Anionic phosphinimine-chelate complexes of rhodium and iridium: Steric and electronic influences on oxidative addition of CH2Cl2

Article abstract of DOI:10.1021/om030539g

The phosphinimines Ph₃PNR (R = Ph 1, 2,6-Me₂C₆H₃ 2, 3,5-Me₂C₆H₃ 3, 2,6-i-Pr₂C₆H₃ 4) were prepared and used to generate the species of the form [Li(o-C₆H₄PPh₂NR)]₂· Et₂O (R = Ph 5, 2,6-Me₂C₆H₃ 6, 3,5-Me₂C₆H₃ 7, 2,6-i-Pr₂C₆H₃ 8). Subsequent reactions with [Rh(μ-Cl)-(COD)]₂ gave the complexes Rh(COD)(o-C₆H₄PPh₂NR) (R = Ph 9, 2,6-Me₂C₆H₃ 10, 3,5-Me₂C₆H₃ 11, 2,6-i-Pr₂C₆H₃ 12). Similarly, the Ir analogue of 9 (13) was prepared using [Ir(μ-Cl)(COD)]₂. The reaction of 9 with (CH₂PPh₂)₂ afforded Rh(PPh₂CH₂CH₂PPh₂)(o-C₆ H₄PPh₂NPh) (14). Compound 9 was also shown to react with CH₂Cl₂ to give two products, one of which was confirmed to be [Rh(o-C₆H₄PPh₂NPh)(CH_2-o- C₆H₄PPh₂NPh) (μ-Cl)₂Rh(COD)] (15). Similar treatment of 10 and 12 with CH₂Cl₂ showed no reaction, while reaction of 11 with CH₂Cl₂ gave a mixture of unidentified products. The related imidazole-phosphinimine ligands (N₂C₃H₃)PPh₂NR (R = Ph 18, 2,6-Me₂C₆H₃ 19) were also prepared. These ligands react with NaH to give the corresponding Na-imidazolate-phosphinimines, 20 and 21, and subsequent reaction with [Rh(μ-Cl)(COD)]₂ gave the complexes Rh(COD)((N₂C₃H₂)PPh₂NR) (R = Ph 22, 2,6-Me₂C₆H₃ 23). The compounds 22 and 23 do not react with CH₂Cl₂. The effects of steric and electronic modifications to the ligands on oxidative addition of C-Cl bonds are discussed. DFT calculations were performed on the model fragments [Rh((C₆H₄)PH₂NH)] and [Rh-((N₂C₃H₂)PH₂NH)], and the calculated atomic charges provide some insight into the reactivity of these compounds.

Full text of DOI:10.1021/om030539g

Organometallics 2004, 23, 381-390
381
An ion ic P h osp h in im in e-Ch ela te Com p lexes of Rh od iu m
a n d Ir id iu m : Ster ic a n d Electr on ic In flu en ces on
Oxid a tive Ad d ition of CH2Cl2
Katie T. K. Chan, Liam P. Spencer, J ason D. Masuda, J enny S. J . McCahill,
Pingrong Wei, and Douglas W. Stephan*
Department of Chemistry and Biochemistry, University of Windsor,
Windsor, Ontario, Canada N9B 3P4
Received J uly 16, 2003
The phosphinimines Ph3PNR (R ) Ph 1, 2,6-Me2C6H3 2, 3,5-Me2C6H3 3, 2,6-i-Pr2C6H3 4)
were prepared and used to generate the species of the form [Li(o-C6H4PPh2NR)]2‚Et2O (R )
Ph 5, 2,6-Me2C6H3 6, 3,5-Me2C6H3 7, 2,6-i-Pr2C6H3 8). Subsequent reactions with [Rh(µ-Cl)-
(COD)]2 gave the complexes Rh(COD)(o-C6H4PPh2NR) (R ) Ph 9, 2,6-Me2C6H3 10, 3,5-
Me2C6H3 11, 2,6-i-Pr2C6H3 12). Similarly, the Ir analogue of 9 (13) was prepared using [Ir(µ-
Cl)(COD)]2. The reaction of 9 with (CH2PPh2)2 afforded Rh(PPh2CH2CH2PPh2)(o-C6H4PPh2NPh)
(14). Compound 9 was also shown to react with CH2Cl2 to give two products, one of which
was confirmed to be [Rh(o-C6H4PPh2NPh)(CH2-o-C6H4PPh2NPh)(µ-Cl)2Rh(COD)] (15). Similar
treatment of 10 and 12 with CH2Cl2 showed no reaction, while reaction of 11 with CH2Cl2
gave a mixture of unidentified products. The related imidazole-phosphinimine ligands
(N2C3H3)PPh2NR (R ) Ph 18, 2,6-Me2C6H3 19) were also prepared. These ligands react with
NaH to give the corresponding Na-imidazolate-phosphinimines, 20 and 21, and subsequent
reaction with [Rh(µ-Cl)(COD)]2 gave the complexes Rh(COD)((N2C3H2)PPh2NR) (R ) Ph 22,
2,6-Me2C6H3 23). The compounds 22 and 23 do not react with CH2Cl2. The effects of steric
and electronic modifications to the ligands on oxidative addition of C-Cl bonds are discussed.
DFT calculations were performed on the model fragments [Rh((C6H4)PH2NH)] and [Rh-
((N2C3H2)PH2NH)], and the calculated atomic charges provide some insight into the reactivity
of these compounds.
In tr od u ction
example is (RhCl(dppe)(µ-Cl))2(µ-CH2).10 In rare cases,
oxidative addition of CH2Cl2 is followed by insertion into
the Rh-L bond.7,11 Such is the case in the formation of
(Me3P)3RhCl2(CH2PMe3)12 and RhCl2(CH2P((N(CH2-
CH2N)(CH2CH2)2NH)(PPh3).13
Recently a number of groups have been probing the
utility of diimine (CdNR) and related late metal com-
plexes in olefin polymerization catalysis.14-27 As our
The oxidative addition of alkyl-halides, in particular
alkyl-chlorides, has attracted much academic attention
as a result of the applications of this reaction in
industrial processes. Nonetheless, of the known oxida-
tive reactions of CH2Cl2 to Rh, the majority afford Rh-
(III) products in which RhCl(CH2Cl) fragments are
seen.1-7 As an example, the species Rh(I) precursor [Rh-
(Me2bipy)(DMSO)2]+ was shown to react with CH2Cl2
to give [RhCl(Me2bipy)(DMSO)2(CH2Cl)]+.8 Alterna-
tively, oxidative addition to Rh dimers has led to the
formation of methylene-bridged species.9,10 One such
(10) Ball, G. E.; Cullen, W. R.; Fryzuk, M. D.; J ames, B. R.; Rettig,
S. J . Organometallics 1991, 10, 3767-3769.
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Chem. 1985, 281, 317-347.
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* Correspondingauthor.Fax: 519-973-7098.E-mail: stephan@uwindsor.ca.
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K. J . Chem. Soc., Dalton Trans. 1997, 1075-1081.
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Organometallics 1991, 10, 2706-2708.
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Veldman, N.; Spek, A. L.; van Leeuwen, P. W. N. M.; Vrieze, K.
Organometallics 1997, 16, 887-900.
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21, 2836-2838.
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3219.
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100, 1169-1203.
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A. J . Chem. Soc., Dalton Trans. 1999, 1109-1112.
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10.1021/om030539g CCC: $27.50 © 2004 American Chemical Society
Publication on Web 12/25/2003

382 Organometallics, Vol. 23, No. 3, 2004
Chan et al.
external 85% H3PO4. Combustion analyses were done in-house
employing a Perkin-Elmer CHN analyzer. Ph3PNPh (1) and
[M(µ-Cl)(COD)]2 (M ) Rh, Ir; COD ) cyclooctadiene) were
purchased from the Aldrich Chemical Co. The compounds Li-
(Et2O)C6H4Ph2PNPh (5) and (N2C3H3)PPh2 (17) were gener-
ated with minor modifications to published methods.30-32
group has had success in developing early transition
metal polymerization catalysts based on phosphinimide
ligands,28,29 we have initiated a program examining a
variety of related phosphinimine-based ligands (PdNR)
for late metal chemistry. In a recent work, we described
Syn th esis of P h 3P NR (R ) 2,6-Me2C6H3 (2), 3,5-Me2C6H3
(3), 2,6-i-P r 2C6H3 (4)). Compounds 2-4 were prepared by
similar methods; thus only one representative procedure is
described. A solution of 2,6-Me2C6H3N3 (1.2 g, 9.9 mmol) in
CH2Cl2 (2 mL) was added dropwise at 25 °C to a solution of
PPh3 (1.3 g, 4.9 mmol) in the same solvent (5 mL). The
homogeneous solution was stirred overnight and was then
concentrated to approximately 2 mL in vacuo. Pentane (5 mL)
was added, and a pale yellow solid precipitated out of solution.
The product was filtered, washed with cold pentane (3 × 5
mL), and dried in vacuo. Yield: 1.12 g (64%). 2: 1H NMR δ
7.64-7.71 (m, 6H, PPh3), 7.14-7.16 (m, 2H, Me2C6H3), 7.10-
7.14 (m, 9H, PPh3), 6.86-6.91 (m, 1H, Me2C6H3), 2.24 (s, 6H,
2
Me2C6H3); 13C{1H} NMR δ 148.4 (s), 135.5 (s), 133.6 (d, J P-C
) 78 Hz), 133.2 (s), 133.9 (d, 3J P-C ) 10 Hz), 131.5 (d, 4J P-C
)
the development of phosphinimine-pyridine and phos-
phinimine-imidazole chelate complexes of Fe and Ni.30
While these complexes provided only modestly active
ethylene oligomerization calatysts, the insight garnered
from DFT computations infers that inclusion of the P-N
fragment into the ligand results in increased nucleo-
philicity of the metal center. While this characteristic
weakens ethylene-metal interactions, it should in
principle enhance oxidative addition reactions. In this
paper, we describe the preparation of Rh and Ir com-
plexes of ortho-metalated phenyl-phosphinimine and
imidazolate-phosphinimine ligands. In some cases, these
species undergo oxidative addition of CH2Cl2, resulting
in C-C bond formation via insertion into the Rh-aryl-C
bond. However, steric congestion or electronic perturba-
tions to the ligand are shown to inhibit this reaction.
These experimental results are considered and dis-
cussed in the light of DFT calculations.
4
3 Hz), 128.1-128.8 (m, obscured by C6D6), 119.5 (d, J P-C ) 3
Hz), 21.8 (s); 31P{1H} NMR δ -9.8 (s). Anal. Calcd for C26H24
-
PN: C, 81.87; H, 6.34; N, 3.67. Found: C, 81.46; H, 6.41; N,
3.49. 3: Yield 1.02 g (70%); 1H NMR δ 7.80-7.87 (m, 6H,
PPh3), 6.93-7.06 (m, 9H, PPh3), 6.93 (s, 2H, Me2C6H3), 6.48
(s, 1H, Me2C6H3), 2.19 (s, 6H, Me2C6H3); 13C{1H} NMR δ 152.2
2
2
(s), 138.2 (s), 133.3 (d, J P-C ) 10 Hz), 133.1 (d, J P-C ) 98
4
Hz), 131.7 (d, J P-C ) 2 Hz), 128.1-129.0 (m, obscured by
C6D6), 122.2 (d, 3J P-C ) 18 Hz), 120.2 (s), 21.3 (s); 31P{1H} NMR
δ -1.5 (s). Anal. Calcd for C26H24PN: C, 81.87; H, 6.34; N,
3.67. Found: C, 81.53; H, 6.19; N, 3.39. 4: Yield 1.34 g (80%);
1H NMR δ 7.61-7.69 (m, 6H, PPh3), 7.14-7.22 (m, 3H,
3
i-Pr2C6H3), 6.95-7.08 (m, 9H, PPh3), 3.67 (sept, 2H, J H-H
)
7 Hz, i-Pr), 1.09 (d, 12H, J H-H ) 7 Hz, i-Pr); 13C{1H} NMR δ
3
1
2
145.1 (s), 143.3 (d, J P-C ) 7 Hz), 134.3 (d, J P-C ) 101 Hz),
3
4
133.0 (d, J P-C ) 9 Hz), 131.7 (d, J P-C ) 2 Hz), 128.2-128.9
4
(m, obscured by C6D6), 123.6 (s), 120.4 (d, J P-C ) 3 Hz), 29.4
(s), 24.3 (s); 31P{1H} NMR δ -8.9 (s). Anal. Calcd for C30H32
-
PN: C, 82.35; H, 7.37; N, 3.20. Found: C, 82.46; H, 7.42; N,
3.19.
Gen er a tion of [Li(o-C6H4P h 2P NR)]2(Et2O) (R ) P h (5),
2,6-Me2C6H3 (6), 3,5-Me2C6H3 (7), 2,6-i-P r 2C6H3 (8)). These
compounds were prepared in a similar fashion although the
Li reagent and time of reactions varied. One preparation is
detailed, and variations for the others are indicated. Com-
pound 2 (0.2 g, 0.52 mmol) was dissolved in Et2O (5 mL), and
LiMe (0.45 mL, 0.63 mmol) was added dropwise at 25 °C. The
solution turned yellow immediately and gradually changed
color to light orange. The mixture was stirred overnight, after
Exp er im en ta l Section
Gen er a l Da ta . All preparations were done under an
atmosphere of dry, O2-free N2 employing both Schlenk line
techniques and either a Vacuum Atmospheres or Innovative
Technolgies inert atmosphere glovebox. Solvents were purified
employing a Grubbs type solvent purification system manu-
factured by Innovative Technology. All organic reagents were
purified by conventional methods. 1H, 31P{1H}, and 13C{1H}
NMR spectra were recorded on Bruker Avance-300 and -500
spectrometers. All spectra were recorded in C6D6 at 25 °C
unless otherwise noted. Trace amounts of protonated solvents
were used as references, and chemical shifts are reported
relative to SiMe4. 31P{1H} NMR spectra were referenced to
which time the solvent was removed in vacuo. 5: LiPh,
3
overnight, yield 0.16 g (47%); 1H NMR δ 8.28 (d, 1H, J H-H
)
7 Hz, PC6H4), 7.89 (m, 4H, PPh2), 7.28 (m, 2H, NPh), 7.09-
6.95 (m, 7H), 6.89-6.94 (m, 4H, PPh2), 6.61 (m, 1H, PC6H4),
3.35-3.31 (m, 2H, CH2), 1.15 (m, 3H, CH2Me); 13C{1H} NMR
2
δ 151.7 (s), 142.1 (s), 133.4 (d, J P-C ) 9 Hz), 132.5 (s), 131.5
(23) Coles, M. P.; Dalby, C. I.; Gibson, V. C.; Clegg, W.; Elsegood,
M. R. J . Chem. Commun. 1995, 1709-1711.
(s), 130.8 (s), 129.5-129.8 (m), 128.5-128.8 (m), 123.9-124.5
7
(m), 123.3 (s), 117.9 (s), 65.6 (s), 14.9 (s); Li{1H} NMR δ 4.2
(24) 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.
1
(s); 31P{1H} NMR δ 18.1 (s). 6: Yield 0.18 g (85%); H NMR δ
8.51 (br, 1H, PC6H4), 7.51-7.54 (m, 4H, PPh2), 7.28 (br, 1H,
Me2C6H3), 7.00-7.04 (m, 4H, PPh2), 6.93-6.96 (m, 6H), 6.79-
6.81 (m, 1H, PC6H4), 3.08-3.12 (m, 2H, CH2), 1.96 (s, 6H,
Me2C6H3), 0.85-0.90 (m, 3H, CH2Me); 13C{1H} NMR δ 147.8
(s), 141.9 (s), 141.2 (s), 134.5 (d, 1J P-C ) 7 Hz), 133.2 (s), 132.7
(d, 2J P-C ) 8 Hz), 131.6 (s), 130.2 (s), 128.7 (s), 123.4 (s), 120.5
(s), 65.1 (s), 20.7 (s), 14.5 (s); 7Li{1H} NMR δ 3.38 (s); 31P{1H}
NMR δ 15.2 (s). 7: BuLi, overnight, yield 0.13 g (63%); 1H
NMR δ 8.28 (br, 1H, PC6H4), 7.75-7.85 (m, 4H, PPh2), 7.26-
(25) Britovsek, G. J . P.; Gibson, V. C.; Wass, D. F. Angew. Chem.,
Int. Ed. 1999, 38, 428-447.
(26) Gibson, V. C.; Newton, C.; Redshaw, C.; Solan, G. A.; White,
A. J . P.; Williams, D. J . J . Chem. Soc., Dalton Trans. 1999, 827-829.
(27) 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.
(28) Stephan, D. W.; Guerin, F.; Spence, R. E. v. H.; Koch, L.; Gao,
X.; Brown, S. J .; Swabey, J . W.; Wang, Q.; Xu, W.; Zoricak, P.; Harrison,
D. G. Organometallics 1999, 18, 2046-2048.
(29) Stephan, D. W.; Stewart, J . C.; Guerin, F.; Spence, R. E. v. H.;
Xu, W.; Harrison, D. G. Organometallics 1999, 18, 1116-1118.
(30) Spencer, L. P.; Altwier, R.; Wei, P.; Gelmini, L.; Gauld, J .;
Stephan, D. W. Organometallics 2003, 22, 3841.
(31) Stuckwisch, C. G. J . Org. Chem. 1976, 41, 1173-1176.
(32) Curtis, N. J .; Brown, R. S. J . Org. Chem. 1980, 45, 4038-4040.

Anionic Phosphinimine-Chelate Rh and Ir Complexes
Organometallics, Vol. 23, No. 3, 2004 383
7.32 (m, 1H, PC6H4), 7.18 (m, 1H, PC6H4), 6.93-7.08 (m, 8H),
6.35-6.36 (m, 2H, Me2C6H3), 2.82 (br, 2H, CH2), 1.97-2.10
(m, 6H, Me2C6H3), 0.49 (br, 3H, CH2Me); 13C{1H} NMR δ 151.7
(s); 31P{1H} NMR δ 39.9. Anal. Calcd for C38H43PNRh: C,
70.47; H, 6.69; N, 2.16. Found: C, 70.34; H, 6.54; N, 2.01. 13:
3
Yield 0.06 g (67%); 1H NMR δ 7.85 (d, 1H, J P-H ) 9 Hz,
2
(s), 144.9 (s), 142.2 (s), 138.6 (s), 137.8 (s), 134.1 (d, J P-C ) 9
PC6H4), 7.53-7.60 (m, 4H, PPh2), 7.25-7.30 (m, 1H, PC6H4),
7.07-7.11 (m, 2H, NPh), 6.90-6.98 (m, 6H), 6.81-6.87 (m, 4H,
PPh2), 6.73-6.78 (m, 1H, PC6H4), 3.82-3.99 (m, 4H, COD),
2.35-2.61 (m, 4H, COD), 1.82-1.99 (m, 4H, COD); 13C{1H}
Hz), 133.3 (s), 132.8 (s), 131.4 (s), 131.2 (s), 130.4 (s), 122.9
(s), 65.9 (s), 21.9 (s), 14.7 (s); 7Li{1H} NMR δ: 4.21 (s); 31P-
{1H} NMR δ 17.9 (s). 8: LiMe, 12 days at 25 °C; yield 0.14 g
2
1
3
NMR δ 172.9 (s), 146.3 (s), 140.9 (s), 135.5 (s), 133.2 (d, J P-C
(52%); H NMR δ 8.61 (d, 1H, J H-H ) 7 Hz, PC6H4), 7.48-
7.51 (m, 4H, PPh2), 7.23-7.25 (m, 2H, i-Pr2C6H3), 6.89-7.10
(m, 10H, PPh2), 3.65 (sept, 2H, 3J H-H ) 7 Hz, i-Pr), 3.21-3.27
(m, 2H, CH2), 1.22 (br, 6H, i-Pr), 1.06-1.10 (m, 3H, CH2Me),
) 9 Hz), 133.1 (s), 130.4 (s), 130.1 (s), 129.8 (s), 129.5 (s), 124.3
(s), 123.9 (s), 77.8 (s), 52.7 (s), 33.3 (s), 31.4 (s); 31P{1H} NMR
δ 57.7 (s). Anal. Calcd for C32H31PNIr: C, 58.88; H, 4.79; N,
2.15. Found: C, 58.69; H, 4.77; N, 2.05.
1
0.57 (br, 6H, i-Pr); 13C{1H} NMR δ 145.2 (d, J P-C ) 7 Hz),
1
2
144.6 (s), 142.7 (d, J P-C ) 7 Hz), 134.4 (s), 133.1 (d, J P-C
)
Syn th esis of Rh (P P h 2CH2CH2P P h 2)(o-C6H4P P h 2NP h )
(14). To a solution of 9 (0.03 g, 0.08 mmol) in THF (5 mL) was
added dropwise a solution of 1,2-bis(diphenylphosphinoethane)
(0.04 g, 0.07 mmol) in THF (5 mL). The mixture was stirred
overnight at 25 °C, and the solvent was then removed in vacuo.
The resulting solid was washed with benzene and was
8 Hz), 132.4 (d, 2J P-C ) 9 Hz), 130.9 (s, PPh2), 130.6 (s), 124.3
(s), 123.5 (s), 122.3 (s), 119.9 (s), 65.7 (s), 28.9 (s), 23.8 (s), 15.3
(s); Li{1H} NMR δ 6.73 (s); 31P{1H} NMR δ 18.4 (s).
7
Syn th esis of Rh (COD)(o-C6H4P P h 2NR), R ) P h (9), 2,6-
Me2C6H3 (10), 3,5-Me2C6H3 (11), 2,6-i-P r 2C6H3 (12), a n d Ir -
(COD)(o-C6H4P P h 2NP h ) (13). Compounds 9-13 were pre-
pared by similar methods; thus only one representative
procedure is described. A mixture of 6 (0.26 g, 0.31 mmol) and
[Rh(µ-Cl)(COD)]2 (0.22 g, 0.44 mmol) was dissolved in THF (5
mL) at 25 °C. The homogeneous reddish solution was stirred
overnight, after which the solvent was removed in vacuo. The
residue was washed with pentane and recrystallized from
THF/Et2O or THF/C6H6. 9: Yield 0.24 g (60%); 1H NMR δ
7.61-7.67 (m, 4H, PPh2), 7.53-7.55 (m, 1H, PC6H4), 7.18-
7.24 (m, 1H, PC6H4), 6.98-7.06 (m, 4H, PPh2), 6.95-6.96 (m,
2H, NPh), 6.84-6.92 (m, 6H), 6.74-6.79 (m, 1H, PC6H4), 4.36-
4.39 (m, 2H, COD), 4.13-4.16 (m, 2H, COD), 2.50-2.60 (m,
1
subsequently dried in vacuo. Yield: 0.03 g (51%); H NMR δ
7.99-8.03 (m, 4H, PPh2), 7.74 (br, 1H, PC6H4), 7.53-7.57 (m,
4H, PPh2), 7.48-7.51 (m, 4H, PPh2), 7.02-7.08 (m, 15H), 6.93-
3
6.99 (m, 6H), 6.81 (t, 1H, J H-H ) 7 Hz, PC6H4), 6.70 (dd, 1H,
3J P-H ) 13 Hz, 3J H-H ) 6 Hz, PC6H4), 6.53-6.56 (m, 2H, NPh),
6.45-6.48 (m, 1H, PC6H4), 1.83-1.93 (m, 2H, CH2), 1.64-1.73
(m, 2H, CH2); 13C{1H} NMR δ 153.9 (s), 146.3 (s), 144.6 (s),
2
2
142.2 (br), 138.6 (d, J P-C ) 24 Hz), 137.9 (d, J P-C ) 23 Hz),
1
2
134.4 (d, J P-C ) 33 Hz), 133.6 (d, J P-C ) 11 Hz), 132.5 (s),
2
131.4 (s), 130.9 (s), 128.7 (s), 126.2 (d, J P-C ) 13 Hz), 123.5
(s), 121.1 (d, 2J P-C ) 15 Hz), 119.2 (s), 32.1 (br), 29.4 (br); 31P-
{1H} NMR δ 74.9 (dd, J Rh-P ) 104 Hz, J P-P ) 24 Hz), 57.2
1
2
(ddd J Rh-P ) 121 Hz, 2J P-P ) 25 Hz, 3J P-P ) 11 Hz), 24.1 (dd,
1
2H, COD), 2.36-2.46 (m, 2H, COD), 2.02-2.11 (m, 2H, COD),
2J Rh-P ) 24 Hz, J P-P ) 11 Hz). Anal. Calcd for C50H43P3NRh:
3
1
1.91-1.98 (m, 2H, COD); 13C{1H} NMR δ 174.0 (d, J Rh-C
)
2
2
C, 70.34; H, 5.08; N, 1.64. Found: C, 69.95; H, 5.38; N, 1.55.
Syn th esis of[Rh (o-C6H4P P h 2NP h )(CH2-o-C6H4P P h 2NP h )-
(µ-Cl)2Rh (COD)] (15). Compound 9 (0.098 g, 0.17 mmol) was
dissolved in CH2Cl2 (10 mL) and heated at reflux for 24 h,
during which time the solution became orange. The solvent
was removed in vacuo, and the product was recrystallized in
benzene/CH2Cl2 following filtration. Yield: 0.18 g (94%); 1H
40 Hz), 148.1 (d, J P-C ) 4 Hz), 140.1 (s), 133.1 (d, J P-C ) 9
Hz), 131.6 (s), 129.9 (s), 129.7 (s), 129.4 (s), 129.3 (s), 128.5
1
1
(s), 123.4 (s), 122.9 (s), 93.4 (d, J Rh-C ) 7 Hz), 68.9 (d, J Rh-C
2
) 15 Hz), 32.5 (s), 30.7 (s); 31P{1H} NMR δ 46.4 (d, J Rh-P
)
10 Hz). Anal. Calcd for C32H31PNRh: C, 68.21; H, 5.55; N, 2.49.
Found: C, 68.27; H, 5.71; N, 2.67. 10: Yield 0.08 g (43%); H
NMR δ 7.56-7.60 (m, 4H, PC6H4), 7.25 (d, 1H, J H-H ) 7 Hz,
1
3
3
NMR δ 8.40 (br, 2H, P(C6H4)), 7.97 (dd, 1H, J Rh-H ) 8 Hz,
PC6H4), 6.82-6.96 (m, 11H), 4.17-4.18 (m, 2H, COD), 3.94-
3.95 (m, 2H, COD), 2.54-2.56 (m, 2H, COD), 2.36-2.38 (m,
2H, COD), 2.12 (s, 6H, Me2C6H3), 2.04-2.07 (m, 2H, COD),
4J P-H ) 3 Hz, P(C6H4)), 7.87-7.92 (m, 4H, PPh2), 7.79-7.84
(m, 2H, P(C6H4)), 7.65-7.69 (m, 3H, P(C6H4)), 7.45-7.53 (m,
3
1
1.91-1.94 (m, 2H, COD); 13C{1H} NMR δ 173.5 (d, J Rh-C
)
4H, PPh2), 7.28 (t, 2H, J H-H ) 7 Hz, NPh), 6.83-7.13 (m,
2
2
16H), 6.68-6.76 (m, 4H, NPh), 4.23 (dd, 2H, J Rh-H ) 10 Hz,
41 Hz), 145.4 (s), 136.5 (s), 135.5 (s), 132.8 (d, J P-C ) 9 Hz),
131.1 (s), 130.9 (s), 129.9 (s), 129.8 (s), 129.6 (s), 128.2 (s) 123.9
4J P-H ) 4 Hz, RhCH2), 4.10-4.12 (m, 2H, COD), 3.78-3.80
(m, 2H, COD), 2.21-2.26 (m, 4H, COD), 1.33-1.37 (m, 4H,
COD); 13C{1H} NMR δ 170.7 (m), 157.9 (s), 150.9 (s), 148.9
(s), 138.1 (s), 134.8-137.9 (m), 134.7 (s), 134.1 (s), 132.9-133.1
(m), 132.7 (s), 131.5-131.6 (m), 130.8 (s), 130.5 (s), 125.0 (s),
1
1
(br), 94.4 (d, J Rh-C ) 7 Hz), 68.8 (d, J Rh-C ) 15 Hz), 32.3 (s),
30.0 (s), 20.9 (s); 31P{1H} NMR δ 43.3 (d, 2J Rh-P ) 11 Hz). Anal.
Calcd for C34H35PNRh: C, 69.04; H, 5.96; N, 2.37. Found: C,
68.61; H, 5.70; N, 2.28. 11: 1H NMR δ 7.65-7.69 (m, 4H,
1
3
3
124.6 (s), 122.9 (s), 122.1 (s), 121.6 (s), 78.3 (d, J Rh-C ) 14
PPh2), 7.55 (d, 1H, J H-H ) 7 Hz, C6H4), 7.23 (d, 1H, J H-H
)
1
3
3
Hz), 76.3 (dd, J Rh-C ) 32 Hz, J P-C ) 14 Hz), 31.3 (s), 30.9
7 Hz, C6H4), 7.04 (d, 1H, J H-H ) 7 Hz, C6H4), 6.98-7.00 (m,
2H, PPh2), 6.88-6.93 (m, 5H), 6.65 (s, 2H, C6H3), 6.47 (s, 1H,
C6H3), 4.46-4.48 (m, 2H, COD), 4.14-4.16 (m, 2H, COD),
2.55-5.58 (m, 2H, COD), 2.42-2.44 (m, 2H, COD), 2.06-2.08
(m, 2H, COD), 2.00-2.02 (m, 2H, COD), 1.97 (s, 6H, Me); 13C-
(s); 31P{1H} NMR δ 43.8 (d, J Rh-P ) 12 Hz), 27.1 (d, J Rh-P
)
2
2
3 Hz). Anal. Calcd for C57H52P2N2Cl2Rh2: C, 62.03; H, 4.75;
N, 2.54. Found: C, 61.89; H, 4.55; N, 2.38.
Syn t h esis of (N2C3H 3)P P h 2NR , R ) P h (18), 2,6-
Me2C6H3 (19). These compounds were prepared by similar
methods employing the precursor 17; thus only one represen-
tative procedure is described employing the precursor phos-
phine 17. To a stirred THF (20 mL) solution of 17 (1.01 g, 4.0
mmol) was added a THF solution of 2,6-Me2C6H3N3 (1.2 g, 8.0
mmol) over 30 min at 25 °C. Gas evolution was observed. The
yellow solution was then stirred overnight, and the solvent
removed in vacuo. The residue was dissolved in 3-5 mL of
THF, and petroleum ether (bp 30-60 °C) was added slowly to
precipitate a creamy white solid. The solid was filtered and
washed with petroleum ether several times to give a white
solid 19. 18: Yield 92%; 1H NMR (CDCl3) δ 7.81-7.93 (m, 4H,
{1H} NMR δ 174.2 (d, J Rh-C ) 40 Hz), 147.9 (s), 141.9 (s),
1
2
1
137.5 (s), 135.4 (d, J P-C ) 18 Hz), 133.5 (d, J P-C ) 9 Hz),
131.7 (s), 130.3 (s), 130.0 (s), 128.6 (s), 128.4 (s), 127.4 (d, 3J Rh-C
1
) 7 Hz), 125.1 (s), 123.4 (s), 93.8 (d, J Rh-C ) 7 Hz), 69.1 (d,
1J Rh-C ) 15 Hz), 32.6 (s), 30.1 (s), 21.4 (s); 31P{1H} NMR δ
47.6 (s). Anal. Calcd for C34H35PNRh: C, 69.04; H, 5.96; N, 2.37.
Found: C, 69.00; H, 5.59; N, 2.24. 12: Yield 0.08 g (43%); H
NMR δ 7.74-7.78 (m, 4H, PPh2), 7.51 (d, 1H, J Rh-H ) 8 Hz,
1
3
PC6H4), 7.19 (s, 1H, PC6H4), 6.99-7.02 (m, 4H, PPh2), 6.93-
6.97 (m, 2H, i-Pr2C6H3), 6.86-6.92 (m, 5H), 4.18-4.21 (m, 4H,
COD), 2.41-2.54 (m, 4H, COD), 1.96-2.01 (m, 4H, COD), 1.52
3
3
(d, 6H, J H-H ) 7 Hz, i-Pr), 0.40 (d, 6H, J H-H ) 7 Hz, i-Pr);
13C{1H} NMR δ 173.6 (d, J Rh-C ) 40 Hz), 146.5 (d, J P-C ) 6
Hz), 143.0 (d, J P-C ) 5 Hz), 140.3 (s), 135.5 (d, J Rh-C ) 18
Hz), 132.7 (d, 2J P-C ) 8 Hz), 131.4 (s), 131.3 (s), 130.3 (s), 129.6
(s), 129.4 (s), 124.1 (s), 123.8 (d, 3J P-C ) 3 Hz), 123.3 (s), 123.1
PPh2), 7.39-7.55 (m, 6H, PPh2), 7.23 (d, J H-H ) 2 Hz, 2H,
1
1
3
1
2
3
N2C3H3), 6.93-7.02 (m, 2H, NC6H5), 6.83 (d, J H-H ) 8 Hz,
3
2H, NC6H5), 6.69 (t, J H-H ) 7 Hz, 1H, NC6H5); 13C{1H} NMR
(THF) (partial) δ 151.4 (s), 139.8 (d, 1J P-C ) 142 Hz), 132.4 (d,

384 Organometallics, Vol. 23, No. 3, 2004
Chan et al.
3J P-C ) 10 Hz), 132.9 (s), 130.5 (d, J P-C ) 132 Hz), 129.4 (s),
2J P-C ) 9 Hz), 131.4 (s), 131.1 (s), 128.3 (s), 128.2 (d, J P-C
)
3
3
3
3
3
11 Hz), 125.8 (br), 123.4 (d, J P-C ) 19 Hz), 116.9 (s); 31P{1H}
NMR (THF) δ -12.2 (s). Anal. Calcd for C21H18PN3: C, 73.46;
H, 5.28; N, 12.24. Found: C, 73.34; H, 5.23; N, 12.45. 19: Yield
95%; 1H NMR (d8-THF) δ 7.83-7.91 (m, 4H, PPh2), 7.34-7.46
129.2 (d, J P-C ) 12 Hz), 126.7 (d, J P-C ) 10 Hz), 124.5 (s),
2 2
83.7 (d, J Rh-C ) 12 Hz), 74.5 (d, J Rh-C ) 14 Hz), 31.7 (s),
31.5 (s), 14.5 (s); 31P{1H} NMR (d8-THF) δ 17.9 (s). Anal. Calcd
for C31H33N3PRh: C, 64.03; H, 5.72; N, 7.23. Found: C, 64.43;
H, 5.61; N, 7.20.
3
(m, 6H, PPh2), 7.25-7.26 (m, 2H, N2C3H3), 6.78 (d, J H-H ) 7
Hz, 2H, Me2C6H3), 6.42-6.54 (m, 1H, N2C3H3), 1.97 (s, 6H,
Com p u ta tion s. All calculations were performed using the
Gaussian 98 suite of programs.33 The structures were opti-
mized with Cs symmetry constraints. Calculations were per-
formed at the DFT level using the hybrid B3LYP method.34,35
The 6-31G(d) basis set was used on C, H, N, and P. For Ni,
the LANL2DZ basis set with corresponding effective core
potentials was applied.36 Natural population analysis37,38 was
performed using the NBO program as implemented by Gauss-
ian 98.
X-r a y Da ta Collection a n d Red u ction . 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 in a
hemisphere of data in 1329 frames with 10 s exposure times.
The observed extinctions were consistent with the space groups
in each case. The data sets were collected (4.5° < 2θ < 45-
50.0°). A measure of decay was obtained by re-collecting the
first 50 frames of each data set. The intensities of reflections
within these frames showed no statistically significant change
over the duration of the data collections. The data were
processed using the SAINT and XPREP processing packages.
An empirical absorption correction based on redundant data
was applied to each data set. Subsequent solution and refine-
ment was performed using the SHELXTL solution package
operating on a Pentium computer.
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.39 The heavy atom positions were determined using
direct methods employing the SHELXTL direct methods
routine. The remaining non-hydrogen atoms were located from
successive difference Fourier map calculations. The refine-
ments 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. In the
final cycles of each refinement, all non-hydrogen atoms were
assigned anisotropic temperature factors in the absence of
disorder or insufficient data. In the latter cases atoms were
treated isotropically. C-H 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. H atom temperature
factors were fixed at 1.10 times the isotropic temperature
factor of the C atom to which they are bonded. The H atom
contributions were calculated, but not refined. The locations
of the largest peaks in the final difference Fourier map
Me); 13C{1H} NMR (d8-THF) δ 144.9, 140.0 (d, J P-C ) 155
1
3
3
Hz), 132.0 (d, J P-C ) 89 Hz), 130.0 (d, J P-C ) 8 Hz), 129.9
3
3
(d, J P-C ) 10 Hz), 129.1, 126.0 (d, J P-C ) 13 Hz), 125.8 (d,
3J P-C ) 3 Hz), 125.6, 122.8, 116.2, 18.5; 31P{1H} NMR (d8-THF)
δ -21.4 (s). Anal. Calcd for C23H22PN3: C, 74.38; H, 5.97; N,
11.31. Found: C, 74.24; H, 6.09; N, 11.29.
Gen er a tion of [Na (THF )((N2C3H2)P P h 2NR)]n , R ) P h
(20), 2,6-Me2C6H3 (21). These compounds were prepared by
similar methods; thus only one representative procedure is
described. To a stirred suspension of NaH (24 mg, 0.96 mmol)
in THF (10 mL) was added dropwise a THF solution (10 mL)
of 19 (300 mg, 0.810 mmol). Gas evolution occurred im-
mediately, and the suspension was stirred overnight. The
solution was filtered through Celite and the solvent removed
in vacuo to give a white solid. This was recrystallized with
1
THF/pentane to give colorless crystals of 20. Yield: 77%; H
NMR (d8-THF) δ 7.91-7.97 (m, 4H, PPh2), 7.25-7.36 (m, 6H,
PPh2), 7.11-7.16 (m, 2H, N2C3H2), 6.80-6.85 (m, 2H, NC6H5),
3
3
6.71 (d, J H-H ) 8 Hz, 2H, NC6H5), 6.44 (t, J H-H ) 7 Hz, 1H,
NC6H5), 3.59-3.64 (m, 4H, THF), 1.74-1.80 (m, 4H, THF);
13C{H} NMR (d8-THF) δ 154.2 (s), 143.7 (d, J P-C ) 185 Hz),
1
3
3
135.6 (d, J P-C ) 90 Hz), 134.0 (d, J P-C ) 9 Hz), 133.15 (d,
3J P-C ) 9.2 Hz), 131.5 (d, J P-C ) 16.2 Hz), 132.3 (s), 129.4
3
(s), 128.4 (d, 3J P-C ) 11.2 Hz), 124.4 (d, 3J P-C ) 17.7 Hz), 117.3
(s), 68.4 (s), 26.6 (s); 31P{1H} NMR (d8-THF) δ 1.04 (s). 21:
Yield 85%; 1H NMR (d8-THF) δ 7.56-7.68 (m, 4H, PPh2), 7.24-
7.26 (m, 2H, N2C3H2), 7.15-7.20 (m, 6H, PPh2), 6.74 (d, 3J H-H
) 7.5 Hz, 2H, Me2C6H3), 6.45-6.51 (m, 1H, Me2C6H3), 3.60-
3.61 (m, 4H, THF), 1.93 (s, 6H, Me), 1.75-1.80 (m, 4H, THF);
13C{H} NMR (d8-THF) δ 150.5 (s), 144.5 (d, J P-C ) 187 Hz),
1
3
3
138.0 (d, J P-C ) 90 Hz), 134.4 (d, J P-C ) 7.4 Hz), 133.1 (d,
3J P-C ) 9 Hz), 131.1 (d, J P-C ) 17 Hz), 130.6 (s), 128.3 (d,
3
3J P-C ) 2 Hz), 128.1 (d, J P-C ) 11 Hz), 119.4 (d, J P-C ) 3
Hz), 117.3 (s), 68.4 (s), 26.6 (s), 21.4 (s); 31P{1H} NMR (d8-
THF) δ -4.7 (s).
3
3
Syn th esis of Rh (COD)((N2C3H2)P P h 2NR), R ) P h (22),
2,6-Me2C6H3 (23). These compounds were prepared by similar
methods; thus only one representative procedure is described.
To a stirred benzene (10 mL) solution of [Rh(µ-Cl)(COD)]2 (67
mg, 0.14 mmol) was added a benzene (5 mL) suspension of 21
(126 mg, 0.28 mmol). The suspension was stirred overnight
and filtered through Celite, and the solvent was removed.
Recrystallization with benzene/pentane gave a yellow solid.
Suitable X-ray quality crystals were grown by slow diffusion
of pentane into a concentrated CH2Cl2 solution of the com-
pound. 22: Yield 87%; 1H NMR (d8-THF) δ 7.65-7.70 (m, 4H,
PPh2), 7.50-7.53 (m, 2H, PPh2), 7.37-7.43 (m, 4H, PPh2), 7.16
(33) 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.
3
(d, J H-H ) 3 Hz, 1H, N2C3H2), 6.98-7.14 (m 2H, NC6H5),
6.86-6.92 (m, 1H, NC6H5), 6.75-6.80 (m, 3H, NC6H5 and
N2C3H2), 4.21-4.24 (m, 2H, COD), 3.51-3.53 (m, 2H, COD),
2.27-2.47 (m, 4H, COD), 1.82-1.87 (m, 2H, COD), 1.73-1.76
(m, 2H, COD); 13C{1H} NMR (d8-THF) (partial) δ 146.1 (s),
1
2
144.6 (d, J P-C ) 193 Hz), 132.9 (d, J P-C ) 10 Hz), 132.7 (d,
3J P-C ) 15 Hz), 131.9 (s), 129.6 (d, J P-C ) 6 Hz), 128.1 (d,
3
3J P-C ) 11 Hz), 128.0 (s), 125.5 (d, J P-C ) 10 Hz), 123.2 (s),
3
2
2
81.8 (d, J Rh-C ) 12 Hz), 73.2 (d, J Rh-C ) 13 Hz), 30.6 (s),
30.2 (s); 31P{1H} NMR (d8-THF) δ 24.3 (s). Anal. Calcd for
C
29H29N3PRh: C, 62.94; H, 5.28; N, 7.59. Found: C, 61.10; H,
(34) Becke, A. D. Phys. Rev. A 1998, 38, 3098.
1
5.37; N, 7.10. 23: Yield 95%; H NMR (d8-THF) δ 7.66-7.73
(m, 4H, PPh2), 6.82-7.13 (m, 11H, N2C3H2), 4.37-4.39 (m, 2H,
COD), 3.25-3.27 (m, 2H, COD), 2.17-2.39 (m, 4H, COD), 2.02
(s, 6H, Me), 1.62-1.74 (m, 2H, COD), 1.51-1.63 (m, 2H, COD);
(35) Lee, C.; Yang, W.; Parr, R. G. Phys. Rev. B 1980, 37, 785.
(36) Hay, P. J .; Wadt, W. R. J . Chem. Phys. 1985, 82, 270-283.
(37) Reed, A. E.; Weinstock, R. B.; Weinhold, F. J . Chem. Phys. 1985,
83, 735-746.
(38) Reed, A. E.; Weinhold, F. J . Chem. Phys. 1983, 78, 4066-4073.
(39) Cromer, D. T.; Mann, J . B. Acta Crystallogr. A 1968, A24, 321-
324.
13C{H} NMR (d8-THF) δ 145.0 (d, J P-C ) 196 Hz), 144.7 (s),
1
3
3
137.5 (d, J P-C ) 5 Hz), 134.1 (d, J P-C ) 17 Hz), 133.4 (d,

Anionic Phosphinimine-Chelate Rh and Ir Complexes
Organometallics, Vol. 23, No. 3, 2004 385
Sch em e 1
F igu r e 1. ORTEP drawing of 2 with 30% thermal el-
lipsoids; hydrogen atoms have been omitted for clarity.
Selected bond distances and angles: P-N 1.553(2) Å, N-C
1.403(3) Å, P-N-C 132.31(16)°.
calculation as well as the magnitude of the residual electron
densities in each case were of no chemical significance.
Addition details are provided in the Supporting Information.
spectra of these species showed resonances in the range
of 170-180 ppm with J Rh-C of ca. 40 Hz, consistent
1
with metalation at the ortho-aryl carbon. 1H NMR
spectra also showed resonances attributed to two sets
of distinct methylene and methine protons of the COD
ligand, consistent with the dissymmetry of the meta-
lated phosphinimine ligand. The upfield methylene and
methine signals were assigned to those trans to the aryl-
carbon. This was unambiguously confirmed by a NOE-
SY NMR experiment in the case of 9. Crystals of 9-12
suitable for X-ray structural determination were ob-
tained via recrystallization.
Resu lts a n d Discu ssion
While the phosphinimine Ph3PNPh is commercially
available, the analogues Ph3PNR (R ) 2,6-Me2C6H3 2,
3,5-Me2C6H3 3, 2,6-i-Pr2C6H3 4) were synthesized in
high yields by oxidation of PPh3 with the appropriate
aryl azide. NMR data were consistent with these formu-
lations and confirmed crystallographically in the case
of 2 (Figure 1). The structure is unexceptional with a
P-N bond distance of 1.553(2) Å, typical of phosphini-
mines.40-42 Subsequent lithiation of these species was
performed employing methods similar to those described
in the literature for the lithiation of Ph3PNPh,31 al-
though the Li reagent and the duration of the reaction
were varied with each case. In this way the species of
[Li(o-C6H4PPh2NPh)]2‚Et2O (R ) Ph 5, 2,6-Me2C6H3 6,
3,5-Me2C6H3 7, 2,6-i-Pr2C6H3 8) were obtained in yields
ranging from 47 to 85%. NMR data were consistent with
lithiation at the ortho position of one of the P-bound
phenyl rings. The nature of these salts in the solid state
is unknown, although it is noteworthy that Steiner et
al. have structurally characterized the related Li salt
[Li(o-C6H4PPh2NSiMe3)]2‚Et2O.43 Our analogous dimer-
ic formulation is based on NMR and EA data.
The solid state structures for 9-12 were similar
(Figure 2). All confirmed the expected pseudo-square-
planar coordination sphere about Rh comprised of the
σ-bonded aryl carbon, the phosphinimine N donor, and
the coordinated COD molecule. The Rh-C and Rh-N
distances are similar in these compounds, with the
Rh-N distances ranging from 2.105(3)-2.140(2) Å,
while the Rh-C distances fall within 2.057(3)-2.071(3)
Å, which are only slightly shorter than the Rh-C
distance (2.090(1) Å) seen in the Rh(I) species RhPh-
(PPh3)2(CO).44 Similarly the bite angles of the N-C
chelates are similar (9 84.90(9)°, 10 85.08(8)°, 11
85.06(10)°, 12 85.54(9)°). The metallocyclic rings are
essentially planar and coplanar with the phenyl ring
bound to Rh. The N-phenyl ring adopts an orientation
that is close to orthogonal to the metallocycle, thereby
minimimizing in-plane steric interactions. The N-C
distances (1.440(3)-1459(3) Å) are observed to be
slightly longer than that seen in the free ligand 2 (1.406-
(3) Å). Similarly, the P-N bond lengths in the Rh
complexes (9 1.610(2) Å, 10 1.613(2) Å, 11 1.616(3) Å,
12 1.605(2) Å) were longer than that observed in 2
(1.553(2) Å). These changes in N-C and P-N param-
eters are consistent with electron donation from N to
Rh. The Rh-N-P angles in 9-11 were similar at
115.17(12)°, 115.86(10)°, and 115.85(13)°, respectively.
In contrast, the corresponding angle in 12 of 112.45-
(10)° is smaller and may reflect the steric crowding as
a result of the presence of the i-Pr groups on the N-aryl
ring. The Rh-C distances in the Rh(COD) fragments
are not equivalent. Those trans to the aryl-carbon are
P h en yla te-P h osp h in im in e Liga n d Com p lexes.
These Li salts react with [Rh(µ-Cl)(COD)]2 in THF at
room temperature. The resulting complexes Rh(COD)-
(o-C6H4PPh2NR) (R ) Ph 9, 2,6-Me2C6H3 10, 3,5-
Me2C6H3 11, 2,6-i-Pr2C6H3 12) were characterized by
1
variety of techniques, including H, 13C{1H}, and 31P-
{1H} NMR spectroscopy, elemental analysis, and X-ray
diffraction studies (Scheme 1). The chemical shifts of
the 31P{1H} spectra of these complexes varied with
substitution on the N-phenyl ring, resulting in an
upfield shift with the presence of electron-donating
groups in the 2- and 6-positions. Substitution in the 3-
and 5-positions resulted in a 31P{1H} resonance very
similar to the unsubstituted compound 9. 13C{1H} NMR
(40) Dehnicke, K.; Weller, F. Coord. Chem. Rev. 1997, 158, 103-
169.
(41) Dehnicke, K.; Krieger, M.; Massa, W. Coord. Chem. Rev. 1999,
182, 19-65.
(42) Dehnicke, K.; Straehle, J . Polyhedron 1989, 8, 707-726.
(43) Steiner, A.; Stalke, D. Angew. Chem., Int. Ed. Engl. 1995, 34,
1752-1755.
(44) Krug, C.; Hartwig, J . F. J . Am. Chem. Soc. 2002, 124, 1674-
1679.

386 Organometallics, Vol. 23, No. 3, 2004
Chan et al.
F igu r e 2. ORTEP drawings of (a) 9, (b) 10, (c) 11, and (d) 12 with 30% thermal ellipsoids; hydrogen atoms have been
omitted for clarity. Selected bond distances (Å) and angles (deg): (a) 9: Rh(1)-N(1) 2.114(2), Rh(1)-C(1) 2.071(3), P(1)-
N(1) 1.610(2), N(1)-C(19) 1.445(3), Rh(1)-C(25) 2.097(3), Rh(1)-C(32) 2.106(3), Rh(1)-C(28) 2.225(3), Rh(1)-C(29) 2.207(3),
N(1)-Rh(1)-C(1) 84.90(9), P(1)-N(1)-Rh(1) 115.17(12). For comparison the corresponding data for 13 is provided: Ir-
(1)-N(1) 2.081(5), Ir(1)-C(1) 2.084(5), Ir(1)-C(25) 2.104(6), Ir(1)-C(26) 2.106(6), Ir(1)-C(30) 2.179(5), Ir(1)-C(29) 2.195(6),
P(1)-N(1) 1.628(5), N(1)-C(19) 1.440(7), N(1)-Ir(1)-C(1) 84.77(19), C(19)-N(1)-Ir(1) 126.6(3), P(1)-N(1)-Ir(1) 115.8(3);
(b) 10: Rh(1)-N(1) 2.125(2), Rh(1)-C(1) 2.066(3), P(1)-N(1) 1.613(2), N(1)-C(19) 1.445(3), Rh(1)-C(27) 2.235(3), Rh(1)-
C(28) 2.214(3), Rh(1)-C(31) 2.113(3), Rh(1)-C(32) 2.089(3), N(1)-Rh(1)-C(1) 85.08(8), P(1)-N(1)-Rh(1) 115.86(10), C(19)-
N(1)-Rh(1) 123.97(16); (c) 11: Rh(1)-C(1) 2.068(3), Rh(1)-C(31) 2.089(3), Rh(1)-C(30) 2.104(3), Rh(1)-N(1) 2.105(3),
Rh(1)-C(27) 2.196(3), Rh(1)-C(34) 2.235(3), P(1)-N(1) 1.616(3), N(1)-C(19) 1.459(4), C(1)-Rh(1)-N(1) 85.06(10), P(1)-
N(1)-Rh(1) 115.85(13), C(19)-N(1)-Rh(1) 124.47(19); (d) 12: Rh(1)-N(1) 2.140(2), Rh(1)-C(1) 2.057(3), P(1)-N(1) 1.605(2),
N(1)-C(19) 1.440(3), Rh(1)-C(31) 2.184(3), Rh(1)-C(32) 2.220(3), Rh(1)-C(35) 2.103(3), Rh(1)-C(36) 2.117(3), N(1)-Rh-
(1)-C(1) 85.54(9), P(1)-N(1)-Rh(1) 112.45(10), C(19)-N(1)-Rh(1) 124.00(15).
longer than those trans to the phosphinimine-N. For
example, in 9 the Rh(1)-C(28) and Rh(1)-C(29) dis-
tances are 2.225(3) and 2.207(3) Å, respectively, whereas
the Rh(1)-C(25) and Rh(1)-C(32) distances are 2.097(3)
and 2.106(3) Å. Similar differences were also observed
in 10-12. These variations are consistent with the
greater trans influence of the aryl-carbon in comparison
to that of N.
The reaction of compound 9 with 1.1 equiv of (CH2-
PPh2)2 resulted in replacement of the COD ligand,
affording the species Rh(PPh2CH2CH2PPh2)(o-C6H4-
1
PPh2NPh) (14, Scheme 1), as evidenced by H and 31P-
{1H} NMR spectroscopy. In particular, the 31P{1H}
spectrum showed three distinct signals with the ex-
pected Rh-P and P-P couplings. 31P NMR spectroscopy
also showed that compound 9 reacted with CH2Cl2 to
give two products in a ratio of ca. 8:1. The dominant
species 15 (Scheme 1) gave rise to two sets of reso-
nances, a doublet centered at 43.7 ppm (2J Rh-P ) 12 Hz)
and another doublet centered at 27.1 ppm (2J Rh-P ) 3
Hz), while the minor product 16 afforded a doublet
centered at 34.6 ppm (2J Rh-P ) 11 Hz) and a singlet
centered at 28.1 ppm. Variable-temperature 31P{1H}
NMR spectroscopy showed that the signals broadened
slightly upon cooling and the signals from 16 disap-
peared below -60 °C. This is consistent with an equi-
librium between these two species. To characterize the
major species, the reaction was repeated with CD2Cl2
In an analogous manner, the Ir analogue of 9,
compound 13, was prepared using [Ir(µ-Cl)(COD)]2
(Scheme 1). NMR data were consistent with the formu-
lation, and X-ray crystallographic data confirmed that
13 was found to be iso-structural to 9. Ir-C and Ir-N
distances were found to be 2.084(5) and 2.081(5) Å.
While the Ir-C bond distance is only slightly longer
than the corresponding Rh-C distances in 9, 10, and
12, the Ir-N is in fact slightly shorter. Nonetheless, the
Ir(COD) fragment exhibits Ir-C distances that follow
a pattern similar to those in the Rh complexes, as the
Ir-C bonds trans to aryl-C are longer (Ir(1)-C(30)
2.179(5) Å; Ir(1)-C(29) 2.195(6) Å) than those trans to
N (Ir(1)-C(25) 2.104(6) Å; Ir(1)-C(26) 2.106(6) Å).
These are similar to those observed in the related Ir
complex Ir(COD)((MeC6H4N)PPh2CH(PPh2NC6H4Me).45
2
and monitored by D NMR spectroscopy. This experi-
ment revealed the presence of a resonance at 4.2 ppm,
which we attribute to a methylene group in the major
product.
Although these data suggested oxidative addition of
CH2Cl2, this was only confirmed by an X-ray study in
which the formulation of 15 was confirmed to be [Rh-
(o-C6H4PPh2NPh)(CH2-o-C6H4PPh2NPh)(µ-Cl)2Rh(COD)]-
(45) Imhoff, P.; van Asselt, R.; Ernsting, J . M.; Vrieze, K.; Elsevier,
C. J .; Smeets, W. J . J .; Spek, A. L.; Kentgens, A. P. M. Organometallics
1993, 12, 1523-1536.

Anionic Phosphinimine-Chelate Rh and Ir Complexes
Organometallics, Vol. 23, No. 3, 2004 387
Sch em e 2
Sch em e 3
F igu r e 3. ORTEP drawing of 15 with 30% thermal
ellipsoids; hydrogen atoms have been omitted for clarity.
Selected bond distances (Å) and angles (deg): Rh(1)-C(26)
2.004(5), Rh(1)-C(19) 2.081(6), Rh(1)-N(2) 2.108(5), Rh(1)-
N(1) 2.152(5), Rh(1)-Cl(2) 2.5454(17), Rh(1)-Cl(1) 2.566-
(2), Rh(2)-C(54) 2.085(8), Rh(2)-C(57) 2.091(8), Rh(2)-
C(53) 2.096(7), Rh(2)-C(50) 2.112(9), Rh(2)-Cl(2) 2.397(2),
Rh(2)-Cl(1) 2.4007(18), P(1)-N(1) 1.617(5), P(2)-N(2)
1.603(5), N(1)-C(20) 1.436(8), N(2)-C(44) 1.438(8), C(26)-
Rh(1)-C(19) 90.4(2), C(26)-Rh(1)-N(2) 84.4(2), C(19)-
Rh(1)-N(2) 88.4(2), C(26)-Rh(1)-N(1) 98.1(2), C(19)-
Rh(1)-N(1) 89.7(2), N(2)-Rh(1)-N(1) 176.90(18), C(26)-
Rh(1)-Cl(2) 172.91(17), C(19)-Rh(1)-Cl(2) 94.86(17), N(2)-
Rh(1)-Cl(2) 90.90(13), N(1)-Rh(1)-Cl(2) 86.78(13), C(26)-
Rh(1)-Cl(1) 92.45(16), C(19)-Rh(1)-Cl(1) 174.19(17), N(2)-
Rh(1)-Cl(1) 86.78(14), N(1)-Rh(1)-Cl(1) 94.91(14), Cl(2)-
Rh(1)-Cl(1) 81.93(5), Cl(2)-Rh(2)-Cl(1) 88.59(6), Rh(2)-
Cl(1)-Rh(1) 94.44(6), Rh(2)-Cl(2)-Rh(1) 95.04(6), P(1)-
N(1)-Rh(1) 119.2(3), P(2)-N(2)-Rh(1) 116.1(2), P(1)-
N(1)-Rh(1) 119.2(3), P(2)-N(2)-Rh(1) 116.1(2).
Sch em e 4
(15). This orange-colored, binucler Rh(I)-Rh(III) com-
plex (Figure 3) consists of a pseudo-octahedral Rh(III)
center and a pseudo-square-planar Rh(I) center. These
two Rh atoms are bridged by two Cl atoms. The Rh-Cl
distances reflect the differing oxidation states. The Rh-
(III)-Cl distances average 2.556(2) Å, while the Rh(I)-
Cl distances average 2.399(2) Å. The coordination
sphere of the Rh(I) is completed by a COD ligand. The
Rh-N distances in this fragment are similar to each
other and range from 2.085(8) to 2.112(9) Å. One of the
original aryl-phosphinimine ligands is bound to the Rh-
(III) center; in addition another such ligand has a
methylene group inserted into the Rh-Caryl bond. As
expected, the Rh-Caryl distance is slightly shorter
(2.004(5) Å) than the Rh-CH2 distance of 2.081(6) Å.
This Rh-CH2 distance is similar to that found in RhI-
(C6H5)((Ph2PCH2)2C6H3CH2) (2.069(4) Å).46 It is also
noteworthy that unlike related Rh(I) species described
by Milstein et al., the methylene-arene fragment in 15
shows no evidence of arenium character.47,48 The C
atoms bound to Rh are cis (C(26)-Rh(1)-C(19) 90.4-
(2)°) and trans to the bridging Cl atoms, leaving the two
phosphinimine N atoms trans to each other with Rh-N
distances of 2.108(5) and 2.152(5) Å and a N-Rh-N
angle of 176.90(18)°.
Having unambiguously established the nature of 15,
it was proposed that 16 was a minor product arising
from the equilibrium depicted in Scheme 2, although
this could not be unequivocally confirmed, as 16 could
not be isolated. As for the mechanism of the formation
of 15, this is the subject of speculation (Scheme 3). One
is tempted to suggest initial oxidative addition of CH2-
Cl2 to 9 affords a monometallic species containing a
RhCl(CH2Cl) fragment, as has been previous observed
in related systems.1-7 However attempts to spectro-
scopically observe such an intermediate were not suc-
cessful. If we speculate that this is the case however,
subsequent oxidation addition could afford a bimetallic
methylene-bridged species similar to those previously
reported.9,10 Such a complex would then undergo me-
thylene insertion in the Rh-Caryl bond and ligand
redistribution to give 15. Steric congestion could be the
driving force for this process. Although similar inser-
tions into Rh-L bonds have been found in other
systems,7,11-13 compound 15 represents the first case
where C-C bond formation has resulted.
(46) Cohen, R.; Van der Boom, M. E.; Shimon, L. J . W.; Rozenberg,
H.; Milstein, D. J . Am. Chem. Soc. 2000, 122, 7723-7734.
(47) Vigalok, A.; Rybtchinski, B.; Shimon, L. J . W.; Ben-David, Y.;
Milstein, D. Organometallics 1999, 18, 895-905.
(48) van der Boom, M. E.; Ben-David, Y.; Milstein, D. J . Am. Chem.
Soc. 1999, 121, 6652-6656.

388 Organometallics, Vol. 23, No. 3, 2004
Chan et al.
These salts react with [Rh(µ-Cl)(COD)]2 to form the
complexes Rh(COD)((N2C3H2)PPh2NR), R ) Ph 22, 2,6-
Me2C6H3 23, in 95% yields. The 31P NMR spectra of
these complexes show the typical downfield shift from
the ligand resonance, with the expected Rh-P coup-
lings. Similar to 9-13, NMR spectra for 22 and 23
showed resonances attributable to olefinic and methyl-
ene protons of the COD ligand as a result of the
asymmetry of the imidazolate-phosphinimine ligand. An
X-ray crystallographic study confirmed the structure of
23, in which cyclooctadiene and a phosphinimine-
imidazolate ligand are coordinated to a pseudo-square-
planar Rh(I) center. The Rh-imidazolate-N bond dis-
tance (2.070(2) Å) is significantly shorter (0.06 Å) than
the Rh-phosphinimine-N bond length presumably as
a result of the anionic nature of the imidazolate group.
It is noteworthy that this Rh-phosphinimine-N distance
(2.133(2) Å) is comparable to the M-Caryl distances seen
in 9-13 as well as to the Rh-N distances reported for
Rh(COD)(CH2PPh2(NC6H4Me)) (2.132(3) Å)49 and Rh-
(COD)((MeC6H4N)PPh2CHPPh2NH(C6H4Me)) (2.144(9)
Å).45 The Rh-imidazolate-N bond length (2.070(3) Å)
is slightly longer than the corresponding Rh-pyrro-
late-N distance found in Rh(COD)((NC5H4)CH2NHCH2-
(NC4H4)) (2.039(3) Å).50 Consistent with these differ-
ences in the Rh-N distances, the Rh-C bonds reflect
the greater trans influence of the imidazolate N.
F igu r e 4. ORTEP drawings of (a) asymmetric unit of 22
and (b) polymeric nature of 22 in solid state with 30%
thermal ellipsoids; hydrogen atoms have been omitted for
clarity. Selected bond distances (Å) and angles (deg):
Na(1)-O(1) 2.363(3), Na(1)-N(2) 2.425(3), Na(1)-N(3)
2.440(3), Na(1)-N(1) 2.460(3), P(1)-N(1) 1.575(2), N(1)-
C(13) 1.418(3), N(2)-C(21) 1.352(4), N(2)-C(22) 1.365(4),
N(3)-C(21) 1.354(3), N(3)-C(23) 1.361(4), O(1)-Na(1)-
N(2) 128.26(10), O(1)-Na(1)-N(3) 97.15(10), N(2)-Na(1)-
N(3) 130.60(9), O(1)-Na(1)-N(1) 103.35(10), N(2)-Na(1)-
N(1) 77.13(9), N(3)-Na(1)-N(1) 114.07(10), P(1)-N(1)-
Na(1) 114.04(12).
Compounds 22 and 23 did not react with CH2Cl2 even
after prolonged exposure. While one might invoke a
steric argument similar to that used above for 10 and
12 to explain the stability of 23, the stability of 22 is
enigmatic. Clearly the species 22 is sterically similar
to 9, and thus one might have anticipated oxidative
addition on that basis. This observation suggests that
electronic factors are influencing reactivity in this case.
To probe this question, DFT calculations were perform-
ed on the ligand-Rh model fragments [Rh((C6H4)PH2-
NH)] and [Rh((N2C3H2)PH2NH)]. The charge distribu-
tions were calculated using both Mulliken atomic charges
and natural population analysis (NPA). The calculated
charges are tabulated in Table 2. For example, the
Mulliken charge on Rh in the phenylate model is 0.004,
whereas it is 0.23 in the imidazolate case. The corre-
sponding NPA charges were found to be 0.14 and 0.35,
respectively. Although these methods afford differing
computed charges, there is consistency in the findingof
a higher positive charge on Rh in the imidazolate
complex. In addition, the calculated energies of the
orbital orthogonal to the Rh-L plane, that is, the
Treatment of 10 and 12 with CH2Cl2 showed no
evidence of reaction even after prolonged stirring. These
observations suggested that steric bulk at the 2,6-
position of the N-phenyl rings precludes oxidative
addition of the CH2Cl2 to the Rh center. In contrast,
reaction of 11 gave rise to several products with 31P-
{1H} NMR resonances in the range 47-28 ppm. At-
tempts to separate these products were unsuccessful.
It is clear that oxidative addition of CH2Cl2 occurs in
this case as well, again consistent with the steric
arguments.
Im id a zola te-P h osp h in im in e Liga n d Com p lexes.
Oxidation of the imidazole-phosphine 17 with organic
azides proceeds smoothly to give the corresponding
phosphinimines (N2C3H3)PPh2NR, R ) Ph 18, 2,6-
Me2C6H3 19, in high yields (>90%). NMR data con-
firmed these formulations. These ligands react with
NaH at 25 °C in THF to give the corresponding Na-
imidazolate-phosphinimines, 20 and 21, in good yields.
NMR spectroscopy was consistent with the formulation
of these salts as [Na(THF)((N2C3H2)PPh2NR)]n, R ) Ph
20, 2,6-Me2C6H3 21. The nature of 20 was confirmed
crystallographically (Figure 4a) to be polymeric in the
solid state, in which the imidazolate groups bridge
adjacent Na atoms (Figure 4b). The geometry about the
Na atom can be described as a distorted tetrahedral
coordination sphere of three N atoms and an O atom,
allowing for the distortion that results from the presence
of the imidazolate-phosphinimine-chelate with the bite
angle of 77.13(9)°. The Na-N bond lengths are all
similar, falling in the narrow range 2.425(3)-2.460(3)
Å.
2
pseudo-dz orbital, were found to be -0.16626 and
-0.14464 for the imidazole and phenylate models,
respectively. These data suggest that weaker donation
of electron density from the imidazolate fragment
2
results in a more stable dz orbital on Rh and thus a
metal center that is less prone to oxidative addition.
In summary, anionic-phosphinimine ligands based on
arylate or imidazolate-phosphinimines have been readily
employed to prepare Rh and Ir complexes. In some cases
these species undergo oxidative addition of CH2Cl2.
However, steric congestion above and below the plane
(49) Imhoff, P.; Nefkens, S. C. A.; Elsevier, C.; Goubitz, K.; Stam,
C. H. Organometallics 1991, 10, 1421-1431.
(50) De Bruin, B.; Kicken, R. J . N. A. M.; Suos, N. F. A.; Donners,
M. P. J .; Den Reijer, C. J .; Sandee, A. J .; De Gelder, R.; Smits, J . M.
M.; Gal, A. W.; Spek, A. L. Eur. J . Inorg. Chem. 1999, 1581-1592.

Anionic Phosphinimine-Chelate Rh and Ir Complexes
Organometallics, Vol. 23, No. 3, 2004 389
Ta ble 1. Cr ysta llogr a p h ic Da ta
2
9
10
11
12
formula
fw
a (Å)
b (Å)
c (Å)
C
26H24NP
C32H31NPRh
563.46
9.835(5)
11.331(6)
12.325(7)
79.137(10)
88.477(10)
77.591(10)
triclinic
P1h
C34H35NPRh
591.51
10.122(6)
20.056(11)
14.533(8)
C38H43NOPRh
663.61
21.924(12)
15.092(8)
10.022(5)
C38H43NPRh
647.61
9.927(5)
11.193(6)
15.544(8)
89.621(10)
85.158(9)
72.044(10)
triclinic
P1h
381.43
9.626(5)
12.325(7)
17.721(9)
â (deg)
92.604(10)
107.315(11)
95.361(10)
cryst syst
space group
V (Å3)
monoclinic
P2(1)/n
2100.4(19)
1.206
monoclinic
P2(1)/n
2817(3)
1.395
4
0.686
11 904
4018
monoclinic
P2(1)/c
3301(3)
1.335
4
0.596
13 754
4690
1317.3(12)
1.421
1636.7(15)
1.314
d(calc) (g cm-1
Z
)
4
2
2
abs coeff, µ (cm-1
)
0.142
8756
2334
253
0.730
5636
3736
316
0.597
7043
4655
370
no. of data collected
no. of data Fo2 > 3σ(Fo
)
2
no. of variables
334
379
R
Rw
GOF
0.0416
0.1165
1.023
0.0251
0.0683
0.982
0.0231
0.0611
0.942
0.0269
0.0915
0.830
0.0244
0.0630
0.929
13
15
21
23
formula
fw
a (Å)
b (Å)
c (Å)
C
32H31NPIr
C69H64Cl2N2P2Rh2
1259.88
10.871(6)
12.726(7)
22.878(12)
96.295(10)
98.239(10)
99.031(9)
triclinic
3065(3)
P1h
C30H35N3NaOP
500.54
9.167(5)
12.033(6)
25.300(13)
C31H33N3PRh
581.48
8.459(5)
9.056(5)
19.201(11)
80.602(12)
78.983(11)
73.660(10)
triclinic
1376.0(13)
P1h
652.75
9.826(5)
11.278(5)
12.306(6)
79.013(8)
88.295(8)
77.195(9)
triclinic
1305.3(11)
P1h
1.661
2
5.197
5508
3712
316
â (deg)
93.553(9)
cryst syst
V (Å3)
monoclinic
2785(2)
P21/c
1.210
4
0.141
11 614
3983
space group
d(calc) (g cm-1
)
1.365
1.403
Z
2
2
abs coeff, µ (cm-1
)
0.720
13 024
8675
694
0.703
5900
3899
325
no. of data collected
no. of data Fo2 > 3σ(Fo
)
2
no. of variables
318
R
Rw
GOF
0.0313
0.0799
1.042
0.0561
0.1347
1.014
0.0459
0.1274
0.979
0.0263
0.0626
0.947
Ta ble 2. DF T Com p u ta tion s of Atom ic Ch a r ge
Den sities
F igu r e 5. ORTEP drawing of 23 with 30% thermal
ellipsoids; hydrogen atoms have been omitted for clarity.
Selected bond distances (Å) and angles (deg): Rh(1)-N(2)
2.070(2), Rh(1)-C(29) 2.101(3), Rh(1)-C(28) 2.118(3), Rh-
(1)-N(1) 2.133(2), Rh(1)-C(25) 2.141(3), Rh(1)-C(24)
2.156(3), N(1)-P(1) 1.619(2), N(1)-C(13) 1.455(4), N(1)-
P(1) 1.619(2), N(2)-C(21) 1.362(3), N(2)-C(23) 1.369(4),
N(3)-C(21) 1.341(4), N(3)-C(22) 1.367(4), N(2)-Rh(1)-
N(1) 83.32(9), P(1)-N(1)-Rh(1) 116.57(12).
Rh((C6H4)PH2NH)
Rh((N3C3H2)PH2NH)
Mulliken
charges
NPA
charges
Mulliken
charges
NPA
charges
atom
atom
Rh
P
N
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
0.003533
0.635956
0.14891 Rh
1.38090
0.237838
0.633305
-0.79039
0.35340
1.35482
-1.26616
P
-0.781775 -1.26335 N(1)
0.042648 -0.03488 N(2)
-0.437103 -0.47418
-0.020848 -0.10116
-0.045419 -0.09691
-0.394773 -0.49003
0.196770 -0.07263
-0.190906 -0.2911
C(1)
-0.095233 -0.20598 C(2)
-0.150775 -0.26783 N(3)
-0.113726 -0.20494 C(3)
-0.166996 -0.50508
tively, oxidation addition is suppressed by electronic
perturbations to the ligand which diminish the charge
density at Rh. In furthering these studies we are
probing the effects of similar ligand perturbations on
the reactivity of Rh complexes in catalysis. The results
of these efforts will be reported in due course.
of the Rh(I) coordination sphere provided by ligand
substituents inhibits such oxidative addition. Alterna-

390 Organometallics, Vol. 23, No. 3, 2004
Chan et al.
Su p p or tin g In for m a tion Ava ila ble: Crystallographic
data. This material is available free of charge via the Internet
at http://pubs.acs.org.
Ack n ow led gm en t. Financial support from NSERC
of Canada, NOVA Chemicals Corporation, and the
ORDCF is gratefully acknowledged. J.D.M. and J.S.J.Mc.
are grateful for the award of an OGS scholarship.
D.W.S. is grateful for the award of Forschungpreis from
the Alexander von Humboldt Stiftung.
OM030539G