH3), 35.1 (q, J C-H ) 100, ZrCH3), 31.4
(t, J C-H ) 128), 27.4 (t, J C-H ) 130). EI-MS: 357 (M+ - CH3,
85), 339 (85), 288 (39), 272 (100). [R]25D (c 0.47, toluene) ) +85.
(Me2P MEN)Zr (CH2P h )2 (C1-5 a n d C2-5). NMR Sca le. A
Teflon-valved NMR tube was charged with Zr(CH2Ph)4 (90.0
mg, 0.197 mmol) and C6D6 (ca. 1 mL), and 1 (50.0 mg, 0.197
mmol) was added. The tube was shaken vigorously, and a clear
yellow solution formed. A 1H NMR spectrum was recorded
after 15 min and revealed complete conversion to 5 as a 85/15
mixture of C1-5 and C2-5. The tube was allowed to stand at
room temperature, and 1H NMR spectra were periodically
recorded. After 5 days, the [C1-5]/[C2-5] ratio reached a
constant value of 15/85.
1
(6), 299 (11), 250 (3), 230 (8), 91 (100). H NMR (CD2Cl2): δ
7.01 (t, J ) 7.6, 4H, m-Ph), 6.92 (d, J ) 6.8, 4H, o-Ph), 6.66 (t,
J ) 7.2, 2H, p-Ph), 4.59 (ddd, J ≈ 13, 8, and 4, 2H, H-5), 3.85
(m, 2H, H-2), 3.55 (m, 2H, H-5), 3.26 (d, J ) 9.0, 2H, H-γ),
2.61 (t, J ) 10.6, 2H, H-R), 2.51 (dd, J ) 4.5 and 15.8, 2H,
H-R), 2.33 (d, J ) 10.1, 2H, CHHPh), 2.26 (s, 6H, NCH3), 2.09
(d, J ) 10.1, 2H, CHHPh), 2.02 (d, J ) 8.7, 2H, H-γ), 1.56-
1
1.43 (m, 4H, H-4), 1.37 (m, 2H, H-3), 0.23 (ddd, 2H, H-3). H
NMR (C6D6, low solubility): δ 7.28 (t, J ) 7.9, 4H, m-Ph), 7.20
(d, overlap with solvent, 4H, o-Ph), 6.97 (t, J ) 6.8, 2H, p-Ph),
4.83 (ddd, J ≈ 13, 9, and 5, 2H, H-5), 3.64-3.52 (m, 4H, H-2
and H-5), 2.62-2.50 (m, 8H, H-R + H-γ + others), 2.02 (dd, J
) 11.2 and 4.3, 2H, H-R), 1.81 (s, 6H, NCH3), 1.61 (m, 2H),
1.43 (m, 2H), 1.16 (d, J ) 9.0, 2H, H-γ), 0.45 (m, 2H, H-3). 13
C
NMR (CD2Cl2): δ 157.4 (s, i-Ph), 127.7 (d, J C-H ) 155, Ph),
125.4 (d, J C-H ) 155, Ph), 119.2 (d, J C-H ) 158, p-Ph), 81.9 (t,
J C-H ) 120, CH2Ph), 67.9 (d, J C-H ) 130, NCH), 62.3 (t, J C-H
) 136), 54.9 (t, J C-H ) 129), 53.5 (t, J C-H ) 136), 46.5 (q, J C-H
) 136, NCH3), 29.2 (t, J C-H ) 130), 26.6 (t, J C-H ) 130).
13C{1H} NMR (C6D6, low solubility): δ 157.3 (i-Ph), 127.9 (Ph),
125.8 (Ph), 119.8 (p-Ph), 83.7 (CH2Ph), 67.6 (NCH), 62.0, 55.0,
52.8, 45.9 (NCH3), 29.2, 26.8. [R]25D (c 0.42, toluene) ) -3733.
P r ep a r a tive Sca le. A solution of 1 (0.400 g, 1.57 mmol)
in toluene (10 mL) was added by cannula to a solution of
Zr(CH2Ph)4 (0.720 g, 1.57 mmol) in toluene (10 mL) in a
Schlenk tube. The tube was protected from light with alumi-
num foil, and the clear yellow solution was stirred at room
temperature for 2 h. Toluene was removed under vacuum to
give a yellow oil, which was dried for 3 h. Pentane (10 mL)
was added, which resulted in the immediate precipitation of
an off-white solid, which was triturated, collected by filtration,
and dried under vacuum overnight (0.63 g, 76%). 1H NMR
analysis established that this material was pure 5 as a 77/23
mixture of C1 and C2 isomers. Anal. Calcd for C28H42N4Zr: C,
63.95; H, 8.05; N, 10.65. Found: C, 63.58; H, 8.41; N, 10.44.
EI-MS: 433 (M+ - CH2Ph, 40), 339 (25), 272 (25), 91 (100).
C2-5: 1H NMR (C6D6): δ 7.20-7.08 (m, 8H, Ph), 6.85 (t, J )
7.6, 2H, p-Ph), 4.35 (ddd, J ) 11.3, 8.4 and 3.2, 2H, H-5), 3.30-
3.15 (m, 4H, H-2 and H-5), 2.61 (d, J ) 9.7, 2H, H-γ), 2.45 (d,
J ) 10.1, 2H, CHHPh), 2.26 (t, J ) 10.8, 2H, H-R), 2.11 (d, J
) 10.1, 2H, CHHPh), 1.95 (m, 2H, H-R), 1.83 (s, 6H, NCH3),
1.79 (m, 2H), 1.60 (m, 2H), 1.45 (m, 2H), 1.10 (d, J ) 9.4, 2H,
H-γ), 0.70 (m, 2H). 13C NMR (C6D6): δ 152.4 (s, i-Ph), 128.3
(d, J C-H ) 155, CH Ph), 126.3 (d, J C-H ) 153, CH Ph), 119.7
(d, J C-H ) 158, p-Ph), 67.1 (t, J C-H ) 117, CH2Ph), 65.1 (d,
J C-H ) 129, NCH), 63.4 (t, J C-H ) 135), 53.2 (t, J C-H ) 137),
52.5 (t, J C-H ) 137), 44.9 (q, J C-H ) 136, NCH3), 30.2 (t, J C-H
) 128), 27.1 (t, J C-H ) 127). C1-5: 1H NMR (C6D6): δ 7.42-
7.32 (m, 2H, Ph), 7.20-7.05 (m, 6H, Ph), 6.98 (m, 1H, p-Ph),
6.90 (m, 1H, p-Ph), 3.92 (ddd, J ) 11.5, 8.0, and 3.6, 1H, H-5),
3.85 (ddd, J ) 11.5, 8.6, and 3.6, 1H, H-5), 3.50 (m, 1H), 3.08
(m, 1H), 2.96 (m, 1H), 2.88 (m, 1H), 2.66 (d, J ) 9.4, 1H, H-γ),
2.20-2.12 (m, 2H), 2.10 (d, J ) 9.0, 1H, H-γ), 2.02-1.93 (m,
4H), 1.96 (s, 3H, NCH3), 1.94 (s, 3H, NCH3), 1.70 (d, J ) 10.4,
(Me2P MEN)TiMe2 (C2-7). A flask was charged with Ti(CH2-
Ph)4 (0.325 g, 0.790 mmol) and toluene (20 mL), and 1 (0.200
g, 0.790 mmol) was added dropwise at room temperature. The
mixture was stirred for 4 h, at which point the 1H NMR
spectrum of an aliquot (C6D6) revealed total conversion to
(Me2PMEN)Ti(CH2Ph)2 (6). The mixture was cooled to -78 °C,
and a solution of I2 (0.400 g, 1.57 mmol) in toluene (10 mL)
was added by cannula. A brown precipitate immediately
formed. The mixture was warmed to room temperature and
stirred for 3 h. The volatiles were removed under vacuum to
leave a dark brown oily solid, which was dried under vacuum
overnight. The residue was dissolved in CH2Cl2 (10 mL), and
hexanes (10 mL) were added. An orange-brown solid im-
mediately formed and was isolated by removing the superna-
tant by cannula. The solid was dried under vacuum overnight
(“(Me2PMEN)TiI2”, 0.34 g, 78%; EI-MS: 427 (M+ - I, 30), 358
(6), 128 (100), 84 (45), 70 (55)). A portion of this solid (0.27 g,
0.49 mmol) was slurried in Et2O (40 mL) and cooled to -78
°C, and MeMgCl (0.33 mL, 3.0 M in Et2O, 0.98 mmol) was
added by syringe. The mixture was warmed to room temper-
ature and stirred for 7 h. A clear orange solution formed.
Dioxane (0.2 mL, 2.3 mmol) was added by syringe, resulting
in the immediate formation of a precipitate. The mixture was
filtered, and the volatiles were removed under vacuum to leave
a red gummy solid, which was dried overnight (0.080 g, 49%).
NMR analysis indicated that this material is ca. 90% pure
(Me2PMEN)TiMe2. This material is thermally unstable as
(28) Low C and N analyses for C2-4 and 8 were consistently obtained
for spectroscopically pure samples.

Chiral Tetradentate Diamine-Diamide Ligand
Organometallics, Vol. 22, No. 24, 2003 5009
described in the text. EI-MS: 315 (M+ - CH3, 40), 297 (45),
CHHPh) and 2.05 (d, 1H, J ) 9.3, CHHPh). 13C NMR (25 °C):
δ 146.8 (s, i-Ph), 122.5 (d, J C-H ) 153, p-Ph), 74.9 (t, J C-H )
1
230 (35), 228 (40), 127 (82), 58 (100). H NMR (C6D6): δ 5.04
(ddd, J ) 4.0, 7.9, and 11.9, 2H, H-5), 3.80-3.65 (m, 4H, H-2
and H-5), 2.73 (d, J ) 9.0, 2H, H-γ), 2.50 (t, J ) 10.4, 2H,
H-R), 2.20-2.10 (m, 6H), 1.85-1.75 (m, 4H), 1.78 (s, 6H,
NCH3), 1.20 (d, J ) 9.0, 2H, H-γ), 0.81 (s, 6H, TiCH3). 13C NMR
(C6D6): δ 67.4 (d, J C-H ) 131, NCH), 63.4 (t, J C-H ) 135), 55.0
(t, J C-H ) 131), 52.3 (t, J C-H ) 132), 47.9 (q, J C-H ) 116,
TiCH3), 45.7 (q, J C-H ) 137, NCH3), 31.2 (t, J C-H ) 129), 27.4
(t, J C-H ) 129).
127, CH2Ph), 65.6 (br), 64.1 (br), 62.4 (br), 60.5 (br), 57.5 (br),
55.0 (br), 54.5 (t, J C-H ) 140), 46.6 (br), 43.7 (br), 30.4 (br),
25.9 (t, J C-H ) 133). Resonances for B(C6F5)4 were also
observed: δ 147.8 (d, J C-F ) 241), 138.0 (d, J C-F ) 249), 135.7
(d, J C-F ) 251), Cipso not observed.
-
[(Me2P ME N)Zr (CH2P h )][B(C6F 5)4] (9). P r ep a r a t ive
Sca le. Benzene (10 mL) was added to a mixture of 5 (0.118 g,
0.224 mmol) and [HNMe2Ph][B(C6F5)4] (0.179 g, 0.224 mmol),
and the mixture was stirred at room temperature for 15 min.
An orange oil separated. The yellow upper layer was removed
with a pipet, benzene (5 mL) was added, and the mixture was
stirred for 5 min. The upper benzene layer was removed with
a pipet, pentane (5 mL) was added, and the mixture was
stirred for 5 min. The supernatant was decanted off, and the
solid was dried under vacuum to yield a pale orange solid
(0.230 g, 92%). Anal. Calcd for C45H35N4BF20Zr: C, 48.53; H,
3.17; N, 5.03. Found: C, 48.38; H, 3.39; N, 4.69. 1H NMR
(CD2Cl2, -40 °C) (assignments were made on the basis of a
COSY and a 13C-detected 13C-1H HETCOR experiment at -40
°C): δ 7.37 (t, J ) 7.2, 2H, m-Ph), 7.06 (t, J ) 7.2, 1H, p-Ph),
6.82 (d, J ) 7.2, 2H, o-Ph), 4.02-3.87 (m, 2H, H-5 and H′-5),
3.84 (m, 1H, H-2), 3.70 (m, 1H, H′-2), 3.38-3.25 (m, 2H, H-5
and H-γ), 3.15 (m, 1H, H′-5), 3.00 (dd, J ) 4.1 and 12.4, 1H,
H-R), 2.73 (d, J ) 8.3, 1H, CHHPh), 2.80-2.60 (m, 5H, 3H-R
and 2H-γ), 2.57 (s, 3H, NCH3), 2.17 (d, J ) 8.3, 1H, CHHPh),
2.12 (dd, J ) 2.7 and 14.2, 1H, H-γ), 1.90-1.70 (m, 6H, 4H-4
+ H-3 + H′-3), 1.76 (s, 3H, N′CH3), 1.25-1.05 (m, 2H, H-3
and H′-3). 13C NMR (CD2Cl2, -80 °C): δ 142.3 (s, i-Ph), 133.0
(d, J C-H ≈ 160, m-Ph), 124.8 (d, J C-H ) 157, p-Ph), 119.6 (d,
(Me2P MEN)Ti(NMe2)2. Neat H2(Me2PMEN) (1) (0.200 g,
0.786 mmol) was added to a solution of Ti(NMe2)4 (0.176 g,
0.786 mmol) in toluene (4 mL). The reaction mixture was
stirred at room temperature for 18 h, and the volatiles were
removed under vacuum to leave a red oil. A 1H NMR spec-
trum indicated that this material contained ca. 30% of
C2-(Me2PMEN)Ti(NMe2)2 along with unidentified products.
The crude material was dissolved in a minimum amount of
pentane and cooled at -40 °C. After 2 months, a small amount
of red crystals was recovered by filtration (10 mg) and
1
identified as C2-(Me2PMEN)Ti(NMe2)2 by H NMR (C6D6): δ
4.44 (m, J ) 8.9, 2H, H-5), 3.46 (s, 12H, Ti-N(CH3)2), 3.30-
3.20 (m, 4H), 2.47 (d, J ) 9.0, 2H, H-γ), 2.33 (t, J ) 10.9, 2H,
H-R), 2.17 (dd, J ) 11.1 and 4.6, 2H, H-R), 2.12 (s, 6H, N-CH3),
2.03 (d, J ) 8.7, 2H, H-γ), 1.85-1.60 (m, 6H, H-4 + H-3), 1.20-
1.10 (m, 2H, H-3).
[(Me2P MEN)Ti(CH2P h )][B(C6F 5)4] (8). P r ep a r a tive
Sca le. Benzene (10 mL) was added to a mixture of C2-6 (0.150
g, 0.311 mmol) and [HNMe2Ph][B(C6F5)4] (0.249 g, 0.311
mmol). An orange-red oil separated immediately. The mixture
was stirred at room temperature for 15 min. The yellow upper
layer was removed with a pipet, benzene (10 mL) was added
to the remaining oil, and the mixture was stirred for 5 min.
The upper benzene layer was removed with a pipet. This
procedure was repeated twice. The final oily lower phase was
dried under vacuum. The resulting brown residue was tritu-
rated with pentane (5 mL) to leave an orange-brown powder,
which was collected by filtration, washed with pentane, and
dried under vacuum overnight (0.284 g, 85%). Anal. Calcd for
J C-H ) 152, o-Ph), 64.3 (t, J C-H ) 135, NCH2), 63.5 (t, J C-H
)
136, N′CH2), 61.8 (d, J C-H ) 144, NCH), 61.0 (d, J C-H ) 137,
N′CH), 60.7 (t, J C-H ) 138, CH2Ph), 56.2 (t, J C-H ) 136), 50.9
(t, J C-H ) 139), 49.9 (t, J C-H ) 138), 47.1 (q, J C-H ) 138,
NCH3), 42.7 (q, J C-H ) 138, N′CH3), 30.1 (t, J C-H ) 131), 29.6
(t, J C-H ) 131), 27.2 (t, J C-H ) 131), 26.2 (t, J C-H ) 132); one
resonance is obscured by the solvent signals. Resonances for
-
B(C6F5)4 were also observed: δ 147.2 (d, J C-F ) 240), 137.4
C
45H35N4BF20Ti: C, 50.49; H, 3.30; N, 5.23. Found: C, 48.92;
(d, J C-F ) 243), 135.5 (d, J C-F ) 243), 123.0 (m br). 19F NMR
H, 2.89; N, 5.02.28 1H NMR (CD2Cl2, 233 K): δ 7.20 (t, J )
7.9, 2H, m-Ph), 6.83 (t, J ) 7.2, 1H, p-Ph), 6.77 (d, J ) 7.6,
2H, o-Ph), 4.18 (m, 1H), 4.09 (m, 1H), 4.00 (m, 1H), 3.77 (dd,
J ) 8.1 and 13.4, 1H), 3.70 (m, 1H), 3.67-3.55 (m, 2H), 3.50-
3.42 (m, 2H), 3.29 (d, J ) 9.0, 1H, CHHPh), 3.18 (m, 1H), 2.91
(d, J ) 9.4, 1H), 2.85 (dd, J ) 2.7 and 13.6, 1H), 2.74 (m, 1H),
2.70 (s, 3H, NCH3), 2.67-2.57 (m, 2H), 2.31 (s, 3H, N′CH3),
2.03 (d, J ) 9.0, 1H, CHHPh), 2.00-1.89 (m, 2H), 1.87-1.45
(m, 5H). 13C NMR (CD2Cl2, 213 K): δ 146.8 (s, i-Ph), 128.1 (d,
J C-H ) 157), 126.5 (d, J C-H ) 157), 121.5 (d, J C-H ) 153, p-Ph),
73.4 (t, J C-H ) 127, CH2Ph), 65.6 (d, J C-H ) 144, NCH), 63.2
(t, J C-H ) 140), 62.7 (t, J C-H ) 140), 60.4 (d, J C-H ) 139, N′CH),
57.5 (t, J C-H ) 139), 55.0 (t, J C-H ) 137), 54.5 (overlap with
solvent), 54.2 (t, J C-H ) 140), 46.6 (q, J C-H ) 138, NCH3), 44.3
(CD2Cl2): δ -132.5 (d, J F-F ) 11.0, 2F, o-F), -163.1 (t, J F-F
)
20.5, 1F, p-F), -167.0 (t, J F-F ) 18, 2F, m-F). 11B NMR (CD2-
Cl2, 193 K): δ -15.6 (s).
Gen er a tion
of
[(Me2P MEN)Zr (CH3)(THF -d 8)]-
[B(C6F 5)4] (10). A NMR tube was charged with 5 (29 mg, 0.078
mmol) and [HNMePh2][B(C6F5)4] (67 mg, 0.078 mmol). THF-
d8 was vacuum transferred in at -80 °C, and the tube was
allowed to warm to room temperature. Vigorous gas evolution
was observed. A 1H NMR analysis of the resulting yellow
solution after 15 min established the presence of methane (δ
0.17), free NMePh2 (δ 7.20 (tm, J ) 7.6, 4H, m-H), 6.98 (dd, J
) 7.6 and 1.1, 4H, o-H), 6.87 (tt, J ) 7.3 and 1.1, 2H, p-H),
3.27 (s, 3H, NCH3)), and three zirconium complexes, of which
the major one has C2-symmetry (key data: δ 2.54 (s, 6H,
NCH3), 0.08 (s, 3H, ZrCH3)). After 4 days at room temperature,
only one C1-symmetric species, assigned as 10, was observed.
1H NMR (THF-d8): δ 4.07 (td, J ) 10.8 and 6.3, 1H), 3.97 (m,
1H), 3.84 (ddd, J ) 10.7, 7.6, and 2.7, 1H), 3.66 (m, 1H), 3.47-
3.34 (m, 2H), 3.19 (dd, J ) 12.3 and 4.5, 1H), 3.12-3.02 (m,
2H), 2.84 (m, 1H), 2.78 (t, J ) 4.9, 1H), 2.74 (s, 3H, NCH3),
2.72 (s, 3H, N′CH3), 1.80-1.70 (m, 9H), 1.23-1.13 (m, 2H),
(q, J C-H ) 137, N′CH3), 30.5 (t, J C-H ) 132), 30.4 (t, J C-H
)
132), 25.9 (t, J C-H ) 133), 25.8 (t, J C-H ) 133). Resonances for
-
B(C6F5)4 were also observed: δ 147.4 (d, J C-F ) 241), 137.7
(d, J C-F ) 239), 135.7 (d, J C-F ) 243), 123.0 (m br). 19F NMR
(CD2Cl2): δ -132.5 (d, J F-F ) 11.0, 2F, o-F), -163.1 (t, J F-F
)
20.5, 1F, p-F), -167.0 (t, J F-F ) 18, 2F, m-F). 11B NMR
(CD2Cl2): δ -15.0 (s).
NMR Sca le Gen er a tion of 8 fr om C2-6 a n d [P h 3C]-
[B(C6F 5)4]. An NMR tube was charged with C2-6 (50.0 mg,
0.103 mmol) and [Ph3C][B(C6F5)4] (96.0 mg, 0.103 mmol).
Chlorobenzene-d5 was vacuum transferred in at -80 °C, and
the tube was allowed to warm to room temperature. The
resulting yellow solution was immediately analyzed by NMR,
which established the formation of Ph3CCH2Ph (1H NMR δ
3.95 (s, 2H, Ph3CCH2Ph); 13C NMR δ 46.2 (t, J ) 128,
-0.22 (s, 3H, ZrCH3). 13C NMR (THF-d8): δ 67.2 (t, J C-H
)
135), 66.7 (t, J C-H ) 136), 64.7 (d, J C-H ) 139, NCH), 64.2 (d,
J C-H ) 139, N′CH), 59.5 (t, J C-H ) 137), 55.7 (t, J C-H ) 136),
53.7 (t, J C-H ) 136), 52.2 (t, J C-H ) 136), 49.1 (q, J C-H ) 137,
NCH3), 45.3 (q, J C-H ) 137, N′CH3), 33.7 (q, J C-H ) 110,
ZrCH3), 31.6 (t, J C-H ) 131), 30.9 (t, J C-H ) 128), 28.0 (t, J C-H
) 131), 27.6 (t, J C-H ) 130). Resonances for free NMePh2 (δ
129.8 (dm, J C-H ) 155), 121.9 (dt, J C-H ) 159), 121.2 (dm, J C-H
) 157), Cipso not observed, 40.4 (q, J C-H ) 135, NCH3)) and
1
1
Ph3CCH2Ph)). H NMR (25 °C): Most of the H NMR signals
for 8 were broad at 25 °C except: δ 2.75 (d, 1H, J ) 9.3,

5010 Organometallics, Vol. 22, No. 24, 2003
Carpentier et al.
Ta ble 6. Su m m a r y of Cr ysta l Da ta for Com p ou n d s
parameters of the atoms of this ring. Additionally, because of
near coincidence (C13-C13′ ) 0.270 Å), the thermal param-
eters for C13 and C13′ were constrained to be the same. The
thermal parameters of C14 and C14′ were restrained to be
similar due to their close proximity (C14-C14′ ) 0.681 Å). All
non-hydrogen atoms were refined with anisotropic thermal
parameters. All hydrogen atoms were included with the riding
model using program default values.
A red hexagonal plate of C2-6 was selected, and a total of
7497 data were collected using θ/2θ scans. Based on prelimi-
nary examination of the crystal, the space group P61 was
assigned. Intensity standards were measured at 2 h intervals
and showed no decay. Lorentz and polarization corrections and
an empirical absorption correction based on three æ scans
measured at 10° intervals were applied. The rigid bond
restraint was imposed on the anisotropic thermal parameters
of the ligand atoms. The crystal is merohedrally twinned (twin
law ) 0 1 0, 1 0 0, 0 0 -1) and the fraction of twinning refined
to 0.470(2). All non-hydrogen atoms were refined with aniso-
tropic thermal parameters. All hydrogen atoms were included
with the riding model using program default values.
C1-3 a n d C2-6
C1-3
C2-6
formula
cryst syst
space group
a (Å)
C
14H28Cl2N4Zr
C28H42N4Ti
hexagonal
P61
8.436(2)
8.436(2)
65.57(2)
4041(1)
6
orthorombic
P212121
12.739(4)
15.984(6)
8.960(3)
1824(1)
b (Å)
c (Å)
V (Å3)
Z
4
Dc (g cm-3
)
1.509
0.895
1.190
0.339
µ (mm-1
)
cryst size (mm)
cryst color, habit
T (K)
0.39 × 0.09 × 0.08
pale yellow needle
213
0.13 × 0.13 × 0.09
red block
213
diffractometer
radiation, λ (Å)
F(000)
Enraf-Nonius CAD4 Enraf-Nonius CAD4
Mo KR, 0.710 73
Mo KR, 0.710 73
1560
856
θ range (deg)
2.0-25.0
2.0-25.0
data collected: h;k;l (15; -1,18; -10,3
-1,10; -10,4;
-77,53
no. of reflns
3870
7497
Eth ylen e P olym er iza tion . Polymerization experiments
were performed in a 250 mL Fischer-Porter bottle equipped
with a magnetic stirring bar and externally heated with an
oil bath as desired. In a typical experiment (Table 5, entry 3),
the Fischer-Porter bottle was charged with the activator
[Ph3C][B(C6F5)4] (40 mg, 43 µmol) and placed under 1 atm of
ethylene (99.99%). A solution of 5 (25 mg, 48 µmol) in toluene
(13 mL) was introduced via cannula. The ethylene pressure
was increased to 1.4 atm (20 psi, maintained constant during
the experiment), and the solution was stirred for 1.5 h.
Ethylene was vented, the Fischer-Porter bottle was opened
to air, and 5% solution of HCl in ethanol (60 mL) was added.
The mixture was stirred for 30 min. The polymer was collected
by filtration, washed with 5% aqueous HCl (60 mL) and
acetone (2 × 10 mL), and dried under vacuum overnight (0.495
g; activity ) 5430 g PE/mol of activated Zr‚h‚atm). Gel
permeation chromatography (GPC) analyses were performed
on a Waters 150C chromatograph equipped with differential
refractometer and viscometer detectors using a PL gel mixed-
bed column, and at 145 °C in 1,2,4-trichlorobenzene. DSC
analyses were conducted on a Perkin-Elmer DSC-2 model
calibrated using indium metal with a sweep rate of 10 °C/min
from 25 to 200 °C.
no. of indep reflns
2882 (0.0922)
3089 (0.1158)
(Rint
)
no. of obsd reflns
(I > 2σ(I))
2021
1861
structure solution
direct methodsa
1.032
0.0483
0.0834
0.42
direct methodsa
0.998
0.0535
0.0846
0.22
GOF on F2
R1 (I > 2σ(I))b
c
wR2
max. resid density
(e Å-3
)
a
SHELXTL-Plus Version 5, Siemens Industrial Automation,
b
2
Inc., Madison, WI. R1 ) ∑||Fo| - |Fc||/∑|Fo|. c wR2 ) [∑[w(Fo
-
Fc2)2]/∑[w(Fo2)2]]1/2, where w ) [σ2(Fo2) + (aP)2 + bP]-1
.
B(C6F5)4- (δ 149.1 (d, J C-F ) 226), 139.2 (d, J C-F ) 229), 137.1
(d, J C-F ) 243), 125.0 (m br)) were also observed.
X-r a y Str u ctu r a l Deter m in a tion s. Data collection, solu-
tion, and refinement procedures and parameters are sum-
marized in Table 6, and details are provided in the Supporting
Information. The data processing, solution, and refinement
were done using SHELXTL v5.0 programs.
A pale yellow needle of C1-3 was selected, and a total of 3870
data were collected using θ/2θ scans. On the basis of prelimi-
nary examination of the crystal, the space group P212121 was
assigned. Intensity standards were measured at 2 h intervals
and showed no decay. Lorentz and polarization corrections,
as well as a Gaussian absorption correction based on crystal
dimensions, were applied. The C12-C13-C14-C15-N16 ring
has two conformations; C12, C15, and N16 are common to
both. Two positions of partial occupancy were included for C13
and C14 (C13′ and C14′ are the alternate sites; occupancy
fraction ) 0.46(2) for C13 and C14, occupancy fraction )
0.54(2) for C13′ and C14′). The C12-C13, C13-C14, and
C14-C15 distances were restrained to be the same as the
C12′-C13′, C13′-C14′, and C14′-C15′ distances, respectively.
The rigid bond restraint was applied to the anisotropic thermal
Ack n ow led gm en t . This work was supported by
the Department of Energy (DE-FG02-00ER15036) and
Total Co. J .F.C. thanks the Centre National de la
Recherche Scientifique for a sabbatical leave.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal-
lographic data (positional and thermal parameters and bond
distances and angles) for C1-3 and C2-6; data are also available
for these compounds in CIF format. This material is available
free of charge via the Internet at http://pubs.acs.org.
OM0340443