Pyridine- and imidazole-phosphinimine bidentate ligand complexes: Considerations for ethylene oligomerization catalysts

Article abstract of DOI:10.1021/om030311t

The series of 2-substituted diphenylphosphine pyridines 1-5 were synthesized and subsequently oxidized with silyl or aryl azides to give the series of pyridine-phosphinimine ligands 2-(Me₃SiNPPh₂)C₅H₄N (9), 2-(2,6-Me₂C₆H₃NPPh₂) C₅H₄N (10), 2-(2,6-i-Pr₂C₆ H₃-NPPh₂)C₅ H₄N (11), 2-(2,6-Me₂C₆H₃ NPPh₂)-6-MeC₅H₄N (12), 2-(2,6-i-Pr₂C₆H₃NPPh₂)-6- MeC₅H₄N (13), 2-(2,6-Me₂C₆H₃NPPh₂)-6- BnC₅H₄N (14), 2-(2,6-i-Pr₂C₆H₃NPPh₂)-6- BnC₅H₄N (15), 2-(2,6-Me₂C₆H₃NPPh₂)-6- SiMe₃C₅H₄N (16), 2-(2,6-i-Pr₂C₆H₃NPPh₂)-6- SiMe₃C₅H₄N (17), 2-(2,6-Me₂C₆H₃NPPh₂)-6- PhC₅H₄N (18), and 2-(2,6-i-Pr₂C₆H₃NPPh₂)-6- PhC₅H₄N (19). Attempts to oxidize the fluorinated phosphine 2-P(C₆F₅)₂-6-PhC₅ H₃N (6) were unsuccessful. The ligand 9 reacted with PdCl₂(PhCN)₂ to the give the square-planar, diamagnetic compound (L)PdCl₂ (20; L = 9), while the remaining ligands were used to prepare (L)NiBr₂ and (L)-FeCl₂; complexes 21-30 and 31-40 (L = 10-19), respectively. In these complexes the P atoms become part of the chelate backbone. In addition, the pyridine-phosphinimines 2-(Ph₃P=NCH₂)(C₅H₄N) (44), 2-(Ph₃PNCH₂)-6-Me(C₅H₃N) (45), and 2-(Ph₃PNCH₂)-6-Ph(C₅H₃N) (46) were also prepared from the reaction of 2-azidomethyl-pyridines with PPh₃. In a similar fashion the complexes (L)PdCl₂ (47, 48; L = 44, 45), (L)NiBr₂ (49-51; L = 44-46), (L)FeCl₂ (52, 53), and (L)CoCl₂ (54, 55; L = 44, 45) were prepared. In addition, the imidazole-phosphines 1-Me-2-(PPh₂)C₃H₂N₂ (58), 1-Me-2-(PPh₂)-4,5-Ph₂C₃N₂ (59), and 1-Me-2-(PPh₂)-C₇H₆N₂ (60) were prepared and oxidized to give the imidazole-phosphinimines 1-Me-2-(2,6-Me₂C₆H₃N=PPh₂) C₃H₂N₂ (61), 1-Me-2-(2,6-i-Pr₂C₆H₃N=PPh₂) C₃H₂N₂ (62), 1-Me-2-(2,6-Me₂C₆H₃N=PPh₂)-4,5- Ph₂C₃N₂ (63), 1-Me-2-(2,6-i-Pr₂C₆H₃N=PPh₂)-4,5- Ph₂C₃N₂ (64), 1-Me-2-(2,6-Me₂C₆H₃N=PPh₂) C₇H₆N₂ (65), 1-Me-2-(2,6-i-Pr₂C₆H₃N=PPh₂) C₇H₆N₂ (66) and 1-Me-2-(2,6-i-Pr₂C₆H₃N=PPh₂)-4- (t-Bu)C₃HN₂ (67). Subsequent complexation afforded the species (L)PdCl₂ (68; L = 61), (L)NiBr₂ (69-75; L = 61-67), and (L)FeCl₂ (76-82; L = 61-67). Preliminary screening for activity as catalyst precursors for ethylene polymerization indicated that ethylene oligomerization may be occurring. In the case of complexes 30, 40, 74, and 82 activation with Et₂AlCl(ClC₆H₅) at 35°C under 300 psi of ethylene effected modest catalytic dimerization of ethylene to mainly C₄ alkenes. DFT computations suggested that inclusion of P into the ligand results in diminished electrophilicity at the metal and thus a weakened ethylene-metal interaction, accounting for the modest catalytic activity. X-ray structure determinations were obtained for 2, 20, 26, 27, 35, 37, 40, 49-51, 54, 68, 79, and 82.

Full text of DOI:10.1021/om030311t

Organometallics 2003, 22, 3841-3854
3841
P yr id in e- a n d Im id a zole-P h osp h in im in e Bid en ta te
Liga n d Com p lexes: Con sid er a tion s for Eth ylen e
Oligom er iza tion Ca ta lysts
Liam P. Spencer, Ramadan Altwer, Pingrong Wei, Lucio Gelmini,
J ames Gauld, and Douglas W. Stephan*
Department of Chemistry and Biochemistry, University of Windsor,
Windsor, Ontario, Canada N9B 3P4
Received April 28, 2003
The series of 2-substituted diphenylphosphine pyridines 1-5 were synthesized and
subsequently oxidized with silyl or aryl azides to give the series of pyridine-phosphinimine
ligands 2-(Me3SiNPPh2)C5H4N (9), 2-(2,6-Me2C6H3NPPh2)C5H4N (10), 2-(2,6-i-Pr2C6H3-
NPPh2)C5H4N (11), 2-(2,6-Me2C6H3NPPh2)-6-MeC5H4N (12), 2-(2,6-i-Pr2C6H3NPPh2)-6-
MeC5H4N (13), 2-(2,6-Me2C6H3NPPh2)-6-BnC5H4N (14), 2-(2,6-i-Pr2C6H3NPPh2)-6-BnC5H4N
(15), 2-(2,6-Me2C6H3NPPh2)-6-SiMe3C5H4N (16), 2-(2,6-i-Pr2C6H3NPPh2)-6-SiMe3C5H4N (17),
2-(2,6-Me2C6H3NPPh2)-6-PhC5H4N (18), and 2-(2,6-i-Pr2C6H3NPPh2)-6-PhC5H4N (19). At-
tempts to oxidize the fluorinated phosphine 2-P(C6F5)2-6-PhC5H3N (6) were unsuccessful.
The ligand 9 reacted with PdCl2(PhCN)2 to the give the square-planar, diamagnetic compound
(L)PdCl2 (20; L ) 9), while the remaining ligands were used to prepare (L)NiBr2 and (L)-
FeCl2 complexes 21-30 and 31-40 (L ) 10-19), respectively. In these complexes the P atoms
become part of the chelate backbone. In addition, the pyridine-phosphinimines 2-(Ph3Pd
NCH2)(C5H4N) (44), 2-(Ph3PNCH2)-6-Me(C5H3N) (45), and 2-(Ph3PNCH2)-6-Ph(C5H3N) (46)
were also prepared from the reaction of 2-azidomethyl-pyridines with PPh3. In a similar
fashion the complexes (L)PdCl2 (47, 48; L ) 44, 45), (L)NiBr2 (49-51; L ) 44-46), (L)FeCl2
(52, 53), and (L)CoCl2 (54, 55; L ) 44, 45) were prepared. In addition, the imidazole-
phosphines 1-Me-2-(PPh2)C3H2N2 (58), 1-Me-2-(PPh2)-4,5-Ph2C3N2 (59), and 1-Me-2-(PPh2)-
C7H6N2 (60) were prepared and oxidized to give the imidazole-phosphinimines 1-Me-2-(2,6-
Me2C6H3NdPPh2)C3H2N2 (61), 1-Me-2-(2,6-i-Pr2C6H3NdPPh2)C3H2N2 (62), 1-Me-2-(2,6-
Me2C6H3NdPPh2)-4,5-Ph2C3N2 (63), 1-Me-2-(2,6-i-Pr2C6H3NdPPh2)-4,5-Ph2C3N2 (64), 1-Me-
2-(2,6-Me2C6H3NdPPh2)C7H6N2 (65), 1-Me-2-(2,6-i-Pr2C6H3NdPPh2)C7H6N2 (66) and 1-Me-
2-(2,6-i-Pr2C6H3NdPPh2)-4-(t-Bu)C3HN2 (67). Subsequent complexation afforded the species
(L)PdCl2 (68; L ) 61), (L)NiBr2 (69-75; L ) 61-67), and (L)FeCl2 (76-82; L ) 61-67).
Preliminary screening for activity as catalyst precursors for ethylene polymerization indicated
that ethylene oligomerization may be occurring. In the case of complexes 30, 40, 74, and 82
activation with Et2AlCl(ClC6H5) at 35 °C under 300 psi of ethylene effected modest catalytic
dimerization of ethylene to mainly C4 alkenes. DFT computations suggested that inclusion
of P into the ligand results in diminished electrophilicity at the metal and thus a weakened
ethylene-metal interaction, accounting for the modest catalytic activity. X-ray structure
determinations were obtained for 2, 20, 26, 27, 35, 37, 40, 49-51, 54, 68, 79, and 82.
In tr od u ction
breakthrough in this area was the discovery that Ni-
and Pd-diimine complexes could effect olefin polymer-
ization catalysis with high activities at 25 °C and 1 atm
using methylaluminoxane (MAO) as the catalyst acti-
vator.3-7 Brookhart noted that the reduced steric bulk
of neutral R-diimine ligands resulted in polymers with
less branching and lower molecular weights.8 The
Late-transition metal complexes have demonstrated
potential as catalysts for the polymerization and oligo-
merization of olefins. The first industrial application of
such systems was the Shell Higher Olefin Process
(SHOP),1 in which a neutral Ni catalyst containing a
P-O chelating ligand effects the oligomerization of
ethylene to linear C4-C20 olefins. Subsequent work by
Keim et al. resulted in the development of a Ni-
iminophosphorane amidato ligand complex, which ef-
fected the polymerization of olefins.2 A significant
(2) Keim, W.; Appel, R.; Storeck, A.; Krueger, C.; Goddard, R. Angew.
Chem. 1981, 93, 91-92.
(3) Brookhart, M.; J ohnson, L. K.; Killian, C. M.; Mecking, S.;
Tempel, D. J . Polymer Prepr. (Am. Chem. Soc., Div. Polym. Chem.)
1996, 37, 254-255.
(4) Brookhart, M.; J ohnson, L. K.; Killian, C. M. Abstracts of Papers,
210th National Meeting of the American Chemical Society, Chicago,
IL, Aug 20-24, 1995; American Chemical Society: Washington, DC,
1995; PMSE-252.
* To whom correspondence should be addressed. Fax: 519-973-7098.
E-mail: stephan@uwindsor.ca.
(1) Keim, W.; Kowaldt, F. H.; Goddard, R.; Krueger, C. Angew.
Chem. 1978, 90, 493.
(5) Killian, C. M.; Tempel, D. J .; J ohnson, L. K.; Brookhart, M. J .
Am. Chem. Soc. 1996, 118, 11664-11665.
10.1021/om030311t CCC: $25.00 © 2003 American Chemical Society
Publication on Web 08/13/2003

3842 Organometallics, Vol. 22, No. 19, 2003
Spencer et al.
research groups of Brookhart9 and Gibson6 extended
such late-metal catalysis to Fe and Co species using a
bis(imino)pyridine ligand. More recently, Ni(II) com-
plexes of N-O salicylaldiminates were shown to be very
active single-component catalysts by Grubbs et al.,10
producing highly linear polyethylene. Brookhart et al.11
have also more recently developed a similar single-
component catalyst derived from the Ni complex of
2-(2,6-diisopropylanilino)tropone. In addition, Brookhart
and co-workers have shown that a cationic Ni(II)-allyl
complex of a P-O chelate affords highly active catalysts
in the absence of cocatalyst.12
the synthetic methods to two series of pyridine-phos-
phinimine ligands. In one case, the P atom is incorpo-
rated in the chelating ligand backbone, and in the other
the P atom is exocyclic of the chelate ring. In addition,
we describe the synthesis of imidazole-phosphinimine
ligands. In each case, these ligands have been suitably
substituted to provide a sterically protected pocket for
the transition metal. A number of late-metal complexes
have been prepared, and their utility in olefin polym-
erization/oligomerization has been evaluated. DFT cal-
culations provide insights into the modest activities and
future ligand design.
A number of late-metal phosphinimine complexes13-16
have been prepared; however, few have been examined
for their potential in catalysis. For example, Bochmann
et al. have reported the synthesis of group IX and X
complexes of bis(aryliminophosphoranyl)ethane, bis-
(aryliminophosphoranyl)methane, bis(aryliminophos-
phoranyl)methanide, and bis(aryliminophosphoranyl)-
pyridine ligands.17 The last of these complexes were
structurally reminiscent of the bis(imino)pyridine ligand
complexes developed by Brookhart and Gibson, although
upon activation, the bis(iminophosphoranyl)pyridine
complexes exhibited only modest activity. Very recently,
the complex 1,2-(C6H4(NPPh3)2)NiCl2 has been reported
to effect ethylene oligomerization,18 producing C4 and
C6 oligomers upon activation by Et2AlCl.
Exp er im en ta l Section
Gen er a l Da ta . All preparations were performed under a
dry, O2-free nitrogen atmosphere employing Schlenk line
techniques, an MBraun inert-atmosphere glovebox, or
a
Vacuum Atmospheres Co. glovebox unless otherwise stated.
Unless otherwise mentioned, all organic chemicals were
reagent grade and used as received from Aldrich Chemical Co.
All phosphines and metal compounds were purchased from
Strem Chemical Co. and were used as received. Et2O, EtOH,
C6H14, petroleum ether (bp 35-60 °C), CH2Cl2, and toluene
were either dried according to literature techniques or obtained
directly from an Innovative Technologies solvent purification
system. 1H, 13C{1H}, and 31P{1H} NMR spectra were recorded
on a Bruker Avance 300 spectrometer operating at 300, 75,
1
and 121 MHz, respectively. Several H, 13C{1H}, and 31P{1H}
We have previously developed several families of
highly active Ti-containing olefin polymerization cata-
lysts with phosphinimides as ancillary ligands.19,20 In
seeking to develop new late-metal olefin polymerization/
oligomerization catalysts, we have examined several
classes of chelating ligands incorporating phosphinimine
donors. These phosphinimide ligands are readily pre-
pared and derivatized, and in addition, they exhibit good
thermal stability while containing a convenient 31P
NMR spectroscopic handle. In this paper, we describe
NMR spectra were recorded on a Bruker Avance 500 MHz
spectrometer operating at 300, 121, and 202 MHz, respectively.
Trace amounts of protonated solvents were used as references
and chemical shifts reported relative to SiMe4. 31P{1H} spectra
were externally referenced to 85% H3PO4. All NMR spectra
were run in C6D6 at 25 °C, and the 13C{1H} resonances
reported are all singlets unless otherwise noted. Elemental
analyses were carried out by Guelph Chemical Labs Inc.,
Guelph, Ontario, Canada, or the Centre for Catalysis and
Materials Research (CCMR), Windsor, Ontario, Canada. In the
case of the ligands 44-46 and 61-66, elemental analysis data
were not obtained; however, 1H NMR data for these compounds
have been deposited as Supporting Information. GC analysis
was performed with a Shimadzu GC-9A apparatus with a
Quadrex Corp. fused silica glass capillary column (methyl
silicone, 25 m length, 0.25 mm i.d., and film thickness of 1.00
µm) working at 35 °C for 15 min and then heating at 25 °C
min-1 up to 275 °C. IR spectroscopy was performed on a
Bruker VECTOR 22 infrared Fourier transform spectrometer.
Unpaired electron measurements were made with a J ohnson
Matthey magnetic susceptibility balance (Evans design). 2-Br-
6-(SiMe3)C5H3N,21 2-Br-6-BnC5H3N,22 2-NH2-6-PhC5H3N and
2-Br-6-PhC5H3N,23 PCl(C6F5)2,24 2-(CHO)-6-Me(C5H3N),25 2-(N2-
CH2)-6-R(C5H3N)‚HCl (R ) Me, Ph),26 and 2-(CHO)-6-Ph-
(C5H3N)27 were prepared according to literature methods.
Me3SiN3, 2-Br-6-Me(C5H3N), 1-Me-C3H3N2, NiBr2(DME),
2-(PPh2)C3H3N (56),28 and 1-Me-2-(PPh2)-4-(t-Bu)C3HN2 (5)
were purchased from Aldrich Chemical Co.
(6) Britovsek, G. J . P.; Gibson, V.; Kimberley, B. S.; Maddox, P. J .;
McTavish, S. J .; Solan, G. A.; White, A. J . P.; Williams, D. J . Chem.
Commun. 1998, 849-850.
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35, 2475-2477.
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1995, 117, 6414-6415.
(9) Small, B. L.; Brookhart, M.; Bennett, A. M. A. J . Am. Chem.
Soc. 1998, 120, 4049-4050.
(10) Younkin, T. R.; Connor, E. F.; Henderson, J . I.; Friedrich, S.
K.; Grubbs, R. H.; Bansleben, D. A. Science (Washington, D.C.) 2000,
287, 460-462.
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3219.
(12) Liu, W.; Malinoski, J . M.; Brookhart, M. Organometallics 2002,
21, 2836-2838.
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Stam, C. H. Inorg. Chim. Acta 1991, 184, 73-87.
(14) Imhoff, P.; Van Asselt, R.; Elsevier: C. J .; Vrieze, K.; Goubitz,
K.; Van Malssen, K. F.; Stam, C. H. Phosphorus, Sulfur Silicon Relat.
Elem. 1990, 47, 401-415.
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182, 19-65.
(21) J utzi, P.; Lorey, O. J . Organomet. Chem. 1976, 104, 153-160.
(22) Minato, A.; Tamao, K.; Hayashi, T.; Suzuki, K.; Kumada, M.
Tetrahedron Lett. 1980, 21, 845-848.
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413.
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Casalnuovo, A. L.; Calabrese, J . C. J . Org. Chem. 1999, 64, 3429-
3447.
(16) Avis, M. W.; Goosen, M.; Elsevier, C. J .; Veldman, N.; Kooijman,
H.; Spek, A. L. Inorg. Chim. Acta 1997, 264, 43-60.
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L.; Maddox, P. J .; Bres, P.; Bochmann, M. J . Chem. Soc., Dalton Trans.
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Ethylene Oligomerization Catalysts
Organometallics, Vol. 22, No. 19, 2003 3843
Syn th esis of 2-P P h 2C5H4N (1), 2-P P h 2-6-MeC5H4N (2),
2-P P h 2-6-Bn C5H4N (3), 2-P P h 2-6-SiMe3C5H4N (4), a n d
2-P P h 2-6-P h C5H4N (5). Compounds 1-5 were prepared using
similar routes, using a modification of the literature procedure
for the preparation of 2-PPh2C5H4N; thus, only one preparation
is described.29,30 To a stirred THF solution (100 mL) of PHPh2
(2.66 g, 14.3 mmol) was added n-BuLi (5.7 mL; 2.5 M in
hexanes) and the deep red solution stirred overnight at 25 °C.
To this solution was added dropwise a 20 mL THF solution of
2-bromopyridine (2.26 g, 14.3 mmol). After the mixture was
stirred overnight, the solvent was removed in vacuo and EtOH
(30 mL) was added to quench the reaction. The solvent was
removed in vacuo, Et2O was added (30 mL), and the solution
was filtered. Removal of the ether in vacuo yielded a colorless
oily solid, which was recrystallized with CH2Cl2 and hexane.
Pr2C6H3NH2 (10.0 g, 56.4 mmol) and NaNO2 (4.3 g, 62.3 mmol)
were added to a cooled (-30 °C) acidic (40 mL of concentrated
HCl and 40 mL of distilled H2O) solution of NaBF4 (12.4 g,
112.9 mmol). After several minutes of stirring, a yellow
precipitate gradually formed, which was stirred at -30 °C for
30 min. The resulting intermediate diazonium BF4 salt was
filtered quickly in air and washed with cold H2O. This yellow
sticky powder was added to a cooled (0 °C) aqueous solution
(100 mL) of NaN3 (11.0 g, 169.2 mmol). After vigorous gas
evolution, the orange mixture was stirred overnight at 25 °C.
The product was extracted from the aqueous layer with diethyl
ether (3 × 30 mL) and dried with MgSO4. The solution was
filtered, and the solvent was removed to give a light red oil
(9.5 g, 83%). The oil was not purified, due to the risk of
explosion. 7: 1H NMR (CDCl3, δ) 1.28 (d, J H-H ) 9 Hz, 12H,
CHMe2), 3.38 (sept, J H-H ) 7 Hz 2H, CHMe2), 7.07-7.21 (m,
3H, C6H3). 8: 1H NMR (CDCl3, δ) 2.21 (s, 6H, Me), 6.67
(t, J H-H ) 8 Hz, 1H, p-C6H3), 6.96 (d, J H-H ) 8 Hz, 2H,
m-C6H3).
1
1: 80% yield based on Ph2PH. 31P{1H} NMR (δ): -3.2 (s). H
NMR (CDCl3, δ): 6.49 (m, 1H, py), 6.87 (m, 1H, py), 7.04-
7.09 (m, 7H, m-PPh2, p-PPh2, py), 7.50-7.53 (m, 4H, o-PPh2),
8.49 (d, 1H, py). 2: 70% yield, colorless crystals. 31P{1H} NMR
1
(d8-THF, δ): -4.0 (s). H NMR (d8-THF, δ): 2.48 (s, 3H, Me),
Syn t h esis of 2-(Me3SiNP P h 2)C5H 4N (9), 2-(2,6-Me2-
C6H3NP P h 2)C5H4N (10), 2-(2,6-i-P r 2C6H3NP P h 2)C5H4N (11),
2-(2,6-Me2C6H3NP P h 2)-6-MeC5H4N (12), 2-(2,6-i-P r 2C6H3N-
P P h 2)-6-MeC5H4N (13), 2-(2,6-Me2C6H3NP P h 2)-6-Bn C5H4N
(14), 2-(2,6-i-P r 2C6H3NP P h 2)-6-Bn C5H4N (15), 2-(2,6-Me2-
C6H3NP P h 2)-6-SiMe3C5H4N (16), 2-(2,6-i-P r 2C6H3NP P h 2)-
6-SiMe3C5H4N (17), 2-(2,6-Me2C6H3NP P h 2)-6-P h C5H4N (18),
a n d 2-(2,6-i-P r 2C6H3NP P h 2)-6-P h C5H4N (19). Compounds
9-19 were prepared by similar methods using the appropriate
phosphine and azide; thus, only one representative procedure
is described. To a toluene solution (50 mL) of 2-PPh2C5H4N
(1.0 g, 3.8 mmol) was added a THF solution of Me3SiN3 (0.88
g, 7.6 mmol). The solution was stirred at 25 °C for several
hours, and the solvent was removed to give a brown oil.
Petroleum ether was added to the mixture, which was stirred
for several hours and then stored at -30 °C overnight.
Filtration gave a cream-colored solid, which was washed
several times with hexane. 9: 99% yield, cream-colored solid,
6.82 (d, 1H, 9 Hz, py), 7.11 (m, 1H, py) 7.34 (m, 10 H, PPh2),
7.28 (m, 1H, py). 13C{1H} NMR (d8-THF, δ): 24.4, 120.4, 124.7
(d, J C-P ) 3 Hz), 128.3, 128.7 (d, J C-P ) 19 Hz), 132.4 (d, J C-P
) 3 Hz), 130.2 (d, J C-P ) 10 Hz), 136.0, 158.5 (d, J C-P ) 10
Hz), 162.9 (d, J C-P ) 4 Hz). 3: 65% yield, white solid. 31P{1H}
NMR (δ): -3.2 (s). 1H NMR (δ): 4.05 (s, 2H, CH2), 6.67 (d,
1H, py), 6.94 (t, 1H, 9 Hz, py), 6.99 (d, 1H, 9 Hz, py), 7.17-
7.23 (m, 11H, m-PPh2, p-PPh2, Ar), 7.59-7.63 (m, 4H, o-PPh2).
13C{1H} NMR (δ): 44.1, 117.6, 123.9, 125.9 (d, J C-P ) 4 Hz),
126.1, 127.4, 130.6, 131.3 (d, J C-P ) 19 Hz), 134.1, 135.5, 136.5
(d, J C-P ) 10 Hz), 139.5, 158.3 (d, J C-P ) 10 Hz), 161.1 (d,
J C-P ) 5 Hz). 4: 75% yield, golden oil. The oil was purified by
flash column chromatography on silica using hexanes. 31P{1H}
1
NMR (δ): -3.3 (s). H NMR (δ): 0.24 (s, 9H, SiMe3), 6.95 (m,
2H, py), 7.06-7.11 (m, 7H, m-PPh2, p-PPh2, py), 7.55 (m, 4H,
o-PPh2). 13C{1H} NMR (δ): -1.9, 126.7, 127.0, 128.3 (d, J C-P
) 3 Hz), 128.7, 133.2 (d, J C-P ) 19 Hz), 134.2 (d, J C-P ) 19
Hz), 137.1 (d, J C-P ) 11 Hz), 163.2 (d, J C-P ) 4 Hz), 168.9 (d,
J C-P ) 10 Hz). 5: 65% yield, cream-colored solid. 31P{1H} NMR
1
νPdN 1350 cm-1 31P{1H} NMR (δ): -4.9 (s). H NMR (CDCl3,
.
δ): 0.39 (s, 9H, -SiMe3), 6.50 (m, 1H, NAr), 7.00-7.15 (m,
8H, m-PPh2, p-PPh2, NAr, py), 7.94-7.99 (m, 4H, o-PPh2), 8.33
(m, 1H, py), 8.42 (m, 1H, py). 13C{1H} NMR (CDCl3, δ): 4.8
(d, J C-P ) 3 Hz), 124.5 (d, J C-P ) 3 Hz), 128.5, 131.3 (d, J C-P
) 2 Hz), 133.0 (d, J C-P ) 10 Hz), 135.9 (d, J C-P ) 9 Hz), 136.1
1
(CDCl3, 25 °C, δ): -3.0 (s). H NMR (CDCl3, δ): 7.07 (m, 1H,
py), 7.36-7.39 (m, 6H, m-PPh2, Ar), 7.39-7.41 (m, 2H, p-PPh2),
7.42 (m, 1H, py), 7.45-7.50 (m, 4H o-PPh2), 7.63 (m, 1H, py),
7.65 (m, 1H, Ar), 8.00 (m, 2H, Ar). 13C{1H} NMR (CDCl3, δ):
118.7, 126.4, 126.9, 128.4 (d, J C-P ) 4 Hz), 128.6, 128.9, 129.0,
134.3 (d, J C-P ) 19 Hz), 136.2 (d, J C-P ) 3 Hz), 136.6 (d, J C-P
) 11 Hz), 139.0, 157.1 (d, J C-P ) 12 Hz), 163.4 (d, J C-P ) 5
Hz).
(d, J C-P ) 100 Hz), 149.9 (d, J C-P ) 19 Hz), 159.0 (d, J C-P
)
.
135 Hz). 10: 95% yield, cream-colored solid, νPdN 1329 cm-1
31P{1H} NMR (δ): -17.0 (s). 1H NMR (δ): 2.42 (s, 6H, Me),
6.57-6.60 (m, 1H, py), 7.00 (t, J H-H ) 8 Hz, 1H, NAr), 7.09-
7.12 (m, 7H, m-PPh2, NAr, py), 7.28 (m, 2H, p-PPh2), 8.05-
8.10 (m, 4H, o-PPh2), 8.40 (m, 1H, py), 8.45 (m, 1H, py).
13C{1H} NMR (CDCl3, δ) 22.0, 119.1, 124.3 (d, J C-P ) 2.8 Hz),
127.9, 128.5, 128.7 (d, J C-P ) 19 Hz), 131.0 (d, J C-P ) 2 Hz),
132.2 (d, J C-P ) 8 Hz), 132.8 (d, J C-P ) 9 Hz), 134.8 (d, J C-P
) 99 Hz), 135.7 (d, J C-P ) 9 Hz), 147.9, 149.5 (d, J C-P ) 20
Hz), 158.6 (d, J C-P ) 137 Hz). 11: 95% yield, cream-colored
Syn th esis of 2-P (C6F 5)2-6-P h C5H3N (6). PhMgBr (1.0 M
in THF, 1.1 mL, 1.1 mmol) was added dropwise to a stirred
THF solution (10 mL) of PCl(C6F5)2 (0.25 g, 1.1 mmol) over a
period of 15 min to give a deep yellow solution. The solution
was stirred overnight, with no observable change in color. A
THF solution (5 mL) of PCl(C6F5)2 (402 mg, 1.1 mmol) was
then added dropwise, and the deep red solution was stirred
overnight. The solvent was removed in vacuo, and the residual
oil was extracted with pentane several times. The pentane
extracts were cooled to -35 °C and filtered to give the white
solid 8 (450 mg), which was washed several times with cold
pentane. Yield: 92%. 31P{1H} NMR (CDCl3, δ): -45.0 (quint,
solid, νPdN 1333 cm-1 31P{1H} NMR (δ): -6.9 (s). 1H NMR (δ):
.
1.14 (d, J H-H ) 9 Hz, 12H, CHMe2), 3.66 (sept, J H-H ) 8 Hz,
2H, CHMe2), 6.47-6.52 (m, 1H, py), 6.97-7.04 (m, 7H,
m-PPh2, NAr), 7.10 (m, 1H, py), 7.25-7.28 (m, 2H, p-PPh2),
7.89-7.99 (m, 4H, o-PPh2), 8.28-8.34 (m, 2H, py). 13C{1H}
NMR (CDCl3, δ): 24.4, 29.7, 120.4, 123.7, 124.7 (d, J C-P ) 3
Hz), 128.7, 129.2 (d, J C-P ) 19 Hz), 131.4 (d, J C-P ) 2 Hz),
133.2 (d, J C-P ) 9 Hz), 134.8 (d, J C-P ) 99 Hz), 136.0 (d, J C-P
) 7 Hz), 142.8 (d, J C-P ) 7 Hz), 144.9, 150.1 (d, J C-P ) 20
1
J P-F 30 Hz). H NMR (CDCl3, δ): 7.39-7.51 (m, 2H, Ar), 7.56
(m br, 2H, Ar), 7.65 (t, J H-H ) 8 Hz, 1H, py), 7.69 (d, J H-H
Hz, 1H, py), 8.00 (m, 2H, py).
8
Syn th esis of 2,6-i-P r 2C6H3N3 (7) a n d 2,6-Me2C6H3N3 (8).
These compounds were prepared by similar methods, using a
modification of a related literature method;31 thus, only one
representative procedure is described. A mixture of 2,6-i-
Hz), 158.5 (d, J C-P ) 139 Hz). 12: 85% yield, cream-colored
1
solid, νPdN 1342 cm-1
.
31P{1H} NMR (CDCl3, δ): -16.5 (s). H
NMR (CDCl3, δ): 2.40 (s, 6H, Me), 2.61 (s, 3H, Me), 6.62-
6.65 (m, 1H, NAr), 7.00 (m, 2H, NAr), 7.09-7.12 (m, 7H,
m-PPh2, p-PPh2, py), 7.28 (m, 2H, py), 8.05-8.10 (m, 4H,
o-PPh2). 13C{1H} NMR (CDCl3, δ) 22.0, 25.0, 119.0, 124.1 (d,
(29) Maisonnet, A.; Farr, J . P.; Olmstead, M. M.; Hunt, C. T.; Balch,
A. L. Inorg. Chem. 1982, 21, 3961-3967.
(30) Newkome, G. R.; Hager, D. C. J . Org. Chem. 1978, 43, 947-
J C-P ) 3 Hz), 127.9, 128.1 (d, J C-P ) 19 Hz), 131.3 (d, J C-P
)
949.
(31) Herring, D. L. J . Org. Chem. 1961, 26, 3998-3999.
3 Hz), 132.0, 132.2, 132.8 (d, J C-P ) 9 Hz), 134.3 (d, J C-P ) 99

3844 Organometallics, Vol. 22, No. 19, 2003
Spencer et al.
Hz), 135.0 (d, J C-P ) 9 Hz), 147.1, 149.2 (d, J C-P ) 21 Hz),
Syn t h esis of (2-(Me3SiNP P h 2)C5H4N)P d Cl2 (20). To a
toluene suspension (10 mL) of PdCl2(PhCN)2 (50 mg, 0.13
mmol) was added 9 (44 mg, 0.13 mmol) dissolved in 5 mL of
toluene. The orange solution was stirred overnight, and the
solvent volume was reduced to 3-5 mL. Et2O was added to
give a red precipitate, which was filtered. The solid was
washed with Et2O (3 × 5 mL), dried in vacuo, and recrystal-
lized by slow diffusion of a saturated CH2Cl2 layer into hexane
to give dark red crystals (76% yield). 31P{1H} NMR (CD2Cl2,
δ): 27.9 (s). 1H NMR (CD2Cl2, δ): 0.07 (s, 9H, SiMe3), 7.36
(m, 2H, py), 7.65 (m, 4H, m-PPh2), 7.77 (t, 2H, p-PPh2), 7.84-
7.88 (m, 4H, o-PPh2), 8.00 (m, 2H, py), 9.30 (d, 1H, 9 Hz, py).
13C{1H} NMR (CD2Cl2, δ): 4.5 (d, J C-P ) 3 Hz), 127.3, 128.5
(d, J C-P ) 121 Hz), 128.3, 129.5 (d, J C-P ) 13 Hz), 133.8 (d,
J C-P ) 11 Hz), 134.3 (d, J C-P ) 2 Hz), 138.6 (d, J C-P ) 10 Hz),
153.7 (d, J C-P ) 10 Hz), 159.0 (d, J C-P ) 130 Hz). Anal. Calcd
for C20H23Cl2N2PPdSi (527.79): C, 45.51; H, 4.39; N, 5.31.
Found: C, 45.02; H, 4.33; N, 5.34.
158.4 (d, J C-P ) 135 Hz). 13: 80% yield, cream-colored solid,
1
νPdN 1340 cm-1
.
31P{1H} NMR (CDCl3, δ): -13.6 (s). H NMR
(CDCl3, δ): 1.28 (d, J H-H ) 7 Hz, 12H, CHMe2), 2.55 (s, 3H,
Me), 3.40 (sept, J H-H ) 9 Hz, 2H, CHMe2), 6.79 (m, 1H, NAr),
6.95 (d, J H-H ) 7 Hz, 2H, NAr), 7.14 (m, 1H, py), 7.19 (m, 1H,
py), 7.39 (m, 4H, m-PPh2), 7.46 (m, 2H, p-PPh2), 7.63 (m, 1H,
py), 7.70 (m, 4H, o-PPh2). 13C{1H} NMR (CDCl3, δ): 24.0, 26.0,
30.2, 120.3, 123.5, 124.5 (d, J C-P ) 3 Hz), 128.5, 129.9 (d, J C-P
) 19 Hz), 131.5 (d, J C-P ) 3 Hz), 133.0, 133.6, 134.4 (d, J C-P
) 99 Hz), 135.0 (d, J C-P ) 7 Hz), 144.1, 150.5 (d, J C-P ) 20
Hz), 159.2 (d, J C-P ) 139 Hz). 14: 88% yield, cream-colored
solid, νPdN 1355 cm-1 31P{1H} NMR (d8-THF, δ): -17.2 (s). 1H
.
NMR (d8-THF, δ): 1.97 (s, 6H, Me), 4.08 (s, 2H, CH2), 6.46 (t,
J H-H ) 8 Hz, 1H, NAr), 6.77 (d, J H-H ) 8 Hz, 2H, NAr), 7.13-
7.20 (m, 5H, CH2Ph), 7.27-7.44 (m, 5H, o-PPh2, py), 7.73 (m,
1H, py), 7.76-7.80 (m, 4H, PPh2), 8.04 (t, 1H, 9.0 Hz, py). 13C-
{1H} NMR (d8-THF, δ) 21.1, 44.1, 117.6, 123.9, 125.9 (d, J C-P
) 19 Hz), 126.1, 127.4, 127.8 (d, J C-P ) 12 Hz), 128.1, 129.0,
130.6, 131.3 (d, J C-P ) 7 Hz), 132.3 (d, J C-P ) 9 Hz), 135.5 (d,
J C-P ) 99 Hz), 136.5 (d, J C-P ) 9 Hz), 139.5, 147.4, 157.4 (d,
J C-P ) 135 Hz), 161.1 (d, J C-P ) 20 Hz). 15: 85% yield, cream-
Syn th esis of (L)NiBr 2 (21-30; L ) 10-19). Compounds
21-30 were prepared by similar methods; thus, only one
representative procedure is described. To a slight excess of 11
(1.05 equiv, 200 mg, 0.29 mmol) and NiBr2(DME) (86 mg, 0.278
mmol) was added 10 mL of CH2Cl2. The blue suspension was
stirred overnight and then was concentrated to several mil-
liliters in vacuo. Et2O (10 mL) was added, and the mixture
was filtered to give a light blue powder. 21‚CH2Cl2: 90% yield,
blue powder, νPdN 1213 cm-1, µeff ) 2.90 µB. Anal. Calcd for
colored solid, νPdN 1330 cm-1 31P{1H} NMR (d8-THF, δ): -16.5
.
(s). 1H NMR (d8-THF, δ): 0.86 (d, J H-H ) 7 Hz, 12H, CHMe2),
3.32 (sept, J H-H ) 7 Hz, 2H, CHMe2), 4.08 (s, 2H, CH2), 6.64
(m, 1H, NAr), 6.84 (m, 2H, NAr), 7.12-7.18 (m, 5H, CH2Ph),
7.28-7.46 (m, 8H, m-PPh2, p-PPh2, py), 7.69-7.78 (m, 5H,
o-PPh2, py), 7.97 (m, 1H, py). 13C{1H} NMR (CDCl3, δ): 23.1,
29.6, 45.2, 119.7, 123.2, 125.0, 127.0 (d, J C-P ) 10 Hz), 127.2
(d, J C-P ) 10 Hz), 128.9 (d, J C-P ) 12 Hz), 129.3, 130.1, 131.7,
133.5 (d, J C-P ) 9 Hz), 135.5 (d, J C-P ) 100 Hz), 137.5 (d, J C-P
C
26H25Br2Cl2NiN2P (685.87): C, 45.53; H, 3.67; N, 4.08.
Found: C, 45.26; H, 3.59; N, 4.16. 22: 95% yield, blue powder,
νPdN 1244 cm-1, µeff ) 2.95 µB. Anal. Calcd for C29H31Br2NiN2P
(657.05): C, 53.01; H, 4.76; N, 4.26. Found: C, 53.21; H; 4.75;
) 9 Hz), 140.6, 142.8 (d, J C-P ) 7 Hz), 145.3, 157.5 (d, J C-P
136 Hz), 162.4 (d, J C-P ) 19 Hz). 16: 90% yield, cream-colored
solid, νPdN 1339 cm-1 31P{1H} NMR (δ): -16.6 (s). 1H NMR
)
N, 4.21. 23: 85% yield, light green powder, νPdN 1193 cm-1
,
µeff ) 3.10 µB. Anal. Calcd for C26H25Br2NiN2P (614.97): C,
50.78; H, 4.10; N, 4.56. Found: C, 50.58; H, 4.14; N 4.96. 24:
80% yield, light blue powder, νPdN 1242 cm-1, µeff ) 3.20 µB.
Anal. Calcd for C30H33Br2NiN2P (671.07): C, 53.69; H, 4.96;
N, 4.17. Found: C, 53.57; H, 4.85; N, 4.39. 25: 84% yield, blue
.
(δ): 0.23 (s, 9H, -SiMe3), 2.46 (s, 6H, Me), 7.03-7.14 (m, 9H,
m-PPh2, p-PPh2, NAr), 7.33 (m, 1H, py), 8.04-8.13 (m, 5H,
o-PPh2, py), 8.40 (m, 1H, py). 13C{1H} NMR (CDCl3, δ): -2.0,
20.6, 118.5, 127.3 (d, J C-P ) 20 Hz), 127.8, 127.9 (d, J C-P ) 12
Hz), 129.0 (d, J C-P ) 3 Hz), 131.0 (d, J C-P ) 2 Hz), 132.0 (d,
J C-P ) 17 Hz), 132.6 (d, J C-P ) 9 Hz), 133.9 (d, J C-P ) 9 Hz),
134.0 (d, J C-P ) 100 Hz), 147.4, 157.5 (d, J C-P ) 132 Hz), 168.7
(d, J C-P ) 17 Hz). 17: 92% yield, cream-colored solid, νPdN 1332
powder, νPdN 1216 cm-1, µeff ) 3.15 µB. Anal. Calcd for C32H29
-
Br2NiN2P (691.06): C, 55.62; H, 4.23; N, 4.05. Found: C, 55.58;
H, 4.52; N, 3.62. 26: 78% yield, dark blue crystals, νPdN 1258
cm-1, µeff ) 2.97 µB. Anal. Calcd for C36H37Br2NiN2P (747.17):
C, 57.87; H, 4.99; N, 3.75. Found: C, 57.91; H, 5.27; N, 3.46.
27‚CH2Cl2: 75% yield, royal blue crystals, νPdN 1217 cm-1
,
cm-1 31P{1H} NMR (CDCl3, δ): -12.6 (s). 1H NMR (CDCl3, δ):
.
µeff ) 3.07 µB. Anal. Calcd for C28H31Br2NiN2PSi (673.12): C,
49.96; H, 4.64; N, 4.16. Found: C, 49.66; H, 4.92; N, 3.90. 28‚
0.5CH2Cl2: 74% yield, blue-green powder, νPdN 1255 cm-1, µeff
) 3.23 µB. Anal. Calcd for C32H39Br2NiN2PSi (779.71): C, 50.83;
H, 5.43; N, 3.59. Found: C, 50.53; H, 5.09; N, 3.45. 29‚H2O:
90% yield, purple powder, νPdN 1217 cm-1, µeff ) 2.95 µB. Anal.
Calcd for C31H27Br2NiN2P (677.03): C, 53.57; H, 4.21; N, 4.03.
Found: C, 54.00; H, 4.50; N, 3.70. 30: 92% yield, blue-green
0.19 (s, 9H, -SiMe3), 0.91 (d, J H-H ) 9 Hz, 12H, CHMe2), 3.35
(sept, J H-H ) 9 Hz, 2H, CHMe2), 6.85 (m, 1H, NAr), 6.97 (m,
2H, NAr), 7.27-7.54 (m, 7H, m-PPh2, p-PPh2, py), 7.69 (m,
1H, py), 7.72-7.79 (m, 4H, o-PPh2), 7.95 (m, 1H, py). 13C{1H}
NMR (CDCl3, δ): -2.0, 23.6, 28.6, 118.9, 122.6, 127.3 (d, J C-P
) 20 Hz), 127.8 (d, J C-P ) 12 Hz), 128.8 (d, J C-P ) 3 Hz), 130.8
(d, J C-P ) 2 Hz), 132.6 (d, J C-P ) 9 Hz), 133.7 (d, J C-P ) 9
Hz), 133.9 (d,1J C-P ) 101 Hz), 142.5 (d, J C-P ) 7 Hz), 144.2,
157.0 (d, J C-P ) 132 Hz), 168.7 (d, J C-P ) 17 Hz). 18: 92%
powder, νPdN 1241 cm-1, µeff ) 2.91 µB. Anal. Calcd for C35H35
-
yield, white solid, νPdN 1342 cm-1
.
31P{1H} NMR (CDCl3, δ):
Br2NiN2P (733.14): C, 57.34; H, 4.81; N, 3.82. Found: C, 57.35;
H, 5.16; N, 3.58.
1
-11.9 (s). H NMR (CDCl3, δ): 2.07 (s, 6H, Me), 6.66 (m, 1H,
NAr), 6.93 (m, 2H, NAr), 7.38-7.44 (m, 7H, m-PPh2, Ar, py),
7.50 (m, 2H, p-PPh2), 7.80-7.88 (m, 8H, o-PPh2, Ar, py), 8.05
(m, 1H, py). 13C{1H} NMR (CDCl3, δ): 21.4, 118.5, 121.0, 126.6,
126.8, 127.7, 128.0 (d, J C-P ) 12 Hz), 128.7, 129.3, 131.0, 131.1,
132.6 (d, J C-P ) 9 Hz), 133.5 (d, J C-P ) 100 Hz), 136.7 (d, J C-P
) 8 Hz), 138.4, 147.2, 156.6 (d, J C-P ) 19 Hz), 157.0 (d, J C-P
Syn th esis of (L)F eCl2 (31-40; L ) 10-19). Compounds
31 to 40 were prepared by similar methods; thus, only one
representative procedure is described. To a slight excess of 19
(1.05 equiv, 200 mg, 0.39 mmol) and FeCl2 (47 mg, 0.37 mmol)
was added 10 mL of THF. The orange suspension was stirred
overnight and then was concentrated to 3-5 mL in vacuo. Et2O
(10 mL) was added, and the mixture was then filtered to give
an orange powder. 31: 92% yield, orange powder, νPdN 1211
cm-1, µeff ) 4.95 µB. Anal. Calcd for C25H23Cl2FeN2P (509.19):
C, 58.97; H, 4.55; N, 5.50. Found: C, 58.99; H, 4.73; N, 5.17.
32: 87% yield, light orange solid, νPdN 1237 cm-1, µeff ) 5.04
µB. Anal. Calcd for C29H31Cl2FeN2P (565.29): C, 61.62; H, 5.53;
N, 4.96. Found: C, 61.91; H, 5.42; N, 4.86. 33: 95% yield, dull
orange solid, νPdN 1188 cm-1, µeff ) 5.12 µB. Anal. Calcd for
) 132 Hz). 19: 95% yield, white solid, νPdN 1357 cm-1
.
31P-
{1H} NMR (CDCl3, δ): -11.9 (s). H NMR (CDCl3, δ): 0.90 (d,
J H-H ) 7 Hz, 2H, CHMe2), 3.97 (sept, J H-H ) 7 Hz, 2H,
CHMe2), 6.84 (dt, 8 Hz, 2 Hz, 1H, NAr), 6.99 (dd, 8 Hz, 1 Hz,
2H, NAr), 7.37-7.43 (m, 7H, m-PPh2, Ar, py), 7.49 (m, 2H,
p-PPh2), 7.75-7.80 (m, 4H, o-PPh2), 7.81-7.85 (m, 4H, Ar, py),
7.91 (m, 1H, py).13C{1H} NMR (CDCl3, δ): 22.8, 28.6, 119.1,
120.9, 122.7, 125.9, 126.6, 128.0 (d, J C-P ) 11 Hz), 128.7, 129.4,
131.1, 132.6 (d, J C-P ) 7 Hz), 133.9 (d, J C-P ) 100 Hz), 136.8
(d, J C-P ) 8 Hz), 138.4, 142.7, 144.1, 156.0 (d, J C-P ) 130 Hz),
156.7 (d, J C-P ) 19 Hz).
1
C
26H25Cl2FeN2P (523.21): C, 59.68; H, 4.82; N, 5.35. Found:
C, 59.50; H, 4.75; N, 5.55. 34: 85% yield, orange solid, νPdN
1242 cm-1, µeff ) 5.24 µB. Anal. Calcd for C30H33Cl2FeN2P

Ethylene Oligomerization Catalysts
Organometallics, Vol. 22, No. 19, 2003 3845
1
(579.32): C, 62.20; H, 5.74; N, 4.84. Found: C, 62.32; H, 5.93;
N, 4.50. 35‚CH2Cl2: 67% yield, deep orange crystals, νPdN 1215
cm-1, µeff ) 5.14 µB. Anal. Calcd for C33H31Cl4FeN2P (684.24):
C, 57.93; H, 4.57; N, 4.09. Found: C, 57.47; H, 5.14; N, 3.86.
31P NMR (CD2Cl2, δ): 36.5 (s). H NMR (CD2Cl2, δ): 8.45 (d,
1H, py), 7.25 (d, J H-H ) 1 Hz, 1H, py), 7.09-7.06 (m, 1H, py),
6.98 (t, J H-H ) 3 Hz, 1 H, py), 4.08 (s, 2H, CH2). 13C{H} NMR
(CD2Cl2, δ): 156.8, 149.40, 135.9, 123.7, 128.0 (d, J C-P ) 150
Hz) 121.9, 122.0, 25.0. Anal. Calcd for C24H22N2PPdCl2: C,
52.80; H, 3.85; N, 5.13. Found: C, 51.82; H, 4.04; N, 5.42. 48:
36‚CH2Cl2: 76% yield, orange crystals, νPdN 1258 cm-1, µeff
)
5.20 µB. Anal. Calcd for C37H39Cl4FeN2P (740.35): C, 60.03;
H, 5.31; N, 3.78. Found: C, 59.82; H, 5.61; N, 3.39. 37: 76%
yield, orange-red crystals, νPdN 1213 cm-1, µeff ) 5.07 µB. Anal.
Calcd for C28H31Cl2FeN2PSi (581.37): C, 57.85; H, 5.37; N,
4.82. Found: C, 57.86; H, 5.45; N, 4.84. 38: 72% yield, orange
78% yield, yellow powder, νPdN 1279 cm-1
,
31P NMR (CD2Cl2,
1
δ): 37.0 (s). H NMR (CD2Cl2, δ): 8.65 (d, J H-H ) 3 Hz, 2H,
Ar), 8.57 (d, J H-H ) 45 Hz, 2H, Ar), 7.85-7.80 (m, 11H, Ar),
7.47 (d, J H-H ) 2 Hz, 1H, py), 7.25-7.09 (m, 1H, py), 7.08 (t,
J H-H ) 6 Hz, 1H, py), 5.10 (s, 2H, CH2), 2.54 (s, 3H, Me). 13C-
{1H} NMR (CD2Cl2, δ): 158.2, 136.1, 128.0 (d, J C-P ) 120 Hz),
120.0, 122.0, 26.0, 16.0. Anal. Calcd for C25H22N2PPdCl2: C,
51.40; H, 4.31; N, 8.00. Found: C, 50.78; H, 4.17; N, 8.42. 49:
55% yield, purple powder, νPdN 1280 cm-1, µeff ) 2.35 µB. 31P-
{1H} NMR (CD2Cl2): δ 41.3 (s). Anal. Calcd for C24H22N2-
PNiBr2: C, 50.13; H, 3.40; N, 4.77. Found: C, 50.40; H, 3.98;
crystals, νPdN 1254 cm-1, µeff ) 4.99 µB. Anal. Calcd for C32H39
-
Cl2FeN2PSi (637.48): C, 60.29; H, 6.17; N, 4.39. Found: C,
60.07; H, 6.15; N, 4.12. 39‚H2O: 55% yield, dark orange
crystals, νPdN 1242 cm-1, µeff ) 5.35 µB. Anal. Calcd for C31H29
-
Cl2FeN2OP (603.30): C, 61.72; H, 4.85; N, 4.64. Found: C,
61.60; H, 5.08; N, 4.19. 40‚H2O: 65% yield, dark orange
crystals, νPdN 1217 cm-1, µeff ) 5.19 µB. Anal. Calcd for C35H37
-
Cl2FeN2OP (659.41): C, 63.75; H, 5.66; N, 4.25. Found: C,
63.69; H, 5.68; N, 4.13.
N, 5.14. 50: 60% yield, purple powder. νPdN 1278 cm-1, µeff
2.98 µB. 31P{1H} NMR (CD2Cl2, δ): 40.1 (s). Anal. Calcd for
24H22N2PNiBr2: C, 50.35; H,3.57; N, 4.78. Found: C, 50.12;
H, 4.10; N, 5.01. 51: 70% yield, purple powder, νPdN 1270 cm-1
µeff ) 3.02 µB. 31P{1H} NMR (δ): 40.3 (s). Anal. Calcd for
25H23N2PNiBr2: C, 54.33; H, 3.77; N, 4.22. Found: C, 54.04;
H, 4.17; N, 5.01. 52: 60% yield. green powder, νPdN 1231 cm-1
)
C
Syn th esis of 2-(N3CH2)(C5H4N) (41), 2-(N3CH2)-6-Me-
(C5H3N) (42), 2-(N3CH2)-6-P h (C5H3N) (43). To a stirred
solution of 2-(ClCH2)(C5H4N)‚HCl (18.28 mmol, 3.00 g) in 100
mL of H2O was added 21.9 mmol (1.426 g) of NaN3. The stirred
mixture was refluxed for 2 days and then cooled, and the
solution was neutralized with NaHCO3. The product was
extracted into CH2Cl2, and the organic layer was dried over
anhydrous MgSO4. After filtration the solvent was removed
under vacuum to give the brown oil 41 (70%). The oil was not
purified due to the risk of explosion. 1H NMR (δ): 8.45 (d, J H-H
) 3 Hz, 1H, py), 7.25 (d, J H-H ) 1 Hz, 1H, py), 7.09-7.06 (m,
1H, py), 6.98 (t, J H-H ) 3 Hz, 1H, py), 4.08 (s, 2H, CH2). 13C-
,
C
,
µeff ) 4.98 µB. Anal. Calcd for C25H23N2PFeCl2: C, 56.49; H,
4.47; N, 6.62. Found: C, 56.61; H, 4.99; N, 6.71. 53: 65% yield,
green powder, νPdN 1225 cm-1, µeff ) 5.11 µB. Anal. Calcd for
C
25H22N2PFeCl2: C, 56.49; H, 4.47; N, 6.62. Found: C, 56.11;
H, 4.17; N, 6.70. 54: 70% yield, blue powder, νPdN 1260 cm-1
,
µeff ) 4.08 µB. Anal. Calcd for C24H22N2PCoCl2: C. 57.85; H.
4.21; N. 5.62. Found: C. 57.64; H. 4.24; N. 5.70. 55: 75% yield,
blue powder, νPdN 1252 cm-1, µeff ) 5.23 µB. Anal. Calcd for
{1H} NMR (CD2Cl2, δ): 156.8, 150.2, 136.6, 128.7 (d, J C-P
)
1
C
25H22N2PCoCl2: C, 58.39; H, 4.71; N, 5.71. Found: C, 58.61;
99 Hz), 122.9, 122.0, 55.0. 42: 85% yield, brown oil. H NMR
(CDCl3, δ): 7.58 (d, J H-H ) 12 Hz, 1H, py), 7.13 (t, J H-H ) 3
Hz, 1H, py), 7.09 (d, J H-H ) 3 Hz, 1H, py), 4.43 (s, 2H, CH2),
2.55 (s, 3H, Me). 13C{1H} NMR (CD2Cl2, δ): 158.2, 149.2, 136.1,
120.0 (d, J C-P ) 8 Hz), 122.9, 122.0, 56.0, 21.2. 43: 80% yield,
H, 4.82; N, 6.19.
Syn th esis of 1-Me-2-(P P h 2)C3H2N2 (58), 1-Me-2-(P P h 2)4,5-
P h 2C3N2 (59), 1-Me-2-(P P h 2)C7H6N2 (60). Compounds 58-
60 were prepared by similar methods; thus, only one repre-
sentative procedure is described. To a cooled (-78 °C) THF
(50 mL) solution of 1-Me-C3H3N2 (5.0 g, 60.9 mmol) was added
n-BuLi (28 mL, 2.5 M in hexanes, 70 mmol) dropwise. The
solution was stirred for 1 h, and Ph2PCl (12.0 mL, 67.1 mmol)
was added in a dropwise fashion. The solution was gradually
warmed to 25 °C and stirred overnight. The solvent was
removed in vacuo, and Et2O (75 mL) and H2O (50 mL) were
added. The organic layer was collected, and the aqueous layer
was washed with ether (30 mL). The ether layer was dried
over MgSO4 and filtered, and the solvent was removed to give
a white solid. The product was recrystallized with CH2Cl2/
hexane to give a microcrystalline solid (90% yield). 58: 31P-
{1H} NMR (δ): -30.0 (s). 1H NMR (δ): 3.75 (s, 3H, -NMe),
7.05 (m, 1H, imid), 7.27 (d, 1 Hz, 1H, imid), 7.27-7.37 (m, 6H,
m-PPh2, p-PPh2), 7.43-7.49 (m, 4H, o-PPh2). 13C{1H} NMR
(δ): 34.2 (d, J C-P ) 14 Hz), 123.8, 128.8 (d, J C-P ) 8 Hz), 129.3,
131.1, 134.1 (d, J C-P ) 20 Hz), 135.0 (d, J C-P ) 4 Hz), 146.0.
59: 85% yield, white microcrystalline solid. 31P{1H} NMR (δ):
1
light brown oil. H NMR (CDCl3, δ): δ 8.02 (d, J H-H ) 3 Hz,
3H, Ar), 7.54-7. 37 (m, 2H, Ar), 7.5-7.3 (m, 1H, py), 7.08 (t,
J H-H ) 6 Hz, 1H, py), 6.87 (d, J H-H ) 1 Hz, 1H, py), 4.52 (s,
2H, CH2). 13C{1H} NMR (CD2Cl2, δ): 156.8, 157.0, 139.7, 137.1,
129, 127 (t, J C-P ) 44 Hz), 119.4 (d, J C-P ) 2 Hz), 56.0.
Syn th esis of 2-(P h 3P NCH2)C5H4N (44), 2-(P h 3P NCH2)-
6-MeC5H3N (45), 2-(P h 3P NCH 2)-6-P h C5H3N (46). To a
stirred solution of 41 (7.40 mmol, 1.00 g) in toluene (50 mL)
under N2 was added PPh3 (3.70 mmol, 0.97 g). The mixture
was heated for 6 h and cooled and then the solvent removed
under vacuum to give a yellow powder of 44: 86% yield, white
1
solid, νPdN 1360 cm-1
.
31P NMR (δ): 7.8 (s). H NMR (δ): 8.48
(d, J H-H ) 9 Hz, 1H, py), 7.86-7.80 (m, 11H, Ar), 7.78 (d, J H-H
) 6 Hz, 4H, Ar), 7.25 (d, J H-H ) 1 Hz, 1H, py), 7.16 (t, J H-H
)
3 Hz, 1H, py), 7.14-7.01 (m, 1H, py), 5.09 (s, 2H, CH2). 13C-
{1H} NMR (CD2Cl2, δ): 156.8, 149.4, 135.9, 123.7, 128.0 (d,
J C-P ) 150 Hz) ,121.9, 122.0, 42.0. 45: 80% yield, white solid,
1
νPdN 1358 cm-1
.
31P{1H} NMR (δ): 7.8 (s). H NMR (δ): 8.66
1
-29.5 (s). H NMR (δ): 3.55 (s, 3H, Me), 7.13 (m, 1H, imid),
(d, 2H, Ar), 8.57 (d, J H-H ) 42 Hz, 2H, Ar), 7.85-7.80 (m, 11H,
Ar), 7.50-7.44 (d, J H-H ) 18 Hz, 1H, py), 7.25-7.09 (m, 1H,
py), 7.08 (t, J H-H ) 6 Hz, 1H, py), 5.10 (s, 2H, CH2), 2.54 (s,
3H, Me). 13C{1H} NMR (CD2Cl2): δ 158.2, 136.1, 128.1 (d, J C-P
7.19 (m, 2H, Ar H), 7.35-7.40 (m, 8H, m-PPh2, p-PPh2, Ar H),
7.45-7.47 (m, 3H, Ar H, imid), 7.51 (m, 2H, Ar H), 7.67-7.70
(m, 4H, o-PPh2). 13C{1H} NMR (δ): 32.5 (d, J C-P ) 15 Hz),
126.2, 126.7, 128.0, 128.4 (d, J C-P ) 8 Hz), 128.6, 128.9, 129.0,
130.8, 131.3, 132.1, 134.0 (d, J C-P ) 20 Hz), 134.9, 135.5 (d,
J C-P ) 5 Hz), 139.8, 145.0. 60: 86% yield, white powder. 31P-
) 90 Hz), 48.8, 21.2. 46: 55% yield, yellow solid, νPdN 1355
1
cm-1
.
31P NMR (δ): 7.9 (s). H NMR (δ): 7.76-7.72 (m, 11H,
Ph), 7.54 (t, J H-H ) 3 Hz, 4H, Ph). 7.99 (d, J H-H ) 1 Hz, 2H,
Ar), 7.35 (d, J H-H ) 2 Hz, 2H, Ar), 7.28 (s, 1H, Ar), 7.38 (s,
1H, py), 7.46 (d, J H-H ) 1 Hz, 1H, py), 7.44 (d, J H-H ) 1 Hz,-
1H, py), 5.34 (s, 2H, CH2). 13C{1H} NMR (CD2Cl2, δ): 158.8,
157.0, 137.1, 129.0, 128.0 (d, J C-P ) 159 Hz), 127.1, 119.4, 48.8.
Syn th esis of (L)P d Cl2 (47, 48; L ) 44, 45), (L)NiBr 2 (49-
51; L ) 44-46), (L)F eCl2 (52, 53; L ) 44, 45), a n d (L)CoCl2
(54, 55; L ) 44, 45). These metal complexes of the bidentate
ligands were prepared using methods similar to those de-
{1H} NMR (δ): -24.9 (s). H NMR (δ): 3.83 (s, 3H, Me), 7.27
1
(m, 2H, benzimid), 7.32 (m, 1H, benzimid), 7.36-7.38 (m, 7H,
m-PPh2, p-PPh2, benzimid), 7.51-7.54 (m, 4H, o-PPh2), 7.83
(d, 1H, benzimid). 13C{1H} NMR (δ): 31.3 (d, J C-P ) 14 Hz),
109.4, 120.7, 122.2, 123.2, 129.0 (d, J C-P ) 7.8 Hz), 129.7, 133.9
(d, J C-P ) 5 Hz), 134.3 (d, J C-P ) 20 Hz), 137.2, 144.4 (d, J C-P
) 7 Hz), 154.3 (d, J C-P ) 3 Hz).
Syn t h esis of 1-Me-2-(2,6-Me2C6H3NP P h 2)C3H2N2 (61),
2
scribed above. 47: 80% yield, yellow powder, νPdN 1286 cm-1
.
1-Me-2-(2,6-i-P r 2C6H3NP P h 2)C3H2N2 (62), 1-Me-2-(2,6-Me2-

3846 Organometallics, Vol. 22, No. 19, 2003
Spencer et al.
C6H3NP P h 2)-4,5-P h 2C3N2 (63), 1-Me-2-(2,6-i-P r 2C6H3NP P h 2)-
4,5-P h 2C3N2 (64), 1-Me-2-(2,6-Me2C6H3NP P h 2)C7H6N2 (65),
1-Me-2-(2,6-i-P r 2C6H 3NP P h 2)C7H 6N2 (66), 1-Me-2-(2,6-i-
P r 2C6H3NP P h 2)-4-t-Bu C3HN2 (67). Compounds 61-67 were
prepared by similar methods; thus, only one representative
procedure is described. To a THF solution (50 mL) of 58 (1.50
g, 5.6 mmol) was added 2,6-Me2C6H3N3 (1.7 g, 10.2 mmol). The
solution was heated at 60 °C overnight, and the solvent was
subsequently removed to give a brown oil. Petroleum ether
was added and the mixture was stirred at -30°C overnight.
Filtration gave 2.0 g (93%) of a cream-colored solid, νPdN 1352
cm-1. 61: 31P{1H} NMR (δ): -16.0 (s).1H NMR (δ): 1.96 (s,
6H, Me), 3.68 (s, 3H, NMe), 6.67 (dt, J H-H ) 8, 2 Hz, 1H, NAr
H), 6.90 (d, 7 Hz, 2H, NAr H), 7.05 (m, 1H, imid), 7.23 (m, 1H,
imid), 7.41-7.47 (m, 4H, m-PPh2), 7.53 (dt, J H-H ) 6, 2 Hz,
2H, p-PPh2), 7.69-7.77 (m, 4H, o-PPh2). 13C{1H} NMR (δ):
18.2, 34.9, 119.6, 125.3, 127.5 (d, J C-P ) 12 Hz), 127.9, 128.7
(d, J C-P ) 13 Hz), 130.0 (d, J C-P ) 15 Hz), 131.9, 132.2 (d,
J C-P ) 10 Hz), 132.7, 143.0 (J C-P ) 128 Hz), 145.8. 62: 95%
(δ): 22.6, 28.7, 30.2, 31.9, 34.1, 118.7, 119.1, 122.6, 128.1 (d,
J C-P ) 13 Hz), 131.1, 132.3 (d, J C-P ) 10 Hz), 132.5 (d, J C-P
)
113 Hz) 141.5 (d, J C-P ) 131 Hz), 142.6 (d, J C-P ) 8 Hz), 143.6,
152.9 (d, J C-P ) 14 Hz).
Syn t h esis of (1-Me-2-(2,6-i-P r 2C6H 3NP P h 2)C3H 2N2)-
P d Cl2‚MeCN (68). To a stirred solution of (PhCN)2PdCl2 (44
mg, 0.11 mmol) in toluene was added a toluene solution (5 mL)
of 62 (50 mg, 0.11 mmol). The red solution was stirred for 2 h,
and an orange precipitate gradually formed. After 2 h, the
solution was cooled to -30 °C and filtered, and the solid was
washed with cold toluene several times. The orange solid was
recrystallized by dissolving in MeCN and cooling to -30 °C to
give orange crystals. 31P{1H} NMR (d6-DMSO, δ): 28.2 (s). 1H
NMR (d6-DMSO, δ): 0.27 (d, J H-H ) 7 Hz, 6H, CHMe2), 1.32
(d, J H-H ) 7 Hz, 6H, CHMe2), 3.30 (s, 3H, NMe), 3.32 (sept, 7
Hz, 2H, CHMe2), 6.76 (d, J H-H ) 8 Hz, 2H, NAr H), 6.96 (dt,
J H-H ) 8 Hz, 2 Hz, 1H, NAr H), 7.65-7.72 (m, 8H, m-PPh2,
p-PPh2, imid), 7.77-7.82 (m, 4H, o-PPh2). 13C{1H} NMR (d6-
DMSO, δ): 22.5, 25.1, 28.3, 35.8, 122.0, 123.1, 123.3, 125.3,
128.6, 129.9 (d, J C-P ) 15 Hz), 132.5 (d, J C-P ) 10 Hz), 134.5,
137.2, 140.0 (d, J C-P ) 165 Hz), 147.2 (d, J C-P ) 5 Hz). Anal.
Calcd for C30H35Cl2N4PPd (659.93): C, 54.60; H, 5.35; N, 8.49.
Found: C, 54.13; H, 5.29; N, 8.39.
yield, cream-colored solid, νPdN 1358 cm-1 31P{1H} NMR (δ):
.
-16.3 (s).1H NMR (δ): 0.88 (d, 7 Hz, 12H, CHMe2), 3.22 (sept,
7 Hz, 2H, -CHMe2), 3.67 (s, 3H, Me), 6.85 (m, 1H, NAr H),
6.96 (m, 2H, NAr H), 7.04 (s, 1H, imid), 7.21 (s, 1H, imid),
7.42-7.46 (m, 4H, m-PPh2), 7.52 (m, 2H, p-PPh2), 7.66-7.70
(m, 4H, o-PPh2). 13C{1H} NMR (δ): 23.0, 27.5, 34.9, 119.0,
124.9, 127.5 (d, J C-P ) 12 Hz), 127.9, 128.9 (d, J C-P ) 13 Hz),
130.9 (d, J C-P ) 16 Hz), 131.0, 132.0 (d, J C-P ) 10 Hz), 132.0,
144.0 (J C-P ) 129 Hz), 146.2. 63: 92% yield, slightly yellow
Syn th esis of (L)NiBr 2 (69-75; L ) 61-67). Compounds
69-75 were prepared by similar methods; thus, only one
representative procedure is described. To a slight excess of 61
(1.05 equiv, 150 mg, 0.39 mmol) and NiBr2(DME) adduct (114
mg, 0.37 mmol) was added 10 mL of CH2Cl2. The blue
suspension was stirred overnight and concentrated in vacuo.
Et2O (10 mL) was added, and the mixture was filtered to give
a light blue powder. 69: 95% yield, purple powder, νPdN 1225
cm-1, µeff ) 3.01 µB. Anal. Calcd for C24H24Br2N3NiP (603.94):
C, 47.73; H, 4.01; N, 6.96. Found: C, 47.68; H, 4.00; N, 6.82.
70‚CH2Cl2: 90% yield, blue-green powder, νPdN 1214 cm-1, µeff
) 2.94 µB. Anal. Calcd for C29H34Br2Cl2N3NiP (744.98): C,
46.75; H, 4.60; N, 5.64. Found: C, 46.47; H, 4.44; N, 6.01. 71:
90% yield, purple powder, νPdN 1217 cm-1, µeff ) 2.99 µB. Anal.
Calcd for C36H32Br2N3NiP (756.13): C, 57.18; H, 4.27; N, 5.56.
Found: C, 56.83; H, 4.47; N, 5.33. 72: 87% yield, blue-green
solid, νPdN 1361 cm-1 31P{1H} NMR (δ): -16.6 (s). 1H NMR
.
(δ): 2.03 (s, 6H, Me), 3.46 (s, 3H, NMe), 6.92 (m, 1H, NAr H),
6.93 (d, 7 Hz, 2H, NAr H), 7.15-7.18 (m, 3H, Ar H), 7.31-
7.34 (m, 2H, Ar H), 7.46-7.55 (m, 11H, m-PPh2, p-PPh2, Ar
H), 7.89-7.95 (m, 4H, o-PPh2). 13C{1H} NMR (partial, δ): 20.2,
2
33.0, 119.1, 126.7, 127.9, 128.2 (d, J C-P ) 13 Hz), 128.5, 129.1,
129.2, 130.3, 130.8, 131.7, 132.4 (d, J C-P ) 10 Hz), 132.6, 134.3,
138.7 (d, J C-P ) 14 Hz), 142.5 (d, J C-P ) 128 Hz), 146.5. 64:
91% yield, cream-colored solid, νPdN 1372 cm-1 31P{1H} NMR
.
(δ): -16.3 (s).1H NMR (δ): 0.94 (d, 6.9 Hz, 12H, CHMe2), 3.32
(sept, 7 Hz, 2H, CHMe2), 3.44 (s, 3H, Me), 6.82 (dt, 7 Hz, 2
Hz, 1H, NAr H), 6.97 (m, 2H, NAr H), 7.13-7.27 (m, 3H, Ar
H), 7.30-7.33 (m, 2H, Ar H), 7.42-7.58 (m, 11H, m-PPh2,
p-PPh2, Ar H), 7.82-7.90 (m, 4H, o-PPh2). 13C{1H} NMR
(partial, δ): 23.7, 28.5, 32.8, 119.5, 122.7, 126.5, 126.8, 128.2
(d, J C-P ) 11.2 Hz), 128.4, 130.4 (d, J C-P ) 9 Hz), 130.6, 131.5,
powder, νPdN 1196 cm-1, µeff ) 3.15 µB. Anal. Calcd for C40H40
-
Br2N3NiP (812.24): C, 59.15; H, 4.96; N, 5.17. Found: C, 59.41;
H, 5.13; N, 5.01. 73‚CH2Cl2: 86% yield, purple powder, νPdN
1219 cm-1, µeff ) 3.41 µB. Anal. Calcd for C29H28Br2Cl2N3NiP
(738.93): C, 47.14; H, 3.82; N, 5.69. Found: C, 47.42; H, 3.66;
132.0, 132.4 (d, J C-P ) 10 Hz), 133.1, 134.4, 138.7 (d, J C-P
)
N, 5.84. 74: 87% yield, blue-green powder, νPdN 1243 cm-1
,
14 Hz), 141.7, 142.7 (d, J C-P ) 8 Hz), 142.9 (d, J CP 115 Hz),
µeff ) 3.24 µB. Anal. Calcd for C32H32Br2N3NiP (708.09): C,
54.28; H, 4.56; N, 5.93. Found: C, 54.57; H, 4.10; N, 5.81. 75:
91% yield, blue-green powder, νPdN 1244 cm-1, µeff ) 3.07 µB.
Anal. Calcd for C32H40Br2N3NiP (716.16): C, 53.67; H, 5.63;
N, 5.87. Found: C, 53.14; H, 5.44; N, 5.83.
143.3 (d, J C-P ) 13 Hz). 65: 88% yield, beige solid, νPdN 1362
1
cm-1
.
31P{1H} NMR (d8-THF, δ): -19.0 (s) H NMR (δ): 1.95
(s, 6H, Me), 3.83 (s, 3H, NMe), 6.49 (dt, 7.5, 1.5 Hz, 1H, NAr
H), 6.77 (d, 8 Hz, 2H, NAr H), 7.24-7.32 (m, 2H, benzimid),
7.41-7.52 (m, 7H, m-PPh2, p-PPh2, benzimid), 7.32 (d, 8 Hz,
1H, benzimid), 7.86-7.93 (m, 4H, o-PPh2). 13C{1H} NMR (δ):
21.1, 25.8, 32.1, 111.1, 119.6, 122.0, 123.5, 125.1, 128.7, 129.3
(d, J C-P ) 13 Hz), 132.5, 132.6, 133.2 (d, J C-P ) 10 Hz), 134.2,
138.1 (d, J C-P ) 3 Hz), 144.2 (d, J C-P ) 16 Hz), 147.5, 150.5
Syn th esis of (L)F eCl2 (76-82; L ) 61-67). Compounds
76-82 were prepared by similar methods; thus, only one
representative procedure is described. To a slight excess of 61
(150 mg, 0.39 mmol) and FeCl2 (47 mg, 0.37 mmol) was added
THF (10 mL). The orange suspension was stirred overnight
and was then concentrated in vacuo. Et2O (10 mL) was added,
and the mixture was filtered to give an orange powder. 76:
88% yield, orange solid, νPdN 1211 cm-1, µeff ) 4.98 µB. Anal.
Calcd for C24H24Cl2N3FeP (512.19): C, 56.28; H, 4.72; N, 8.20.
Found: C, 55.97; H, 4.80; N, 7.86. 77: 95% yield, yellow-orange
(d, J C-P ) 122 Hz). 66: 92% yield, cream-colored solid, νPdN
1
1370 cm-1
.
31P{1H} NMR (δ): -15.5 (s). H NMR (δ): 0.83 (d,
12 H, 7 Hz, CHMe2), 3.23 (sept, 2H, 7 Hz, CHMe2), 3.84 (s,
3H, NMe), 6.80-6.86 (m, 1H, NAr H), 6.95 (d, 2H, NAr H),
7.25-7.35 (m, 1H, benzimid), 7.40 (m, 2H, benzimid), 7.44-
7.50 (m, 4H, m-PPh2), 7.53-7.58 (m, 2H, p-PPh2), 7.73-7.80
(m, 4H, o-PPh2), 7.86 (m, 1H, benzimid). 13C{1H} NMR (δ):
23.6, 28.7, 31.6, 109.6, 119.8, 121.6, 122.7, 124.4, 128.6 (d, J C-P
) 12.9 Hz), 130.6 (d, J C-P ) 112 Hz), 132.3 (d, J C-P ) 10 Hz),
133.1, 133.9, 137.0, 142.6 (d, J C-P ) 7 Hz), 142.8, 143.4 (d,
J C-P ) 18 Hz), 150.7 (d, J C-P ) 121 Hz). 67: 90% yield, yellow
solid, νPdN 1198 cm-1, µeff ) 5.10 µB. Anal. Calcd for C28H32
Cl2N3FeP (568.30): C, 59.18; H, 5.68; N, 7.39. Found: C, 58.89;
H, 6.00; N, 7.43. 78: 84% yield, yellow crystals, νPdN 1217 cm-1
-
,
µeff ) 5.01 mB. Anal. Calcd for C36H32Cl2N3FeP (664.38): C,
65.08; H, 4.85; N, 6.32. Found: C, 64.91; H, 4.52; N, 5.82. 79‚
2CH2Cl2: 85% yield, yellow crystals, νPdN 1120 cm-1, µeff ) 4.99
µB. Anal. Calcd for C42H44Cl6FeN3P (890.35): C, 56.66; H, 4.98;
N, 4.72. Found: C, 56.55; H, 4.64; N, 4.93. 80: 89% yield,
orange solid, νPdN 1215 cm-1, µeff ) 5.24 µB. Anal. Calcd for
solid, νPdN 1377 cm-1 31P{1H} NMR (δ): -18.8 (s). 1H NMR
.
(δ): 0.85 (d, 12H, 7 Hz, CHMe2), 1.21 (s, 9H, Me), 3.25 (sept,
2H, CHMe2), 3.36 (s, 3H, NMe), 6.65 (s, 1H, imid), 6.80 (m,
1H, NAr H), 6.92 (m, 2H, NAr H), 7.37-7.40 (m, 4H, m-PPh2),
7.44 (m, 2H, p-PPh2), 7.76-7.80 (m, 4H, o-PPh2). 13C{H} NMR
C
28H26Cl2N3FeP (562.25): C, 59.81; H, 4.66; N, 7.47. Found:
C, 59.65; H, 5.06; N, 7.77. 81: 92% yield, yellow-orange solid,

Ethylene Oligomerization Catalysts
Organometallics, Vol. 22, No. 19, 2003 3847
νPdN 1191 cm-1, µeff ) 5.21 µB. Anal. Calcd for C32H34Cl2N3-
Ta ble 1. Com p ou n d Nu m ber in g: Liga n d s a n d Ni,
F e, a n d Co Com p lexes
FeP (618.36): C, 62.16; H, 5.54; N, 6.80. Found: C, 61.78; H,
5.85; N, 7.11. 82: 80% yield, yellow crystals, νPdN 1193 cm-1
,
µeff ) 5.12 µB. Anal. Calcd for C32H40Cl2N3FeP (624.40): C,
61.55; H, 6.46; N, 6.73. Found: C, 61.15; H, 6.38; N, 6.88.
P r oced u r e for Eth ylen e P olym er iza tion /Oligom er iza -
tion . A 500 mL Parr stainless steel autoclave equipped with
mechanical stirring and pressure gauge was heated (∼110 °C)
under vacuum for >2 h. The temperature of the autoclave was
regulated by a thermal jacket. The autoclave was cooled to
the desired temperature, and 500 equiv of MAO dissolved in
toluene was added under N2. The solution was stirred for an
additional 1 h, and a toluene suspension of the catalyst was
added. The vessel was then quickly pressurized with 300 psi
of ethylene, and the reaction mixture was stirred for 30 min.
The polymerization was stopped by venting the volatiles at
25 °C, followed by quenching of the reaction solution with
acidified MeOH, and the solution filtered. The organic layer
was separated, dried with Na2SO4, and filtered. The solvent
was removed to give traces of a sticky, gummy polymer. The
trace amounts of polymer were redissolved in hexane, the
solution was filtered again to remove any residual catalyst,
and the solvent was removed.
In the case of oligomerization, after reaction the autoclave
was cooled to -78 °C, and the volatiles were slowly vented.
EtOH (20 mL) and an internal standard were added (toluene
(DEAC activation) or Et2O (MAO activation)) to quench the
reaction, and the mixture was slowly warmed to -30 °C over
10 min. The composition of the alkenes formed was determined
by GC and NMR spectroscopy.
Com p u ta tion a l Deta ils. Optimized geometries of [(L)-
NiMe]+ (L ) diimine (NCCN), phosphinimine-imine (NPCN),
and fluorinated phosphinimine-imine (NPF2CN)) were ob-
tained using the Gaussian 9832 suite of programs. The hybrid
DFT method B3LYP (Becke, 1998, #63; as implemented in
G98) was employed in conjunction with the 6-31G(d) basis set
for the ligand and the LANL2DZ basis set for nickel. This
latter basis set uses the effective core potentials developed by
Hay and Wadt.33 NBO analysis was also performed on the
optimized structure to determine the natural charge on the
nickel atom. The optimized geometry of the Ni complex was
used to determine the orbital energies of the ligand. After the
Cartesian coordinates were determined for each optimized
structure, the nickel and methyl species were removed. A
single-point energy calculation was then performed on the
resulting constrained ligand geometries using the Hartree-
Fock (HF) method and the 6-31G(d) basis set to determine the
lone pair orbital energy. Lone pair diagrams were generated
using POV-ray.
X-r a y Da ta Collection a n d Red u ction . X-ray-quality
crystals were obtained directly from the preparations as
described above. The crystals were manipulated and mounted
in capillaries in a glovebox, thus maintaining a dry, O2-free
environment for each crystal. Diffraction experiments were
performed on a Siemens SMART System CCD diffractometer.
The data were collected for a hemisphere of data in 1329
frames with 10 s exposure times. Crystal data are summarized
in Table 2. The observed extinctions were consistent with the
(32) Frisch, M. J .; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J . R.; Zakrzewski, V. G.; Montgomery, J . A.
J .; Stratmann, R. E.; Burant, J . C.; Dapprich, S.; Millam, J . M.; Daniels,
A. D. K., K. N.; Strain, M. C.; Farkas, O.; Tomasi, J .; Barone, V.; Cossi,
M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo, C.; Clifford, S.;
Ochterski, J .; Petersson, G. A.; Ayala, P. Y.; Cui, Q.; Morokuma, K.;
Salvador, P.; Dannenberg, J . J .; Malick, D. K.; Rabuck, A. D.;
Raghavachari, K.; Foresman, J . B.; Cioslowski, J .; Ortiz, J . V.; Baboul,
A. G.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi,
I.; Gomperts, R.; Martin, R. L.; Fox, D. J .; Keith, T.; Al-Laham, M. A.;
Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.;
J ohnson, B.; Chen, W.; Wong, M. W.; Andres, J . L.; Gonzalez, C.; Head-
Gordon, M.; Replogle, E. S.; Pople, J . A. Gaussian 98; Gaussian, Inc.,
Pittsburgh, PA, 2001.
space groups in each case. A measure of decay was obtained
by re-collecting the first 50 frames of each data set. The
(33) Hay, P. J .; Wadt, W. R. J . Chem. Phys. 1985, 82, 270-283.

3848 Organometallics, Vol. 22, No. 19, 2003
Ta ble 2. Cr ysta llogr a p h ic P a r a m eter sa
Spencer et al.
2
20
26
27‚CH2Cl2
35
37
40‚H2O
formula
C
18H16NP
C20H23Cl2-
N2PPdSi
527.76
C
36H37Br2-
N2NiP
C
29H33Br2Cl2-
N2NiPSi
C
32H30Cl2-
FeN2P
C
28H31Cl2-
FeN2PSi
C
35H37Cl2-
FeN2OP
fw
277.29
747.18
758.06
600.30
581.36
659.39
a (Å)
b (Å)
c (Å)
11.076(7)
9.274(6)
15.069(10)
9.426(14)
15.17(2)
15.75(2)
90.83(3)
91.56(3)
90.18(3)
20.150(14)
9.089(6)
18.691(12)
10.109(6)
20.839(14)
15.184(9)
16.655(9)
20.504(11)
9.028(5)
8.807(4)
9.436(5)
18.571(9)
101.385(8)
98.601(9)
96.586(10)
9.019(5)
17.963(9)
21.636(11)
R (deg)
â (deg)
γ (deg)
cryst syst
space group
V (Å3)
102.377(14) 92.665(13)
99.174(10)
orthorhombic triclinic
monoclinic
P21/c
3344(4)
1.484
4
3.045
13 890
4819
monoclinic
P21/n
3195(4)
1.576
4
3.385
13 144
4564
orthorhombic triclinic
monoclinic
P21/c
3460(3)
1.266
4
0.665
14 566
4882
Pna21
1547.9(16)
1.190
4
0.167
6176
2130
181
0.0289
0.0639
0.702
P1h
Pna21
3083(3)
1.293
4
0.737
12 795
4326
P1h
2252(6)
1.556
4
1479.3(13)
1.305
2
D
Z
calcd (g cm-3
)
abs coeff, µ, mm-1
no. of data collected
no. of data with Fo2 > 3σ(Fo
no. of variables
R (%)
1.193
9555
6435
487
0.0262
0.0667
1.066
0.804
6296
4183
316
0.0339
0.1102
0.995
2
)
379
343
343
387
0.0573
0.1032
0.811
0.0790
0.2018
1.023
0.0552
0.1390
0.975
0.0410
0.1076
0.711
Rw (%)
goodness of fit
49
50
51‚H2O
54
68‚MeCN
79‚2CH2Cl2
82
formula
C
24H21Br2-
N2NiP
C
25H23Br2-
N2NiP
C
30H29Br2-
N2NiO2P
C
25H23Cl2-
CoN2P
C
30H32Cl2-
N4PPd
C
42H44Cl6-
FeN3P
C
32H40Cl2-
FeN3P
fw
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
cryst syst
space group
V (Å3)
586.93
600.95
699.04
512.26
656.87
10.333(8)
11.302(8)
13.339(10)
73.674(14)
87.098(13)
85.621(14)
triclinic
P1h
890.32
624.39
9.272(6)
13.665(8)
19.814(12)
8.090(4)
19.942(10)
15.744(8)
12.238(7)
11.229(6)
22.877(13)
20.261(11)
15.214(8)
16.155(9)
16.006(9)
18.784(11)
16.330(9)
12.376(6)
15.765(8)
17.919(8)
101.227(10)
96.610(9)
101.244(11)
99.234(10)
113.890(11)
109.685(9)
monoclinic
P21/c
2462(3)
1.583
4
4.111
10 362
3505
monoclinic
P21/c
2523(2)
1.582
4
4.014
10 676
3595
monoclinic
P2(1)
3083(3)
1.467
4
3.297
13 500
8248
monoclinic
C2/c
4915(5)
1.384
8
0.996
10 443
3521
monoclinic
P21/n
4489(4)
1.317
4
0.761
18 964
6369
monoclinic
P21/c
3292(3)
1.260
4
0.694
13 829
4674
1490.0(19)
1.464
D
Z
calcd (g cm-3
)
2
abs coeff, µ, mm-1
0.882
6265
4278
343
0.0431
0.1046
1.004
no. of data collected
no. of data with Fo2 > 3σ(Fo
no. of variables
R (%)
)
2
271
280
673
280
478
352
0.0286
0.0807
0.338
0.0301
0.0730
0.985
0.0612
0.1486
0.927
0.0290
0.0586
0.820
0.0519
0.1396
0.978
0.0311
0.0841
1.005
Rw (%)
goodness of fit
All data were collected at 24 °C with Mo KR radiation (λ ) 0.710 69 Å), R ) ∑||Fo| - |Fc||/ ∑|Fo|, Rw ) [∑[w(Fo - Fc2)2]/∑[w(Fo2)2]]0.5
.
a
2
intensities of reflections within these frames showed no
statistically significant change over the duration of the data
collections. An empirical absorption correction based on re-
dundant data was applied to each data set. Subsequent
solution and refinement was performed using the SHELXTL
solution package.
carbon atom to which they are bonded. The hydrogen atom
contributions were calculated but not refined. The final values
of refinement parameters are given in Table 2. Positional
parameters, hydrogen atom parameters, thermal parameters,
and bond distances and angles have been deposited as
Supporting Information.
St r u ct u r e Solu t ion a n d R efin em en t . Non-hydrogen
atomic scattering factors were taken from the literature
tabulations.34 The heavy-atom positions were determined using
direct methods. The remaining non-hydrogen atoms were
located from successive difference Fourier map calculations.
The refinements were carried out by using full-matrix least-
squares techniques on F, minimizing the function w(Fo - Fc)2,
where the weight w is defined as 4Fo2/2σ(Fo2) and Fo and Fc
are the observed and calculated structure factor amplitudes.
For noncentrosymmetric space groups, the correct enantio-
morph was confirmed by data inversion and refinement. In
the final cycles of each refinement, all non-hydrogen atoms
were assigned anisotropic temperature factors. Carbon-bound
hydrogen atom positions were calculated and allowed to ride
on the carbon to which they are bonded, assuming a C-H bond
length of 0.95 Å. Hydrogen atom temperature factors were
fixed at 1.10 times the isotropic temperature factor of the
Resu lts a n d Discu ssion
P yr id in e-P h osp h in im in e (En d ocyclic P ) Liga n d
Com p lexes. A series of 2-substituted diphenylphos-
phine pyridines were synthesized in reasonable yields
by the reaction of LiPPh2 with the appropriately sub-
stituted bromopyridine precursor (Scheme 1). The1H
NMR spectra of 1-6 showed the expected resonances
with 31P resonances around -3.5 ppm. In the case of 4,
X-ray crystallography confirmed the formulation (Figure
1). As expected, the geometry at the phosphorus atom
is pseudo-tetrahedral with angles about P(1) ranging
from 100.64(17) to 102.41(16)°, comparable to those
previously reported for 1.35
Substituted phenyl azides were synthesized, employ-
ing a modification of the published method.31 The
(34) Cromer, D. T.; Mann, J . B. Acta Crystallogr., Sect. A 1968, A24,
321-324.
(35) Dunne, B. J .; Orpen, A. G. Acta Crystallogr., Sect. C 1991, C47,
345-347.

Ethylene Oligomerization Catalysts
Organometallics, Vol. 22, No. 19, 2003 3849
F igu r e 1. ORTEP drawing of 2, with 30% thermal
ellipsoids. H atoms have been omitted for clarity. Bond
lengths (Å) and angles (deg): P(1)-C(1) ) 1.846(2), P(1)-
C(7) ) 1.846(3), P(1)-C(13) ) 1.850(3); C(1)-P(1)-C(7) )
102.29(12), C(1)-P(1)-C(13) ) 100.90(12), C(7)-P(1)-
C(13) ) 100.94(12).
F igu r e 2. ORTEP drawing of one of the two molecules in
the asymmetric unit of 20, with 30% thermal ellipsoids.
Hydrogen atoms have been omitted for clarity. Bond
lengths (Å) and angles (deg): Pd(1)-N(2) ) 2.056(4),
Pd(1)-N(1) ) 2.062(3), Pd(1)-Cl(2) ) 2.280(2), Pd(1)-
Cl(1) ) 2.286(3), Pd(1)-P(1) ) 2.873(3), P(1)-N(1) )
1.578(3), N(1)-Si(1) ) 1.752(3); N(2)-Pd(1)-N(1) )
85.17(12), N(2)-Pd(1)-Cl(2) ) 93.15(10), N(1)-Pd(1)-Cl-
(2) ) 176.24(8), N(2)-Pd(1)-Cl(1) ) 172.36(8), N(1)-Pd-
(1)-Cl(1) ) 92.64(11), Cl(2)-Pd(1)-Cl(1) ) 89.45(9), N(2)-
Pd(1)-P(1) ) 61.81(12), N(1)-Pd(1)-P(1) ) 32.30(8), Cl(2)-
Pd(1)-P(1) ) 148.47(4), Cl(1)-Pd(1)-P(1) ) 113.15(11),
Sch em e 1
P(1)-N(1)-Si(1)
)
134.77(16), P(1)-N(1)-Pd(1)
)
103.42(14), Si1 N(1)-Pd(1) ) 121.81(15).
confirmed crystallographically. The geometry about Pd
is pseudo square planar, with the pyridine-phosphin-
imine ligand coordinating in a bidentate fashion (Figure
2). The palladium-phosphinimine five-membered met-
allacycle is not planar, with a torsion angle formed by
Pd(1)-N(2)-C(13)-P(1) of 4.3° and a mean deviation
from the plane of 0.0847 Å. Such a distortion is not
surprising, as Arques et al. have described this phe-
nomenon for related complexes.42 The Pd-Cl bond
lengths (2.286(3), 2.280(2) Å), while chemically distinct,
are very similar, suggesting that the trans influences
of the two differing N-atom donors are similar. The Pd-
phosphinimine N atom (Pd-NPhos) bond is similar to
those previously described for related Pd complexes of
P,N-chelated phosphinimine ligands.42,43 Although the
P-N bond is slightly longer in 20 (1.578(3) Å) than that
previously published syntheses17,36 of 2,6-di-isopropyl-
phenyl azide suffers from low yields and impurities. The
method described herein involves the isolation of the
air-stable diazonium tetrafluoroborate salt and subse-
quent nucleophilic reaction with azide to form 7 and 8
in yields greater than 85% yield, with only trace
amounts of impurities. Oxidation of the phosphines 1-5
with 7, 8, or Me3SiN3 proceeded cleanly to give the series
of phosphinimine derivatives 9-19 in excellent yields.
These phosphinimine derivatives result in the observed
downfield shift of the 31P resonance to 5-10 ppm. The
IR spectra of 9-19 were consistent with the presence
of the P-N bonds with stretching frequencies ranging
from 1329 to 1357 cm-1, in agreement with previous
results.37-40 In an analogous method, attempts to oxi-
dize the fluorinated phosphine 2-P(C6F5)26-PhC5H3N (6)
were unsuccessful, despite the use of elevated temper-
atures. Similar difficulties with the oxidation of analo-
gous pyrrolyl and indolyl phosphines have been previ-
ously reported.41
14
reported for the free ligand CH2(Ph2P-NC6H4Me-4)2
(1.568(2) Å), this distance is typical of a highly polarized
P-N bond.
Similarly, the Ni(II) and Fe(II) complexes 21-30 and
31-40, respectively, were synthesized from the reaction
between the ligands 10-19 and the corresponding metal
halides (Table 1). The formulations of these metal
complexes were supported by IR spectroscopy, magnetic
susceptibility, elemental analysis, and X-ray crystal-
lography. IR spectroscopy of these complexes showed
νPdN bands between 1190 and 1250 cm-1, which were
about 100 cm-1 lower than those for the free ligands.4,5
This suggests a slightly less polar P-N double-bond
character upon ligand coordination, consistent with
Reaction of the ligand 9 and PdCl2(PhCN)2 gives the
square-planar, diamagnetic compound 20, which can be
identified by NMR spectroscopy. The 1H NMR spectrum
of complex 20 shows very little shift in the ligand
resonances upon coordination to Pd; however, the 31P
NMR resonance displays the expected significant down-
field shift of ca. 30 ppm. The formulation of 20 was also
(36) Smolinsky, G. J . Org. Chem. 1961, 26, 4108-4110.
(37) King, R. B.; Cloyd, J . C., J r. Inorg. Chem. 1975, 14, 1550-1554.
(38) Hietkamp, S.; Stufkens, D. J .; Vrieze, K. J . Organomet. Chem.
1979, 169, 107-113.
(39) MacLeod, I.; Manojlovic-Muir, L.; Millington, D.; Muir, K. W.;
Sharp, D. W. A.; Walker, R. J . Organomet. Chem. 1975, 97, C7-C10.
(40) Appleton, T. G.; Bennett, M. A. Inorg. Chem. 1978, 17, 738-
747.
(42) Arques, A.; Molina, P.; Aunon, D.; Vilaplana, M. J .; Velasco,
M. D.; Martinez, F.; Bautista, D.; Lahoz, F. J . J . Organomet. Chem.
2000, 598, 329-338.
(43) Liu, C.-Y.; Chen, D.-Y.; Cheng, M.-C.; Peng, S.-M.; Liu, S.-T.
Organometallics 1995, 14, 1983-1991.
(44) Moore, S. S.; Whitesides, G. M. J . Org. Chem. 1982, 47, 1489-
1493.
(41) Ali, R.; Dillon, K. B. J . Chem. Soc., Dalton Trans. 1990, 2593-
2596.
(45) Abdul J alil, M.; Yamada, T.; Fujinami, S.; Honjo, T.; Nishikawa,
H. Polyhedron 2001, 20, 627-633.

3850 Organometallics, Vol. 22, No. 19, 2003
Spencer et al.
F igu r e 3. ORTEP drawings of (a) 35 and (b) 26, with 30%
thermal ellipsoids. Hydrogen atoms have been omitted for
clarity. Bond lengths (Å) and angles (deg) for 35: Fe(1)-
N(2) ) 2.053(6), Fe(1)-N(1) ) 2.184(5), Fe(1)-Cl(2) )
2.317(2), Fe(1)-Cl(1) ) 2.325(2), P(1)-N(2) ) 1.608(6);
F igu r e 4. ORTEP drawings of (a) 27 and (b) 37, with 30%
thermal ellipsoids. Hydrogen atoms have been omitted for
clarity. Bond lengths (Å) and angles (deg) for 27: Ni(1)-
N(1) ) 1.996(8), Ni(1)-N(2) ) 2.092(8), Ni(1)-Br(1) )
2.379(2), Ni(1)-Br(2) ) 2.395(2), P(1)-N(1) ) 1.586(9);
N(1)-Ni(1)-N(2) ) 88.4(3), N(1)-Ni(1)-Br(1) ) 106.0(2),
N(2)-Ni(1)-Br(1) ) 139.4(2), N(1)-Ni(1)-Br(2) ) 113.7-
(2), N(2)-Ni(1)-Br(2) ) 100.6(2), Br(1)-Ni(1)-Br(2) )
107.36(7), P(1)-N(1)-Ni(1) ) 115.2(4). Bond lengths (Å)
and angles (deg) for 37: Fe(1)-N(2) ) 2.048(2), Fe(1)-N(1)
) 2.192(2), Fe(1)-Cl(2) ) 2.2451(11), Fe(1)-Cl(1) )
2.2737(10), P(1)-N(2) ) 1.600(2); N(2)-Fe(1)-N(1) )
85.46(8), N(2)-Fe(1)-Cl(2) ) 114.96(7), N(1)-Fe(1)-
Cl(2) ) 113.99(6), N(2)-Fe(1)-Cl(1) ) 106.80(6), N(1)-
Fe(1)-Cl(1) ) 111.61(6), Cl(2)-Fe(1)-Cl(1) ) 119.03(5),
P(1)-N(2)-Fe(1) ) 116.87(11).
N(2)-Fe(1)-N(1)
)
84.3(2), N(2)-Fe(1)-Cl(2)
)
116.93(17), N(1)-Fe(1)-Cl(2) ) 113.84(16), N(2)-Fe(1)-
Cl(1) ) 112.01(17), N(1)-Fe(1)-Cl(1) ) 108.07(17), Cl(2)-
Fe(1)-Cl(1) ) 116.97(8), P(1)-N(2)-Fe(1) ) 116.8(3), Bond
lengths (Å) and angles (deg) for 26: Ni(1)-N(2) )
1.999(7), Ni(1)-N(1) ) 2.062(7), Ni(1)-Br(1) ) 2.355(2),
Ni(1)-Br(2) ) 2.4006(19), P(1)-N(2) ) 1.613(7); N(2)-
Ni(1)-N(1) ) 87.6(3), N(2)-Ni(1)-Br(1) ) 120.4(2), N(1)-
Ni(1)-Br(1) ) 126.1(2), N(2)-Ni(1)-Br(2) ) 116.5(2),
N(1)-Ni(1)-Br(2)
) 102.0(2), Br(1)-Ni(1)-Br(2) )
103.51(7), P(1)-N(2)-Ni(1) ) 114.2(4).
X-ray data (vide infra). Magnetic susceptibility mea-
surements showed average typical values of 5.13 µB for
Fe(II) complexes and 3.04 µB for Ni(II) complexes.
In addition to these data, X-ray structure determina-
tions were obtained for 26, 27, 35, 37, and 40 (Figures
3-5). The geometries about the metal atoms in these
species are pseudo-tetrahedral, with two halides and a
bidentate pyridine-phosphinimine ligand completing
the coordination sphere. In all of these compounds the
aryl ring on the N, as a result of the 2,6-substitution, is
oriented approximately orthogonal to the ligand plane,
a feature that has been shown to favor catalytic activity
in related systems. The Ni-Br distances in 26 and 27
were similar, falling in the range from 2.355(2) to
2.4006(19) Å. In contrast, the Fe-Cl distances in 35
were 2.317(2) and 2.325(2) Å, which were significantly
shorter than those found in 37 (2.2451(11), 2.2737(10)
Å) and 40 (2.2668(16), 2.2754(15) Å). This difference
may be attributed to the increasing steric effects of the
SiMe3 substituent on the pyridine ring. Of the two types
of M-N bonds, the M-pyridine bond was consistently
longer than the corresponding M-phosphinimine bond.
For example, in 35 the Fe-Npy bond was found to be
2.184(5) Å, whereas the Fe-NPhos bond was found to be
2.053(6) Å. Such differences are also amplified by
sterically demanding substitution on the pyridine ring.
In 37, the difference between Fe-Npy and Fe-NPhos
increases to 0.144 Å in Fe-NPhos, whereas in 40 this
difference is further increased to 0.162 Å. Similarly, the
F igu r e 5. ORTEP drawing of 40, with 30% thermal
ellipsoids. Hydrogen atoms have been omitted for clarity.
Bond lengths (Å) and angles (deg): Fe(1)-N(1)
)
2.067(3), Fe(1)-N(2) ) 2.229(3), Fe(1)-Cl(2) ) 2.2668(16),
Fe(1)-Cl(1) ) 2.2754(15), P(1)-N(1) ) 1.602(3); N(1)-
Fe(1)-N(2) ) 82.93(13), N(1)-Fe(1)-Cl(2) ) 110.22(10),
N(2)-Fe(1)-Cl(2)
) 125.71(10), N(1)-Fe(1)-Cl(1) )
119.09(10), N(2)-Fe(1)-Cl(1) ) 104.78(10), Cl(2)-Fe(1)-
Cl(1) ) 112.02(6), P(1)-N(1)-Fe(1) ) 116.07(18).
Ni-Npy and Ni-NPhos distances in 26 were found to be
2.062(7) and 1.999(7) Å, respectively; whereas in 27, the
corresponding distances are 2.092(8) and 1.996(8) Å.
This again reflects the increased steric demand of SiMe3
versus a benzyl group. The P-N bond lengths in these
compounds varied between 1.586(9) and 1.613(7) Å,
which is typical of coordinated phosphinimine ligands.46
For example, Elsevier et al. reported similar P-N

Ethylene Oligomerization Catalysts
Organometallics, Vol. 22, No. 19, 2003 3851
F igu r e 6. ORTEP drawing of 49, with 30% thermal
ellipsoids. Hydrogen atoms have been omitted for clarity.
Bond lengths (Å) and angles (deg): Ni(1)-N(2)
)
1.976(5), Ni(1)-N(1) ) 1.977(4), Ni(1)-Br(2) ) 2.3611(16),
Ni(1)-Br(1) ) 2.3832(13), P(1)-N(1) ) 1.615(5); N(2)-
Ni(1)-N(1) ) 83.69(19), N(2)-Ni(1)-Br(2) ) 108.59(14),
N(1)-Ni(1)-Br(2)
) 119.16(13), N(2)-Ni(1)-Br(1) )
102.79(15), N(1)-Ni(1)-Br(1) ) 125.10(14), Br(2)-Ni(1)-
Br(1) ) 110.16(4), P(1)-N(1)-Ni(1) ) 129.6(2).
Sch em e 2
F igu r e 7. ORTEP drawings of (a) 50 and (b) 54, with 30%
thermal ellipsoids. Hydrogen atoms have been omitted for
clarity. Bond lengths (Å) and angles (deg) for 50: Ni(1)-
N(1) ) 1.983(3), Ni(1)-N(2) ) 2.008(3), Ni(1)-Br(1) )
2.3825(12), Ni(1)-Br(2)
) 2.3875(11), P(1)-N(1) )
1.609(3); N(1)-Ni(1)-N(2) ) 84.13(11), N(1)-Ni(1)-Br(1)
) 113.72(9), N(2)-Ni(1)-Br(1) ) 111.91(9), N(1)-Ni(1)-
Br(2) ) 115.90(9), N(2)-Ni(1)-Br(2) ) 104.98(9), Br(1)-
Ni(1)-Br(2) ) 119.82(3), P(1)-N(1)-Ni(1) ) 128.28(16).
Bond distances (Å) and angles (deg) for 54: Co(1)-N(1) )
1.989(2), Co(1)-N(2) ) 2.053(2), Co(1)-Cl(2) ) 2.2327(11),
Co(1)-Cl(1) ) 2.2663(12), N(1)-C7 ) 1.471(3), N(1)-P(1)
) 1.601(2); N(1)-Co(1)-N(2) ) 83.72(9), N(1)-Co(1)-
Cl(2) ) 113.19(7), N(2)-Co(1)-Cl(2) ) 116.99(8), N(1)-
Co(1)-Cl(1) ) 120.52(7), N(2)-Co(1)-Cl(1) ) 103.51(7),
distances in the complex [(CH2(Ph2PN(4-MeC6H4)2Rh-
(COD)].14 The NPCNM five-membered chelate rings are
distorted from planar orientations. Atom displacements
from the mean planes are relatively small, with the
maximum being 0.1026 Å for 40. Such distortions arise
presumably to minimize steric interactions of the pyri-
dine substituents with the metal center.
Cl(2)-Co(1)-Cl(1)
) 114.70(4), P(1)-N(1)-Co(1) )
P yr id in e-P h osp h in im in e (Exocyclic P ) Liga n d
Com p lexes. A second strategy to related pyridine-
phosphinimine ligands involved the use of a series of
2-(azidomethyl)pyridines, which were prepared from
known precursors. These compounds were then used to
oxidize PPh3, affording the ligands 2-(Ph3PNCH2)-
(C5H4N) (44), 2-(Ph3PNCH2)-6-Me(C5H3N) (45), and
2-(Ph3PNCH2)-6-Ph(C5H3N) (46) in yields ranging from
55 to 86% (Scheme 2). The NMR spectra of 44-46
128.72(12).
1
showed the expected H resonances, and the 31P signals
were all approximately 7.8 ppm.
By methods similar to those described above, a series
of metal complexes of these pyridine-phosphinimine
ligands with exocyclic phosphine groups were prepared.
Complexes of (L)PdCl2 (47, 48; L ) 44, 45) were
prepared and characterized spectroscopically. As was
F igu r e 8. ORTEP drawing of one of the two molecules of
51 in the asymmetric unit, with 30% thermal ellipsoids.
Hydrogen atoms have been omitted for clarity. Bond
lengths (Å) and angles (deg): Ni(1)-N(2) ) 2.008(10),
Ni(1)-N(1) ) 2.007(10), Ni(1)-Br(1) ) 2.363(2), Ni(1)-
Br(2) ) 2.417(2), P(1)-N(1) ) 1.572(10); N(2)-Ni(1)-N(1)
) 85.2(4), N(2)-Ni(1)-Br(1) ) 106.4(3), N(1)-Ni(1)-
Br(1) ) 113.0(3), N(2)-Ni(1)-Br(2) ) 107.4(3), N(1)-
Ni(1)-Br(2) ) 102.0(3), Br(1)-Ni(1)-Br(2) ) 132.58(9),
N(1)-P(1)-C(13) ) 114.8(6), P(1)-N(1)-Ni(1) ) 131.6(7).
1
the case for 20, H NMR data revealed minor changes
while the 31P NMR spectrum revealed a substantial
shift upon coordination to the metal center. Similarly,
the Ni, Fe, and Co complexes (L)NiBr2 (49-51; L ) 44-
46), (L)FeCl2 (52, 53; L ) 44, 45), and (L)CoCl2 (54, 55;
L ) 44, 45) were prepared. X-ray structural data were
obtained for the pseudo-tetrahedral compounds 49-51
and 54 (Figures 6-8). For the Ni complex 49, the
Ni-Br distances are similar to those above, all ranging
from 2.3611(16) to 2.417(2) Å. The P-N bond lengths
in 49-51 ranged from 1.572(10) to 1.615(5) Å, which
are also similar to those found in 20, 26, 27, 35, 37, and
40. In contrast to the endocyclic P-ligand complexes,
these species exhibit Ni-Npy and Ni-NPhos bond lengths
(46) Tolmachev, A. A.; Yurchenko, A. A.; Semenova, M. G.; Fesh-
chenko, N. G. Zh. Obshch. Khim. 1993, 63, 714-716.

3852 Organometallics, Vol. 22, No. 19, 2003
Spencer et al.
Sch em e 3
that are very similar (49, 1.976(5), 1.977(4) Å; 50,
1.983(3), 2.008(3) Å; 51, 2.008(10), 2.007(10) Å). In
addition, the Co analogue of 50, 54, was also character-
ized. The geometry of this species is indeed similar to
that of the Ni species, with average Co-Cl distances of
2.2545(13) Å and Co-Nphos and Co-Npy distances of
1.989(2) and 2.053(2) Å, respectively. These structural
data reveal that both the electronic and steric changes
to the ligand geometry of these ligands with exocyclic
phosphine fragments appear to reduce steric congestion
at the metal center, allowing strong interactions with
the donor atoms. In the case of 51 in particular, we note
that the angle between the planes of the pyridine ring
and the phenyl substituent is 45.3°. This substituent,
together with the exocyclic phosphine group, appears
to create a “protective pocket” for the metal center, a
feature that augurs well for applications in catalysis.
Im id a zole-P h osp h in im in e Liga n d Com p lexes.
Of the known methods for the synthesis of imidazolyl-
phosphines,44-46 the most convenient route involves the
selective lithiation of the C2 position of the imidazole
followed by reaction with PPh2Cl. In this manner, the
imidazolyl-phosphines 2-(PPh2)C3H3N2 (56),28 1-Me-2-
(PPh2)-4-(t-Bu)C3HN2 (57),47,48 1-Me-2-(PPh2)C3H2N2
(58), 1-Me-2-(PPh2)-4,5-Ph2C3N2 (59) and 1-Me-2-(PPh2)-
C7H6N2 (60) were synthesized and isolated in greater
than 75% yield. 31P NMR spectroscopy reveals chemical
shifts for these species between -25 and -30 ppm.
Subsequent oxidation with substituted phenyl azides
provides imidazolyl-phosphinimine ligands in excellent
yields after recrystallization (Scheme 3). 1H and 31P
NMR spectroscopy were consistent with these formula-
tions, and IR data revealed the typical PN stretching
F igu r e 9. ORTEP drawing of one of the two molecules of
68 in the asymmetric unit, with 30% thermal ellipsoids.
Hydrogen atoms have been omitted for clarity. Bond
lengths (Å) and angles (deg): Pd(1)-N(2) ) 2.026(4),
Pd(1)-N(1) ) 2.086(4), Pd(1)-Cl(1) ) 2.297(2), Pd(1)-Cl-
(2) ) 2.2987(17), P(1)-N(1) ) 1.614(4); N(2)-Pd(1)-N(1)
) 84.69(14), N(2)-Pd(1)-Cl(1) ) 175.56(11), N(1)-Pd(1)-
Cl(1) ) 93.75(11), N(2)-Pd(1)-Cl(2) ) 90.91(11), N(1)-
Pd(1)-Cl(2) ) 175.33(11), Cl(1)-Pd(1)-Cl(2) ) 90.75(5),
P(1)-N(1)-Pd(1) ) 117.01(19).
In contrast to the pyridine based ligand systems the
Pd-NPhos bond length of 2.026(4) Å is slightly shorter
than the Pd-NImid length of 2.086(4) Å. However, the
Pd-Cl distances are similar at 2.297(2) and 2.2987(17)
Å. The five-membered chelate ring is almost planar,
with an average deviation from the mean plane of
0.0178 Å. The P-N bond length in 68 of 1.614(4) Å is
longer than that seen in 20 (1.578(3) Å), suggesting that
presence of the imidazole fragment also has an elec-
tronic effect on the phosphinimine fragment.
Fe(II) and Ni(II) complexes of these imidazole-
phosphinimine ligands were synthesized, affording com-
pounds 69-75 and 76-82, respectively. These para-
magnetic complexes were not soluble in common organic
solvents. IR spectroscopy of 69-82 showed typical PN
stretching frequencies between 1190 and 1250 cm-1
,
while the magnetic susceptibility measurements of the
Ni and Fe complexes of 3.12 and 5.09 µB, respectively,
were also typical of pseudo-tetrahedral Ni(II) and
Fe(II).
X-ray structural determinations of 79 and 82 (Figure
10) confirmed pseudo-tetrahedral geometries with two
Cl atoms and the bidentate imidazole-phosphinimine
ligand completing the coordination sphere. The Fe-Cl
distances in 79 (2.2590(17), 2.2845(15) Å) and 82
(2.2532(14), 2.2790(11) Å) are markedly shorter than
those found in 35 but similar to those found in 37 and
40. The difference in the two types of Fe-N bonds was
found to be relatively small (79, Fe-NPhos ) 2.104(3)
Å, Fe-NImid ) 2.114(4) Å; 82, Fe-NPhos ) 2.097(2) Å,
Fe-NImid ) 2.140(2) Å) compared to that in the pyri-
dine-phosphinimine complexes above. This suggests
that the donors in imidazole-phosphinimine ligands are
electronically similar to those in the pyridine-phos-
phinimine analogues. The P-N distances in both 79 and
82 were similar, averaging 1.599(3) Å, typical of P-N
bond lengths in such compounds. The phenyl substitu-
ents in 79 are canted at an angle of 49.1° with respect
to the imidazole ring, similar to that observed for the
phenyl substituent in 40. The presence of this phenyl
ring in 79 or the t-Bu group in 82 in the 4-position also
frequencies in the range of 1352-1377 cm-1
.
The reaction between compound 62 and (PhCN)2PdCl2
proceeds to form (1-Me-2-(2,6-i-Pr2C6H3NPPh2)(C3H2N2))-
PdCl2 (68). 31P NMR spectroscopy shows a singlet at
28.2 ppm, consistent with the expected downfield coor-
1
dination shift. H NMR spectrum of 68 showed small
chemical shift differences compared to the free ligand,
with the exception of the observation of two resonances
attributable to chemically inequivalent isopropyl methyl
groups. Similarly, these methyl groups give rise to
inequivalent 13C NMR resonances at 22.5 and 25.1 ppm.
Similar observations have been made in related Pd-
diimine complexes reported by Brookhart.4,5
The X-ray structure of 68 reveals that the imidazole-
phosphinimine ligand coordinates in a bidentate fashion
with a pseudo-square-planar geometry at Pd (Figure 9).
(47) Lipshutz, B. H.; Morey, M. C. J . Org. Chem. 1983, 48, 3745-
3750.
(48) Hilf, C.; Bosold, F.; Harms, K.; Lohrenz, J . C. W.; Marsch, M.;
Schimeczek, M.; Boche, G. Chem. Ber. 1997, 130, 1201-1212.

Ethylene Oligomerization Catalysts
Organometallics, Vol. 22, No. 19, 2003 3853
Ta ble 3. Eth ylen e Dim er iza tion
precatalyst solvent C4 oligomer (g)c activityd 1-C4H8:2-C4H8
30a
30b
40a
40b
74
74
82
82
MeC6H5
ClC6H5
MeC6H5
ClC6H5
MeC6H5
ClC6H5
MeC6H5
ClC6H5
0.807
7.95
0.66
0.50
0.52
2.98
0.10
0.35
16.1
48.2
13.2
3.0
10.3
17.9
2.0
1:99
1:99
1:99
1:99
1:99
86:13
1:99
1:99
2.1
a
Conditions: 300 psig of ethylene, 35 °C, Al:M ratio of 500:1,
b
MAO. Conditions: 300 psig of ethylene, 35 °C, Et2AlCl, Al:M
ratio of 200:1. c Calculated from GC and NMR data. In units of
d
g of oligomer (g of cat.)-1 h-1 atm-1
.
Of these, the Ni catalyst generated from 30/Et2AlCl gave
the highest activity (Table 3). GC and NMR data
confirmed the products were 1- and 2-butenes, 2-butene
being the major product in most cases. Only for 74 in
chlorobenzene did NMR and GC analysis show 1-butene
as the predominant product, with minor amounts of cis-
and trans-butene. The reason for the reversal in selec-
tivity is unclear, although the selective production of
1-butene is similar to that observed by Sun et al. for a
P,N-chelated Ni catalyst.49 Nonetheless, it is noteworthy
that the present systems exhibited much lower dimer-
ization activity. Similarly, catalysts derived from Ni-
bis(phosphinimine) complexes and Et2AlCl produced
primarily C4 alkenes with smaller amounts of C6 and
C8 alkenes,18 although those catalysts as well as other
known dimerization and oligomerization catalysts2 ex-
hibited significantly higher activity than the present
systems.
Com p u ta tion a n d Liga n d Con sid er a tion s. On the
basis of DFT studies of cationic nickel-diimine com-
plexes50-59 Tomita et al. have suggested that σ-donation
of ethylene participates in the coordinate nickel bond
to a greater extent than π-back-donation59 and that the
degree of σ-donation by ethylene will be influenced by
the trans-coordinated ligand. Furthermore, the energy
of the lone pair of electrons on the trans-donor ligand
reflects its trans influence; thus, the greater the energy
of the lone pair orbital, the more electron donating the
ligand is to the metal center. DFT calculations of the
orbital energies for the ligand models of HNCHCHNH,
HNPH2CHNH, and HNCHCH2NPH3 (Chart 1) showed
that HOMO-1 and the HOMO-2 correspond to the lone
pairs of the imine and phosphinimine fragments, re-
spectively. The results (Table 4) indicate that the
presence of a P atom in the ligand backbone increases
F igu r e 10. ORTEP drawings of (a) 79 and (b) 82, in the
asymmetric unit, with 30% thermal ellipsoids. Hydrogen
atoms have been omitted for clarity. Bond lengths (Å) and
angles (deg) for 79: Fe(1)-N(1) ) 2.104(3), Fe(1)-N(2) )
2.114(4), Fe(1)-Cl(2)
)
2.2590(17), Fe(1)-Cl(1)
)
2.2845(15), P(1)-N(1) ) 1.600(3); N(1)-Fe(1)-N(2) )
84.76(12), N(1)-Fe(1)-Cl(2) ) 127.04(10), N(2)-Fe(1)-
Cl(2) ) 108.12(9), N(1)-Fe(1)-Cl(1) ) 105.14(10), N(2)-
Fe(1)-Cl(1) ) 110.33(10), Cl(2)-Fe(1)-Cl(1) ) 116.49(6),
P(1)-N(1)-Fe(1) ) 115.89(18). Bond distances (Å) and
angles (deg) for 82: Fe(1)-N(1) ) 2.097(2), Fe(1)-N(2) )
2.140(2), Fe(1)-Cl(1)
)
2.2790(11), Fe(1)-Cl(2)
)
2.2532(14), N(1)-P(1) ) 1.598(2); N(1)-Fe(1)-N(2) )
85.07(7), N(1)-Fe(1)-Cl(2) ) 117.48(6), N(2)-Fe(1)-
Cl(2) ) 115.53(6), N(1)-Fe(1)-Cl(1) ) 109.92(7), N(2)-
Fe(1)-Cl(1) ) 109.31(6), Cl(2)-Fe(1)-Cl(1) ) 115.60(4),
P(1)-N(1)-Fe(1) ) 114.61(10).
forms what appears to be a protected pocket around the
metal center similar to those seen in the substituted
pyridine-phosphinimine ligand complexes above.
Eth ylen e Oligom er iza tion . Complexes 27-30, 37-
40, 74, 75, and 82 were initially screened for activity
as catalyst precursors for ethylene polymerization. A
500 equiv amount of MAO or MMAO was employed as
the activator in either toluene or hexane at 35 °C under
300 psi of ethylene in a Parr high-pressure reactor. In
general, these tests yield no isolable polymer; however,
in the case of MMAO activation of 74, polyethylene of
molecular weight 23 100 (PDI 1.34) was obtained. In
this case, although the PDI implies a single-site catalyst,
the activity of the catalyst was low (3.6 g of PE (mmol
of cat.)-1 h-1 atm-1). In several cases some ethylene
consumption was evident, suggesting that ethylene
oligomerization may be occurring. On the basis of the
findings in related late-metal catalyst systems, the
complexes with increased steric bulk adjacent to the
metal center, 30, 40, 74, and 82, were examined in
further detail. In these cases, the catalyst was generated
in situ via activation with either MAO (toluene) or Et2-
AlCl (ClC6H5) at 35 °C under 300 psi of ethylene. Under
these reaction conditions, these compounds yielded only
modest catalytic activity. In general, the Fe(II) com-
plexes exhibited lower activity than the Ni analogues.
(49) Sun, W.-H.; Li, Z.; Hu, H.; Wu, B.; Yang, H.; Zhu, N.; Leng, X.;
Wang, H. New J . Chem. 2002, 26, 1474-1478.
(50) Chan, M. S. W.; Deng, L.; Ziegler, T. Organometallics 2000,
19, 2741-2750.
(51) Fan, L.; Krzywicki, A.; Somogyvari, A.; Ziegler, T. Inorg. Chem.
1994, 33, 5287-5294.
(52) Fan, L.; Krzywicki, A.; Somogyvari, A.; Ziegler, T. Inorg. Chem.
1996, 35, 4003-4006.
(53) Margl, P.; Ziegler, T. J . Am. Chem. Soc. 1996, 118, 7337-7344.
(54) Deng, L.; Margl, P.; Ziegler, T. J . Am. Chem. Soc. 1997, 119,
1094-1100.
(55) Deng, L.; Woo, T. K.; Cavallo, L.; Margl, P. M.; Ziegler, T. J .
Am. Chem. Soc. 1997, 119, 6177-6186.
(56) Woo, T. K.; Bloechl, P. E.; Ziegler, T. J . Phys. Chem. 2000, 104,
121-129.
(57) Musaev, D. G.; Froese, R. D. J .; Morokuma, K. New J . Chem.
1997, 21, 1269-1282.
(58) Musaev, D. G.; Froese, R. D. J .; Svensson, M.; Morokuma, K.
J . Am. Chem. Soc. 1997, 119, 367-374.
(59) Tomita, T.; Takahama, T.; Sugimoto, M.; Sakaki, S. Organo-
metallics 2002, 21, 4138-4146.

3854 Organometallics, Vol. 22, No. 19, 2003
Spencer et al.
Ch a r t 1
4). This suggests that regardless of which site the
ethylene ligand occupies in the cationic Ni complex
[(HNCHCH2NPH3)NiMe(CH2CH2)]+, the M-ethylene
interaction is expected to be weaker than in the diimine
analogue. Furthermore, a lower charge on Ni inhibits
charge transfer from the ethylene C-H bonding orbital
to the empty d orbital, thus also leading to a weaker
agostic interaction between Ni and ethylene. This may
account for the observation of slow dimerization rather
than polymerization of ethylene. F atom substituents
on P in the model HNPF2CHNH resulted in a discern-
ible decrease in lone pair energy and increase in the
charge on Ni, suggesting that the presence of electron-
withdrawing substituents on P could improve the
M-ethylene interactions. Unfortunately, efforts to put
this into practice by the incorporation of C6F5 substit-
uents were unsuccessful, as the corresponding pyri-
dine-phosphine 6 could not be oxidized with aryl azides.
Su m m a r y
We have developed synthetic methods for three
classes of dissymmetric phosphinimine chelate ligands.
Fe and Ni complexes of such ligands, upon activation,
yielded only modest activity for the dimerization of
ethylene. DFT computations infer that inclusion of P
into the ligand results in diminished electrophilicity at
Ni and thus a weakened ethylene-metal interaction.
Efforts to introduce electron-withdrawing groups on the
P atom to explore other applications of these complexes
and to explore the utility of other ligand systems in
ethylene oligomerization are currently underway.
Ta ble 4. DF T Ca lcu la tion s: Liga n d Lon e P a ir
En er giesa a n d Atom ic Ch a r ges on Ni
HNCH- HNPH2- HNCHC- HNPF2C-
CHNH
CHNH
H2NPH3
HNH
E
lone pair(NC)
(HOMO-2)
lone pair(NP)
(HOMO-1)
-11.6;c
-11.3d
-
-11.5
-10.7
-12.5
Ack n ow led gm en t . Financial support from the
NSERC of Canada and NOVA Chemicals Corp. is
gratefully acknowledged. L.P.S. is grateful for the award
of an Ontario Graduate Scholarship, and R.A. is grateful
for support from the Waha Oil Co. D.W.S. is grateful
for the award of Forschungpreis from the Alexander von
Humboldt Stiftung.
E
-9.2
-9.8
-11.2
sym of N[(L)NiMe]+ Cs
C1
C1
C1
[(L)NiMe]+ b
0.858
0.832;e
0.816f
0.809;e
0.830f
0.856;e
0.861f
Energies measured in eV. NBO charge of Ni. c Antibonding
a
b
d
combination of lone pairs. Bonding combination of lone pairs.
e NBO of Ni with CN cis to Ni-Me. f NBO of Ni with PN cis to
Ni-Me.
Su p p or tin g In for m a tion Ava ila ble: Crystallographic
data for all structures reported herein, as CIF files, and figures
giving 1H NMR spectra of all ligands and ligand precursors.
This material is available free of charge via the Internet at
http://pubs.acs.org.
the lone-pair energies for both N-atom donors. This is
also consistent with NBO analysis of the models of
[(L)NiMe]+, which showed that the HNCHCH2NPH3
complex exhibited a lower positive charge on Ni (Table
OM030311T