Neutral and cationic group 13 phosphinimine and phosphinimide complexes

Article abstract of DOI:10.1021/om9904044

Reactions of the silylphosphimines R₃PNSiMe₃ (R = i-Pr, Ph, Cy) with AlCl₃, AlMeCl₂, AlMe₂Cl, and AlMe₃ afford the compounds (i-Pr₃PNSiMe₃)AlCl₃ (1), (R

Full text of DOI:10.1021/om9904044

Organometallics 1999, 18, 4197-4204
4197
Neu tr a l a n d Ca tion ic Gr ou p 13 P h osp h in im in e a n d
P h osp h in im id e Com p lexes
Christopher M. Ong, Peggy McKarns, and Douglas W. Stephan*
Department of Chemistry and Biochemistry, School of Physical Sciences, University of
Windsor, Windsor, Ontario, Canada N9B 3P4
Received May 26, 1999
Reactions of the silylphosphimines R3PNSiMe3 (R ) i-Pr, Ph, Cy) with AlCl3, AlMeCl2,
AlMe2Cl, and AlMe3 afford the compounds (i-Pr3PNSiMe3)AlCl3 (1), (R3PNSiMe3)AlMeCl2
(R ) i-Pr, 2; Ph, 3; Cy, 4), (R3PNSiMe3)AlMe2Cl (R ) i-Pr, 5; Ph, 6; Cy, 7), and (R3PNSiMe3)-
AlMe3 (R ) i-Pr, 8; Ph, 9; Cy, 10). Reaction of R3PNH (R ) t-Bu, Cy, Ph) with AlMe2Cl and
AlMe3 afforded (R3PNH)AlMe2Cl (R ) Cy, 11; t-Bu, 12) and (Ph3PNH)AlMe3 (13), respectively.
The dimeric species [Me2Al(µ-NPt-Bu3)]2 (14) [AlCl2(µ-NPt-Bu3)]2 (15) were derived from
reactions of (t-Bu3PNH) and AlMe3 and t-Bu3PNLi and MeAlCl2, respectively. Reaction of
the bisphosphinimine salt LiCH(PPh2(NSiMe3))2 (16) with aluminum, gallium, and indium
halides yielded [CH(PPh2(NSiMe3))2]MCl2 (M ) Al, 17; Ga, 18; In, 19) while the analogous
species [CH(PPh2(NSiMe3))2]AlMe2 (20) was prepared via reaction of 16 with Me2AlCl. The
compounds [CH(PPh2(NSiMe3))2]MR2 (M ) Al, Bz, 21; M ) Ga, R ) Me, 22; Bz, 23; M ) In,
R ) Me, 24; Bz, 25) were readily prepared by treatment of 17-19 with the appropriate
alkylating reagents. The borane B(C6F5)3 reacts stoichiometrically with the adducts 8-10
to give the products [(R3PNSiMe3)AlMe2][MeB(C6F5)3] (R ) i-Pr, 26; Ph, 27; Cy, 28) while
treatment of 27 with PMe3 affords clean conversion to the salt [(Ph3PNSiMe3)2AlMe(PMe3)]-
[(MeB(C6F5)3)] (29). Similarly, species [Me2Al(µ-NPt-Bu3)2AlMe][MeB(C6F5)3] (30) and [Me2-
Al(µ-NPt-Bu3)2AlMe(PMe3)][MeB(C6F5)3] (31) were obtained from 14. Attempts to generate
the related ionic derivatives from 20-25 yielded unstable mixtures of products. Under mild
conditions these group 13 ionic species did not effect the polymerization of ethylene.
Crystallographic data are reported for compounds 1, 3, 6, 8, 11, 13-15, 18, and 20.
In tr od u ction
complexes of phosphinimides and shown that they can
act as effective catalysts for ethylene polymerization.11,12
While transition metal based catalyst systems continue
to be a fruitful area of study and development in
general, several groups have begun to examine the
potential of main-group Lewis acid species. The elec-
trophilic nature of such species combined with the
reactivity of the M-C bonds augurs well for insertion
chemistry and thus applications in catalysis. In this
vein, J ordan and co-workers13,14 have recently reported
the characterization of aluminum cationic complexes
incorporating aminotroponiminate, â-diketiminate, and
bisimidinate ligands. In addition, Smith et al. have
reported related diketiminato complexes.15 In this
paper, we describe the syntheses and structures of
phosphinimine complexes of group 13 metals. The
synthesis of zwitterionic and cationic species derived
from these compounds has been investigated and con-
sidered.
In efforts to develop new catalysts for olefin polym-
erization, a number of groups have focused attention
on complexes of non-cyclopentadienyl ligands. Of par-
ticular interest have been systems incorporating amide
and imine based ligands. The research groups of Mc-
Conville,1,2 Brookhart,3-8 and Gibson,9,10 among others,
have led the way in developing catalysts derived from
both early and late transition metal based complexes
of these ligands. In our own efforts, we have focused
attention on phosphinimide ligands. On the basis of the
concept of the steric analogy to cyclopentadienyl ligands,
we have recently investigated early transition metal
(1) Scollard, J . D.; McConville, D. H.; Vittal, J . J . Organometallics
1995, 14, 8.
(2) Scollard, J . D.; McConville, D. H. J . Am. Chem. Soc. 1996, 118,
10008.
(3) Killian, C. M.; Tempel, D. J .; J ohnson, L. K.; Brookhart, M. J .
Am. Chem. Soc. 1996, 118, 11664.
(4) J ohnson, L. K.; Killian, C. M.; Brookhart, M. J . Am. Chem. Soc.
1995, 117, 6414.
(11) Stephan, D. W.; Guerin, F.; Spence, R. E. v.; Koch, L.; Gao, X.;
Brown, S. J .; Swabey, J . W.; Wang, Q.; Xu, W.; Zoricak, P.; Harrison,
D. G. Organometallics 1999, 18, 2046.
(5) J ohnson, L. K.; Mecking, S.; Brookhart, M. J . Am. Chem. Soc.
1996, 118, 267.
(6) Rix, F. C.; Brookhart, M.; White, P. S. J . Am. Chem. Soc. 1996,
118, 4746.
(7) Mecking, S.; J ohson, L. K.; Wang, L.; Brookhart, M. J . Am. Chem.
Soc. 1998, 120, 888.
(8) Killian, C. M.; J ohnson, L. K.; Brookhart, M. Organometallics
1997, 16, 2005.
(9) Gibson, V. C.; Marshall, E. L.; Redshaw, C.; Clegg, W.; Elsegood,
M. R. J . J . Chem. Soc., Dalton Trans. 1996, 21, 4197.
(10) Coles, M. P.; Dalby, C. I.; Gibson, V. C.; Clegg, W.; Elsegood,
M. R. J . J . Chem. Soc., Chem. Commun. 1995, 1709.
(12) Stephan, D. W.; Stewart, J . C.; Guerin, F.; Spence, R. E. v.;
Xu, W.; Harrison, D. G. Organometallics 1999, 18, 1116.
(13) (a) Ihara, E.; Young, V. G.; J ordan, R. F. J . Am. Chem. Soc.
1998, 120, 8277. (b) Radzewich, C. E.; Coles, M. P.; J ordan, R. F. J .
Am. Chem. Soc. 1998, 120, 9384.
(14) (a) Coles, M. P.; J ordan, R. F. J . Am. Chem. Soc. 1997, 119,
8125. (b) Coles, M. P.; Swenson, D. C.; J ordan, R. F. Organometallics
1997, 16, 5183.
(15) Qian, B.; Ward, D. L.; Smith III, M. R. Organometallics 1998,
17, 3070.
10.1021/om9904044 CCC: $15.00 © 1999 American Chemical Society
Publication on Web 09/10/1999

4198 Organometallics, Vol. 18, No. 20, 1999
Ong et al.
m), 1.2 (12H, m), 0.5 (9H, s), -0.1 (9H, s), -0.4 (9H, s). 13C-
Exp er im en ta l Section
{1H} NMR (C6D6): δ 37.6 (d, ) 54.6 Hz), 27.6, 27.3 (d, |J C-P
|
) 10.9 Hz), 26.4, 6.8, 2.4. 31P NMR (C6D6): δ 49.6.
Gen er a l Da ta . All preparations were done under an
atmosphere of dry, O2-free N2 employing both Schlenk line
techniques and an Innovative Technologies or Vacuum Atmo-
spheres inert atmosphere glovebox. Solvents were purified
employing Grubb’s type column systems manufactured by
Innovative Technology. All organic reagents were purified by
conventional methods. 1H and 13C{1H} NMR spectra were
recorded on Bruker Avance-300 and -500 spectrometers oper-
ating at 300 and 500 MHz, respectively. Trace amounts of
protonated solvents were used as references, and chemical
shifts are reported relative to SiMe4. 31P, 11B, 27Al, and 19F
NMR spectra were recorded on a Bruker Avance-300. All NMR
spectra were recorded at 25 °C unless otherwise indicated.
Guelph Chemical Laboratories Inc., Guelph, Ontario, per-
formed combustion analyses. The compounds R3PNSiMe3, R3-
Syn t h esis of (R3P NH)AlMe2Cl (R ) Cy, 11; t-Bu , 12)
a n d (P h 3P NH)AlMe3 (13). These compounds were prepared
in a similar fashion with the appropriate substitution of
phosphinimine and aluminum reagent; thus, a single repre-
sentative synthesis is detailed. To a solution of Cy3PNH (0.03
g, 0.102 mmol) in benzene was added Me2AlCl (1.0 M, 0.102
mL, 0.102 mmol). The reaction mixture was stirred for 10 h
and then filtered. The remaining solvent was removed under
vacuum. Recrystallization of the product from benzene afforded
1
crystals. Yield: 83%. (11) H NMR (C6D6): δ 3.3 (3H, m), 1.8
(12H, m), 1.4 (6H, m), 1.2 (12H, m), 0.5 (1H, s), -0.4 (6H, s).
13C{1H} NMR (C6D6, 25 °C): δ 37.6 (d, |J H-H| ) 53.5 Hz), 27.8,
27.3 (d, |J H-H| ) 11.7 Hz), 26.3, -0.9. 31P NMR (C6D6): δ 52.5.
Anal. Calcd for C20H40PNAlCl: C, 61.92; H, 10.39. Found: C,
61.41; H, 10.62. (12) Yield: 64%. 1H NMR (C6D6): δ 1.0 (27H,
d, |J H-H| ) 13.5 Hz), -0.1 (6H, s), -0.3 (1H, s). 13C{1H} NMR
(C6D6): δ 39.2 (d, |J C-P| ) 44.2 Hz), 29.1, 9.3. 31P NMR
(C6D6): δ 69.4. (13) Yield: 75%. 1H NMR (C6D6): δ 7.7 (6H,
m), 7.1 (9H, m), 0.3 (1H, s), -0.4 (9H, s). 13C{1H} NMR
(C6D6): δ 136.1, 132.9, 131.6, 129.0, 5.1. 31P NMR (C6D6): δ
-0.4. Anal. Calcd for C21H25PNAl: C, 72.19; H, 7.21. Found:
C, 72.63; H, 7.14.
Syn th esis of [AlMe2(µ-NP t-Bu 3)]2 (14). To a solution of
t-Bu3PNH (0.03 g, 0.138 mmol) in benzene was added Me3Al
(2.0 M, 0.069 mL, 0.138 mmol). The reaction mixture was
refluxed for 10 h and then filtered. The remaining solvent was
removed under vacuum. Recrystallization of the product from
benzene afforded colorless crystals. Yield: 62%. 1H NMR
(C6D6): δ 1.4 (27H, d, |J H-H| ) 12.5 Hz), 0.0 (6H, s). 13C{1H}
NMR (C6D6): δ 41.0 (d, |J C-P| ) 49.0 Hz), 31.0, 15.5, 0.5. 31P
NMR (C6D6): δ 56.7. Anal. Calcd for C28H64P2N2Al2: C, 61.74;
H, 11.84; N, 5.14. Found: C, 61.20; H, 12.33; N, 5.04.
Syn th esis of [AlCl2(µ-NP t-Bu 3)]2 (15). To a solution of of
t-Bu3PNLi (0.062 g, 0.278 mmol) in benzene was added
MeAlCl2 (1.0 M, 0.28 mL, 0.278 mmol). The reaction mixture
was refluxed for 10 h and then filtered. The remaining solvent
was removed under vacuum. Recrystallization of the product
from benzene afforded colorless crystals. Yield: 67%. 1H NMR
(C6D6): δ 1.5 (54H, d, |J H-H| ) 13.0 Hz). 13C{1H} NMR (C6D6):
δ 39.2 (d, |J C-P| ) 45.5 Hz), 29.2. 31P NMR (C6D6): δ 66.5. Anal.
Calcd for C24H54P2N2A12Cl2: C, 51.70; H, 9.76. Found: C,
51.47; H, 9.66.
PNH (R ) i-Pr, Cy, Ph, t-Bu),16a and CH2(PPh2(NSiMe3))2
17
were prepared via literature methods. AlMeCl2, AlMe2Cl, and
AlMe3 were purchased from the Aldrich Chemical Co.
Syn th esis of (i-P r 3P NSiMe3)AlCl3 (1). To a solution of
i-Pr3PNSiMe3 (0.073 g, 0.295 mmol) in benzene was added
AlCl3 (0.040 g, 0.295 mmol). The reaction mixture was stirred
for 10 h and then filtered. The remaining solvent was removed
1
under vacuum to yield a white powder. Yield: 74%. H NMR
(C6D6): δ 3.0 (3H, m), 0.9 (18H, q, |J H-H| ) 8.5 Hz), 0.5 (9H,
s). 13C{1H} NMR (C6D6): δ 27.6 (d, |J C-P| ) 52.2 Hz), 17.5,
7.3. 31P NMR (C6D6): δ 66.2.
Syn th esis of (R3P NSiMe3)AlMeCl2 (R ) i-P r , 2; P h , 3;
Cy, 4), (R3P NSiMe3)AlMe2Cl (R ) i-P r , 5; P h , 6; Cy, 7),
a n d (R3P NSiMe3)AlMe3 (R ) i-P r , 8; P h , 9; Cy, 10). These
compounds were prepared in a similar fashion with the
appropriate substitution of phosphinimine and aluminum
reagent; thus, a single representative synthesis is detailed. To
a solution of i-Pr3PNSiMe3 (0.03 g, 0.121 mmol) in hexane was
added MeAlCl2 (1.0 M, 0.121 mL, 0.121 mmol). The reaction
mixture was stirred for 10 h and then filtered and the solvent
1
removed to afford a white powder. Yield: 71%. (2) H NMR
(C6D6): δ 2.8 (3H, m), 0.9 (18H, m), 0.5 (9H, s), 0.1 (3H, s).
13C{1H} NMR (C6D6): δ 27.4 (d, |J C-P| ) 45.7 Hz), 17.4, 7.0.
31P NMR (C6D6): δ 64.6. Anal. Calcd for C13H33PNSiAlCl2: C,
1
43.33; H, 9.23. Found: C, 43.08; H, 9.51. (3) Yield: 99%. H
NMR (C6D6): δ 7.7 (6H, m), 7.0 (12H, m), 0.3 (9H, s), -0.5
(3H, s). 13C{1H} NMR (C6D6): δ 134.4, 133.3, 128.9, 128.5, 14.3,
4.9, -1.0. 31P NMR (C6D6): δ 34.5. (4) Yield: 83%. 1H NMR
(C6D6): δ 2.8 (3H, m), 1.9 (6H, m), 1.5 (12H, m), 1.1 (12H, m),
Gen er a tion of of LiCH(P P h 2(NSiMe3))2 (16). To a solu-
tion of CH2(PPh2(NSiMe3))2 (0.071 g, 0.127 mmol) in THF was
added n-butyllithium (2.5 M, 0.5 mL, 0.127 g). The reaction
was stirred for 12 h and filtered. The remaining solvent was
removed under vacuum to yield a lime yellow compound.
0.5 (9H, s), 0.2 (3H, s). 13C{1H} NMR (C6D6): δ 37.7 (d, |J C-P
|
) 52.2 Hz), 27.7, 27.1 (d, |J C-P| ) 12.2 Hz), 7.2, -1.2. 31P NMR
(C6D6): δ 55.3. (5) Yield: 71%. 1H NMR (C6D6): δ 2.7 (3H,
sept, |J H-H| ) 7.5 Hz), 0.9 (18H, q, |J H-H| ) 7.3 Hz), 0.4 (9H,
s), 0.0 (6H, s), 13C{1H} NMR (C6D6): δ 27.2(3H, d, |J C-P| )
54.4 Hz), 17.5, 6.9, -1.1. 31P NMR (C6D6): δ 61.5. (6) Yield:
1
Yield: 78%. H NMR (C6D6): δ 7.7 (8H, m), 7.1 (12H, m), 3.6
(1H, m), 0.1 (18H, s). 13C{1H} NMR (C6D6): δ 142.2 (d, |J C-P
|
1
99%. H NMR (C6D6): δ 7.7 (6H, m), 7.0 (12H, m), 0.3 (9H, s),
) 95.8 Hz), 131.6 (t, |J C-P| ) 3.8 Hz), 129.4, 127.8, 23.8 (t,
|J C-P| ) 129 Hz), 4.5. 31P NMR (C6D6): δ 17.5.
-0.4 (6H, s). 13C{1H} NMR (C6D6): δ 134.3, 133.3, 133.0, 128.7,
4.8, -1.4. 31P NMR (C6D6): δ 32.5. (7) Yield: 73%. H NMR
1
Syn th esis of [CH(P P h 2(NSiMe3))2]MCl2 (M ) Al, 17; Ga ,
18; In , 19). These complexes were prepared in a similar
manner, and thus only a single representative preparation is
described. To a solution of 16 (0.082 g, 0.145 mmol) in benzene
was added a solution of AlCl3 (0.020 g, 0.145 mmol). The
mixture was stirred for 12 h and filtered. The remaining
solvent was removed under vacuum to yield a white powder.
(17) Yield: 91%. 1H NMR (C6D6): δ 7.8 (8H, m), 6.9 (12H, m),
4.0 (1H, t, |J P-H| ) 3.75), 0.4 (18H, s). 13C{1H} NMR (C6D6):
δ 133.1 (d, |J C-P| ) 51.6 Hz), 132.4 (t, |J C-P| ) 3.08 Hz), 131.1,
128.3, 27.4 (t, |J C-P| ) Hz), 4.2. 31P NMR (C6D6): δ 24.3. (18)
(C6D6): δ 2.8 (3H, m), 1.9 (6H, m), 1.6 (12H, m), 1.2 (12H, m),
0.5 (9H, s), 0.1 (6H, s). 13C{1H} NMR (C6D6): δ 37.7 (d, |J C-P
|
) 52.9 Hz), 27.7, 27.1 (d, |J C-P| ) 12.4 Hz), 26.3, 6.9, -1.4. 31
P
NMR (C6D6): δ 53.2. (8) Yield: 72%. 1H NMR (C6D6): δ 2.4
(3H, m), 0.9 (18H, q, |J H-H| ) 7.3 Hz), 0.4 (9H, s), -0.2 (9H,
s). 13C{1H} NMR (C6D6): δ 26.8 (d, |J C-P| ) 55.5 Hz), 17.4,
6.8, 1.6. 31P NMR (C6D6): δ 57.9. Anal. Calcd for C15H39
-
PNSiAl: C, 56.39; H, 12.30. Found: C, 56.58; H, 11.94. (9)
1
Yield: 83%. H NMR (C6D6): δ 7.7 (6H, m), 7.0 (9H, m), 0.2
(9H, s), -0.4 (9H, s). 13C{1H} NMR (C6D6): δ 134.3, 132.7,
130.9, 128.7, 4.9, -1.3. 31P NMR (C6D6): δ 29.2. (10) Yield:
67%. 1H NMR (C6D6): δ 2.5 (3H, m), 1.9 (6H, m), 1.5 (12H,
1
Yield: 71%. H NMR (C6D6): δ 7.8 (8H, m), 7.0 (12H, m), 4.0
(1H, t, |J P-H| ) 12.82), 0.4 (18H, s). 13C{1H} NMR (C6D6): δ
134.7 (d, |J C-P| ) 86 Hz), 132.6 (t, |J C-P| ) 4.4 Hz), 131.3, 128.4,
29.5 (t, |J C-P| ) 117.4 Hz), 4.3. 31P NMR (C6D6): δ 32.3. Anal.
Calcd for C31H39P2N2Si2GaCl2: C, 53.31; H, 5.63. Found: C,
53.54; H, 5.91. (19) Yield: 87%. 1H NMR (C6D6): δ 7.7 (8H,
(16) For reviews of known phosphinimine and phosphinimide
complexes see: (a) Dehnicke, K.; Weller, F. Coord. Chem. Rev. 1997,
158, 103. (b) Dehnicke, K.; Kreiger, M.; Massa, W. Coord. Chem. Rev.
1999, 182, 19.

Group 13 Phosphinimine and Phosphinimide Complexes
Organometallics, Vol. 18, No. 20, 1999 4199
m), 7.0 (12H, m), 2.7 (1H, br t), 0.3 (18H, s). 13C{1H} NMR
-90.6 (t, |J B-F| ) 20.3 Hz). (28) 1H NMR (CD2Cl2): δ 1.9 (12H,
m), 1.8 (3H, m), 1.5 (6H, m), 1.3 (12H, m), 0.6 (9H, s), 0.5 (3H,
s), -0.2 (6H, s). 13C{1H} NMR (CD2Cl2): δ 152.0, 148.9, 140.8,
137.6, 38.3 (d, |J C-P| ) 52.0 Hz), 29.7, 28.6 (d, |J C-P| ) 15.9
Hz), 27.5, 15.4, 5.7, 3.8. 31P NMR (CD2Cl2): δ 57.1. 11B NMR
(CD2Cl2): δ -15.3. 27Al NMR (CD2Cl2): δ 59.2. 19F NMR (CD2-
Cl2): δ -55.9 (d, |J B-F| ) 23.1 Hz), -88.1 (t, |J B-F| ) 19.7 Hz),
-90.7 (t, |J B-F| ) 16.9 Hz).
(C6D6): δ 133.0, 132.3 (t, |J C-P| ) 3.2 Hz), 131.2, 128.3 (t, |J C-P
) 3.75 Hz), 41.8 (t, |J C-P| ) 69.8 Hz), 3.6. 31P NMR (C6D6): δ
32.4.
|
Syn th esis of [CH(P P h 2(NSiMe3))2]AlMe2 (20). To a solu-
tion of 17 (0.116 g, 0.206 mmol) in benzene was added Me2-
AlCl (1.0 M, 0.21 mL, 0.206 mmol). The mixture was stirred
for 12 h and filtered. The remaining solvent was removed
1
Syn th esis of [(P h 3P NSiMe3)AlMe2(P Me3)][MeB(C6F 5)3]
(29). To a solution of 27 (0.053 g, 0.06 mmol) in a 50/50
benzene/hexane solution was added PMe3 (0.006 mL, 0.06
mmol) in a similar solution. The reaction mixture was stirred
for 0.5 h and followed by decanting of the solvent. The
remaining solvent was removed under vacuum to yield a light
under vacuum to yield a white powder. Yield: 79%. H NMR
(C6D6): δ 7.6 (8H, m), 6.9 (12H, m), 3.5 (1H, t, |J P-H| ) 6.6
Hz), 0.2 (18H, s), 0.2 (6H, s). 13C{1H} NMR (C6D6): δ 136.5 (d,
|J C-P| ) 100.8 Hz), 132.3 (t, |J C-P| ) 4.1 Hz), 130.6,128.3, 25.2
(t, |J C-P| ) 122.1 Hz), 4.8. 31P NMR (C6D6): δ 28.7. Anal. Calcd
for C33H45P2N2Si2Al: C, 64.47; H, 7.38; N, 4.56. Found: C,
64.32; H, 7.27; N, 4.11.
1
yellow oil. H NMR (CD2Cl2): δ 7.7 (6H, m), 7.7 (9H, m), 0.9
(9H, d, |J P-H| ) 6.9 Hz), 0.5 (3H, s), 0.1 (9H, s), -0.7 (6H, s).
13C{1H} NMR (CD2Cl2): δ 150.2, 147.1, 139.5, 138.4, 136.2,
135.0 (d, |J C-P| ) 12.5 Hz), 133.9 (d, |J C-P| ) 10.2 Hz), 130.0,
126.9 (d, |J C-P| ) 99.9 Hz), 11.5 (d, |J C-P| ) 18.6 Hz), 4.2, 1.6,
1.6. 31P NMR (CD2Cl2): δ 33.9, -47.6. 11B NMR (CD2Cl2): δ
-15.3. 27Al NMR (CD2Cl2): δ 62.3. 19F NMR (CD2Cl2): δ -55.8
(d, |J B-F| ) 22.56), -88.0 (t, |J B-F| ) 20.59), -90.6 (t, |J B-F| )
21.7 Hz).
Syn th esis of [Me2Al(µ-NP t-Bu 3)2AlMe][MeB(C6F5)3] (30).
To a solution of B(C6F5)3 (0.066 g, 0.129 mmol) in a 50/50
benzene/hexane solution was added a solution of compound
14 (0.070 g, 0.129 mmol). The reaction mixture was stirred
for 0.5 h and followed by decanting of the solvent. The
remaining solvent was removed under vacuum to yield a light
Syn th esis of [CH(P P h 2(NSiMe3))2]MR2 (M ) Al, Bz, 21;
M ) Ga , R ) Me, 22; Bz, 23; R ) In , R ) Me, 24; Bz, 25).
These complexes were prepared in a similar manner employing
either benzylmagnesium bromide or methylmagnesium chlo-
ride, and thus only a single representative preparation is
described. To a solution of 17 (0.090 g, 0.137 mmol) in benzene
was added BzMgCl (1.0 M, 0.27 mL, 0.270 mmol). The mixture
was stirred for 12 h and filtered. The remaining solvent was
removed under vacuum to a yield white powder. (21) Yield:
1
81%. H NMR (C6D6): δ 7.5 (8H, m), 7.4 (4H, d, |J P-H| ) 7.7
Hz), 7.3 (4H, t, |J P-H| ) 7.5 Hz), 7.2 (2H, m), 7.0 (8H, m), 6.9
(4H, m), 3.0 (1H, t, |J P-H| ) 6.8), 2.5 (4H, s), 0.0 (18H, s). 13C-
{1H} NMR (C6D6): δ 148.5, 135.5 (d, |J C-P| ) 60.7 Hz), 132.3
(d, |J C-P| ) 6.2 Hz), 130.6, 129.6, 128.6, 128.1, 127.5, 121.9,
25.4 (t, |J C-P| ) 69.2 Hz), 5.1. 31P NMR (C6D6): δ 29.8. (22)
yellow oil. 1H NMR (CD2Cl2): δ 1.6 (3H, s), 1.5 (54H, d, |J H-H
|
) 13.5 Hz), 0.5 (3H, s), -0.2 (6H, s). 13C{1H} NMR (CD2Cl2):
δ 150.4, 147.2, 138.9, 135.6, 40.7 (d, |J C-P| ) 45.9 Hz), 31.7,
29.6, 10.0, 0.4. 31P NMR (CD2Cl2): δ 67.1. 11B NMR (CD2Cl2):
δ -15.3. 27Al NMR (CD2Cl2): δ 56.8. 19F NMR (CD2Cl2): δ
-55.8 (d, |J B-F| ) 22.6 Hz), -88.0 (t, |J B-F| ) 19.7 Hz), -90.6
(t, |J B-F| ) 19.7 Hz).
1
Yield: 86%. H NMR (C6D6): δ 7.6 (8H, m), 6.9 (12H, m), 3.4
(1H, br t), 0.4 (18H, s), -0.1 (6H, s). 13C{1H} NMR (C6D6): δ
135.5 (m), 132.1, 130.4, 128.1, 29.5 (t, |J C-P| ) 107.4 Hz), 4.8.
31P NMR (C6D6): δ 25.6. Anal. Calcd for C33H45P2N2Si2Ga: C,
60.28; H, 6.90; N, 4.26. Found: C, 60.02; H, 6.67; N, 4.08. (23)
1
Yield: 83%. H NMR (C6D6): δ 7.7 (8H, m), 7.5 (4H, m), 6.9
(12H, m), 6.8 (6H, m), 3.2 (1H, m), 2.1 (4H, s), 0.4 (18H, s).
13C{1H} NMR (C6D6): δ 146.3, 135.2 (d, |J C-P| ) 99.3 Hz),
132.2, 131.3, 128.7, 128.3, 128.0, 122.5, 70.6, 32.1 (t, |J C-P| )
Syn t h esis of [AlMe2(µ-NP t-Bu 3)2AlMe(P Me3)][MeB-
(C6F 5)3] (31). To a solution of 19 (0.070 g, 0.137 mmol) in CH2-
Cl2 was added PMe3 (0.005 mL, 0.137 mmol). The reaction
mixture was stirred for 0.5 h and followed by decanting of the
solvent. The remaining solvent was removed under vacuum
to yield a light-yellow oil. 1H NMR (CD2Cl2): δ 1.5 (57H, d,
|J P-H| ) 13.2 Hz), 1.3 (9H, d, |J P-H| ) 5.6 Hz), 0.5 (3H, s), -0.3
(6H, s). 13C{1H} NMR (CD2Cl2): δ 150.3, 147.2, 139.5, 138.5,
136.3, 135.3, 40.2 (d, |J C-P| ) 42 Hz), 30.7, 29.5, 14.9, 2.6. 31P
NMR (CD2Cl2): δ 65.4, -49.8. 11B NMR (CD2Cl2): δ -15.3.
27Al NMR (CD2Cl2): δ 60.5. 19F NMR (CD2Cl2): δ -55.7 (d,
1
102.7 Hz), 3.9. 31P NMR (C6D6): δ 25.4. (24) Yield: 78%. H
NMR (C6D6): δ 7.6 (8H, m), 7.0 (12H, m), 3.4 (1H, br t), 0.4
(18H, s), -0.2 (6H, s). 13C{1H} NMR (C6D6): δ 136.0, 132.2,
130.3, 128.0, 29.4 (t, |J C-P| ) 106.6 Hz), 5.1. 31P NMR (C6D6):
δ 25.6. Anal. Calcd for C33H45P2N2Si2In: C, 56.41; H, 6.46; N,
1
3.99. Found: C, 56.26; H, 6.23; N, 3.71. (25) Yield: 73%. H
NMR (C6D6): δ 7.3 (8H, m), 7.2 (8H, m), 7.1 (2H, m), 7.0 (12H,
m), 2.1 (4H, s), 3.2 (1H, m), 0.5 (18H, s). 13C{1H} NMR (C6D6):
δ 146.2, 136.4, 135.6, 132.2, 130.2, 128.7, 128.2, 127.3, 122.4,
28.6 (t, |J C-P| ) 108.1 Hz), 5.1. 31P NMR (C6D6): δ 25.4.
Syn th esis of [(R3P NSiMe3)AlMe2][MeB(C6F 5)3] (R )
i-P r , 26; P h , 27; Cy, 28). These compounds were prepared in
a similar fashion with the appropriate substitution of phos-
phinimine and aluminum reagent; thus, a single representa-
tive synthesis is detailed. To a solution of B(C6F5)3 (0.069 g,
0.134 mmol) in a 50/50 benzene/hexane solution was added 8
(0.043 g, 0.134 mmol) in a similar solution mixture. The
reaction mixture was stirred for 0.5 h and followed by
decanting of the solvent. The remaining solvent was removed
|J B-F| ) 23.1 Hz), -87.9 (t, |J B-F| ) 20.3 Hz), -90.5 (t, |J B-F
|
) 21.4 Hz).
X-r a y Da ta Collection a n d Red u ction . X-ray-quality
crystals of 1, 3, 6, 8, 13-15, 18, and 20 were obtained directly
from the preparation 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 collecting a hemisphere of data
in 1329 frames with 10 s exposure times. Crystal data are
summarized in Table 1. The observed extinctions were con-
sistent 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 recollecting 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 correc-
tion based on redundant data was applied to each data set.
Subsequent solution and refinement was performed using the
SHELXTL solution package operating on a SGI Challenge
mainframe computer with remote X-terminals or PC employ-
1
under vacuum to yield a light-yellow oil. (26) H NMR (CD2-
Cl2): δ 2.5 (3H, m), 1.3 (9H, d, |J H-H| ) 7.2 Hz), 1.4 (9H, d,
|J H-H| ) 7.2 Hz), 0.6 (9H, s), 0.5 (3H, s), -0.2 (6H, s). 13C{1H}
NMR (CD2Cl2): δ 150.2, 147.0, 138.8, 135.6, 25.6 (d, |J C-P| )
53.9 Hz), 17.3, 3.6, 10.1, 1.2. 31P NMR (CD2Cl2): δ 66.6. 11B
NMR (CD2Cl2): δ -15.3. 27Al NMR (CD2Cl2): δ 62.1. 19F NMR
(CD2Cl2): δ -55.8 (d, |J B-F| ) 23.1 Hz), -87.9 (t, |J B-F| ) 20.3
Hz), -90.6 (t, |J B-F| ) 21.2 Hz). (27) 1H NMR (CD2Cl2): δ 7.8
(6H, m), 7.7 (9H, m), 0.5 (3H, s), 0.2 (9H, s), -0.6 (6H, s). 13C-
{1H} NMR (CD2Cl2): δ 150.4, 147.2, 138.9, 133.9, 136.2, 132.4,
131.8, 125.1, 10.0, 2.5, 1.2. 31P NMR (CD2Cl2): δ 33.3. 11B NMR
(CD2Cl2): δ -15.3. 27Al NMR (CD2Cl2): δ 62.3. 19F NMR (CD2-
Cl2): δ -55.9 (d, |J B-F| ) 22.9 Hz), -88.0 (t, |J B-F| ) 20.8 Hz),
2
2
ing X-emulation. The reflections with Fo > 3σFo were used
in the refinements.

4200 Organometallics, Vol. 18, No. 20, 1999
Ta ble 1. Cr ysta llogr a p h ic P a r a m eter sa
Ong et al.
1
3
6
8
11
13
14
15
18
20
formula
NPSi
formula wt 380.76
a, Å
b, Å
C12H30AlCl3- C25H30AlCl2- C23H30AlCl- C15H39AlN- C20H40AlCl- C21H25AlNP C28H66Al2N2 C24H54Al2- C31H39Cl2Ga- C33H45Cl2Al-
NPSi
501.44
11.486(3)
15.496(4)
NPSi
441.97
10.0480(1)
23.0088(3)
PSi
NP
Cl4N2P2
628.39
13.316(4) 12.164(6)
N2P2Si2
N2P2Si2
614.81
12.240
21.09900(10)
15.0698(2)
112.2760(10)
3601.41(5)
P21/c
319.51
387.93
349.37
546.73
16.4295(3)
698.38
9.057(3)
14.296(3)
15.618(3)
92.73(3)
2020.1(8)
9.2831(19) 12.18710(10) 20.302(2)
14.594(2) 15.2395(2)
31.366(5) 12.6737(2)
8.6588(11) 13.48230(10) 16.339(4) 20.921(7)
c, Å
30.737(12) 11.1174(2)
95.019(14) 103.7790(10) 91.20(2)
5449.7(29) 2496.22(6) 4248.4(13) 2353.27(5)
23.725(5)
15.30300(10) 15.225(6) 15.076(10)
113.11(3)
â, deg
91.2510(10)
V, Å3
4170.7(11) 3389.73(7)
Pca21
3312.5(18) 3529(3)
space group P21/n
Cc
P21/n
P21/c
P21/n
Pca21
Pbcm
P21/c
d(calcd),
g cm-1
Z
1.252
1.222
1.176
0.999
1.095
1.113
1.071
1.260
1.315
1.134
4
8
4
8
4
8
4
4
4
4
µ, cm-1
0.626
0.386
9429
0.309
12471
0.219
4066
0.271
11595
0.176
12158
0.198
9811
0.524
15770
1.113
17734
0.235
18396
no. of data 10086
collected
no. of data 3521
used
4976
309
4330
253
3319
343
4065
217
4874
451
4296
307
3022
166
6144
361
6304
361
no. of
172
variables
R, %
Rw, %
GOF
0.0423
0.1348
1.079
0.0730
0.1664
1.160
0.0436
0.1297
1.055
0.0636
0.1786
1.375
0.0583
0.1916
1.648
0.0558
0.1490
1.214
0.0652
0.1881
1.558
0.0869
0.1300
1.451
0.0326
0.0987
0.829
0.0370
0.1258
1.080
a
2
All data collected at 24 °C with Mo KR radiation (λ ) 0.710 69 Å). R ) ∑||Fo| - |Fc||/∑|Fo|. Rw ) [∑(|Fo| - |Fc|)2|/∑|Fo| ]0.5
.
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.18,19 The heavy atom positions were determined
using direct methods employing either of the SHELXTL direct
method routines. 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 ω(|Fo| -
|Fc|)2, where the weight ω 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. 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
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 1. The locations
of the largest peaks in the final difference Fourier map
calculation as well as the magnitude of the residual electron
densities in each case were of no chemical significance.
Positional parameters, hydrogen atom parameters, thermal
parameters, and bond distances and angles have been depos-
ited as Supporting Information.
F igu r e 1. ORTEP drawings of 1; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Al(1)-N(1), 1.902(2) Å; Al(1)-Cl(2), 2.1313(12) Å;
Al(1)-Cl(3), 2.1372(13) Å; Al(1)-Cl(1), 2.1481(13) Å; P(1)-
N(1), 1.646(2) Å; N(1)-Si(1), 1.804(2) Å; N(1)-Al(1)-Cl-
(2), 112.51(8)°; N(1)-Al(1)-Cl(3), 109.36(8)°; Cl(2)-Al(1)-
Cl(3), 108.02(6)°; N(1)-Al(1)-Cl(1), 116.62(8)°; Cl(2)-
Al(1)-Cl(1), 102.47(5)°; Cl(3)-Al(1)-Cl(1), 107.35(6)°; P(1)-
N(1)-Si(1), 124.00(12)°; P(1)-N(1)-Al(1), 123.92(12)°; Si(1)-
N(1)-Al(1), 112.07(11)°.
Sch em e 1
Resu lts a n d Discu ssion
Syn th esis. Reactions of the silylphosphimines R3-
PNSiMe3 (R ) i-Pr, Ph, Cy) with the aluminum Lewis
acids AlCl3, AlMeCl2, AMe2Cl, and AlMe3 are in general
straightforward acid-base reactions, resulting in the
formation of the corresponding donor-acceptor adducts.
In this manner the compounds (i-Pr3PNSiMe3)AlCl3 (1),
(R3PNSiMe3)AlMeCl2 (R ) i-Pr, 2; Ph, 3; Cy, 4), (R3-
PNSiMe3)AlMe2Cl (R ) i-Pr, 5; Ph, 6; Cy, 7), and (R3-
PNSiMe3)AlMe3 (R ) i-Pr, 8; Ph, 9; Cy, 10) were readily
prepared and isolated (Scheme 1). NMR spectroscopic
data are consistent with these formulations. As is
typical, a downfield shift of the 31P resonance upon
ligand coordination of the phosphinimine nitrogen to
aluminum is observed. Crystallographic data were
obtained for compounds 1, 3, 6, and 8 (Figures 1-4).
The structural features of these molecules are as
expected with a pseudotetrahedral geometry about the
aluminum centers. The Al-N distances range from
1.902(2) to 1.968(2) Å. These distances are significantly
(17) Ong, C. M.; Stephan, D. W. J . Am. Chem. Soc. 1999, 121, 2939.
(18) Cromer, D. T.; Mann, J . B. Acta Crystallogr., Sect. A 1968, A24,
324.
(19) Cromer, D. T.; Mann, J . B. Acta Crystallogr., Sect. A 1968, A24,
390.

Group 13 Phosphinimine and Phosphinimide Complexes
Organometallics, Vol. 18, No. 20, 1999 4201
F igu r e 4. ORTEP drawing of one of the two independent
molecules of 8 in the asymmetric unit; 30% thermal
ellipsoids are shown. Hydrogen atoms have been omitted
for clarity. Al(1)-C(15), 1.982(9) Å; Al(1)-C(14), 1.990(10)
Å; Al(1)-C(13), 1.991(11) Å; Al(1)-N(1), 2.022(4) Å; Si(1)-
N(1), 1.762(6) Å; P(1)-N(1), 1.606(6) Å; C(15)-Al(1)-C(14),
110.3(5)°; C(15)-Al(1)-C(13), 112.7(4)°; C(14)-Al(1)-
C(13), 100.1(4)°; C(15)-Al(1)-N(1), 107.9(3)°; C(14)-Al-
(1)-N(1), 111.8(3)°; C(13)-Al(1)-N(1), 113.9(3)°; P(1)-
N(1)-Si(1), 125.8(2)°; P(1)-N(1)-Al(1), 124.0(3)°; Si(1)-
N(1)-Al(1), 110.1(3)°.
F igu r e 2. ORTEP drawing of one of the two independent
molecules of 3 in the asymmetric unit; 30% thermal
ellipsoids are shown. Hydrogen atoms have been omitted
for clarity. Al(1)-N(1), 1.93(2) Å; Al(1)-C(22), 1.96(2) Å;
Al(1)-Cl(1), 2.138(9) Å; Al(1)-Cl(2), 2.214(8) Å; P(1)-N(1),
1.58(2) Å; N(1)-Al(1)-C(22), 115.2(7)°; N(1)-Al(1)-Cl(1),
107.5(6)°; C(22)-Al(1)-Cl(1), 113.4(6)°; N(1)-Al(1)-Cl(2),
108.2(5)°; C(22)-Al(1)-Cl(2), 102.7(6)°; Cl(1)-Al(1)-Cl(2),
109.5(4)°; P(1)-N(1)-Si(1), 121.8(9)°; P(1)-N(1)-Al(1),
120.8(9)°; Si(1)-N(1)-Al(1), 117.3(8)°.
bond distances are typical, averaging 1.781(4) Å. The
geometry about the nitrogen atoms is approximately
trigonal planar with P-N-Si angles ranging from
121.8(9)° to 126.6(2)°.
In contrast to the above Lewis acid-base chemistry,
attempts to form analogous complexes with t-Bu3-
PNSiMe3 with all of the aluminum species Al(Me)3-nCln
resulted in no reaction under a variety of conditions.
The failures of adduct formation in these cases are
attributed to the steric crowding as the cone angle of
the (t-Bu3P) fragment is significantly larger than those
of the other phosphines.
This view is also supported by the observation that
for the parent phosphinimines R3PNH, where the steric
crowding is alleviated by the removal of the trimethyl-
silyl substituent, adduct formation occurs readily. In
this vein, reaction of R3PNH (R ) t-Bu, Cy, Ph) with
AlMe2Cl and AlMe3 afforded the synthesis of (R3PNH)-
AlMe2Cl (R ) Cy, 11; t-Bu, 12) and (Ph3PNH)AlMe3
(13), respectively. Spectroscopic data as well as crystal-
lographic data for 11 and 13 confirmed the above
formulations (Figures 5 and 6). In general the geom-
etries of these adducts are similar to those observed for
1, 3, 6, and 8. Reduced steric congestion about nitrogen
is reflected in the shorter Al-N bond distances, in 11
(1.892(2) Å) and 13 (1.665(5) Å) as well as the P-N-Al
angles in 11 (142.0(2)°) and 13 (152.2(4)°) which are
significantly greater than those observed for the trim-
ethylsilylphosphimine adducts described above. While
the P-N distance in 11 (1.623(2) Å) falls in the range
observed for 1, 3, 6, and 8, the P-N distance in 13
averages 1.520(5) Å, suggesting stronger P-N multiple
bonding.
F igu r e 3. ORTEP drawings of 6; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Al(1)-N(1), 1.968(2) Å; Al(1)-C(23), 1.982(3) Å; Al(1)-
C(22), 1.993(2) Å; Al(1)-Cl(1), 2.2150(12) Å; Si(1)-N(1),
1.781(2) Å; P(1)-N(1), 1.612(2) Å; N(1)-Al(1)-C(23), 113.93-
(10)°; N(1)-Al(1)-C(22), 109.93(10)°; C(23)-Al(1)-C(22),
114.34(14)°; N(1)-Al(1)-Cl(1), 103.86(7)°; C(23)-Al(1)-Cl-
(1), 103.21(10)°; C(22)-Al(1)-Cl(1), 110.84(10)°; P(1)-
N(1)-Si(1), 125.52(12)°; P(1)-N(1)-Al(1), 117.00(11)°; Si-
(1)-N(1)-Al(1), 117.11(10)°.
longer that those found in iminoaluminum dimer [CpAl-
20
(µ-Naryl)]2 (1.796(2) Å, 1.811(3) Å) but in the range
of those found in the diketiminato derivatives described
by Smith et al.15 Comparing the i-Pr3PNSiMe3 adducts
1 and 8, the Al-N bond distances in 1 (1.646(2) Å) are
significantly shorter than those found in 8 (1.763(6) Å)
consistent with the greater electron-withdrawing nature
of chloride versus methyl. Among 1, 3, 6, and 8, the Al-
Cl and Al-C distances average 2.155(9) and 1.98(3) Å,
respectively. These distances are typical of the Al-Cl
In early studies, Schmidbaur et al.24-27 showed that
aluminum-phosphinimine adducts were not thermally
stable. For the complexes (Me3PNSiMe3)AlMe3 ther-
molysis resulted in ligand liberation. In contrast, alu-
distances in [Cp*AlCl(µ-Cl)]2 and [Cp*AlMe(µ-Cl)]2,22
21
and the Al-C distances are similar to those in the
complexes (CH(C(CH3)NR)2)Al(CH3)2 (R ) tolyl, 2,6-i-
Pr2C6H4)15 and the terminal Al-Me bond in Cp2AlMe
(1.943(5) Å).23 P-N multiple bonding is reflected by the
P-N bond distance range of 1.58(2)-1.651(14) Å. Si-N
(22) Koch, H. J .; Schulz, S.; Roesky, H. W.; Noltmeyer, M.; Schmidt,
H. G.; Heine, A.; Herst-Irmer, R.; Stalke, D.; Scheldrick, G. Chem. Ber.
1992, 125, 1107.
(23) Fisher, J . D.; Wei, M. Y.; Willett, R.; Shapiro, P. J . Organome-
tallics 1994, 13, 3324.
(20) Fisher, J . D.; Shapiro, P.; Yap, G. P. A.; Rheingold, A. L. Inorg.
Chem. 1996, 35, 271.
(21) Schonberg, P. R.; Paine, R. T.; Campana, C. F. J . Am. Chem.
Soc. 1979, 101, 7726.
(24) Schmidbaur, H.; Wolfsberger, W. J . Organomet. Chem. 1969,
16, 188.
(25) Schmidbaur, H.; Schwirten, K.; Pickel, H. H. Chem. Ber. 1969,
102, 567.

4202 Organometallics, Vol. 18, No. 20, 1999
Ong et al.
F igu r e 7. ORTEP drawings of 14; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Al(1)-N(2), 1.925(7) Å; Al(1)-N(1), 1.940(7) Å; Al(1)-C(25),
1.944(10) Å; Al(1)-C(26), 1.989(9) Å; Al(1)-Al(2), 2.704(2)
Å; Al(2)-N(1), 1.914(7) Å; Al(2)-N(2), 1.936(7) Å; Al(2)-
C(27), 2.020(9) Å; Al(2)-C(28), 2.026(11) Å; P(1)-N(1),
1.604(3) Å; P(2)-N(2), 1.604(3) Å; N(2)-Al(1)-N(1), 90.6-
(3)°; N(2)-Al(1)-C(25), 112.3(4)°; N(1)-Al(1)-C(25), 111.8-
(4)°; N(2)-Al(1)-C(26), 115.7(3)°; N(1)-Al(1)-C(26), 116.2-
(3)°; C(25)-Al(1)-C(26), 109.3(5)°; N(1)-Al(2)-N(2), 91.1(3)°;
N(1)-Al(2)-C(27), 111.6(2)°; N(2)-Al(2)-C(27), 110.4(3)°;
N(1)-Al(2)-C(28), 115.7(4)°; N(2)-Al(2)-C(28), 114.7(4)°;
C(27)-Al(2)-C(28), 111.8(5)°; P(1)-N(1)-Al(2), 135.7(5)°;
P(1)-N(1)-Al(1), 135.1(5)°; Al(2)-N(1)-Al(1), 89.14(12)°;
P(2)-N(2)-Al(1), 135.4(5)°; P(2)-N(2)-Al(2), 135.7(5)°; Al-
(1)-N(2)-Al(2), 88.92(12)°.
F igu r e 5. ORTEP drawings of 11; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Al(1)-N(1), 1.892(2) Å; Al(1)-C(20), 1.990(3) Å; Al(1)-
C(19), 1.995(3) Å; Al(1)-Cl(1), 2.2166(12) Å; P(1)-N(1),
1.623(2) Å; N(1)-Al(1)-C(20), 113.90(14)°; N(1)-Al(1)-
C(19), 106.1(2)°; C(20)-Al(1)-C(19), 115.8(2)°; N(1)-Al-
(1)-Cl(1), 104.30(9)°; C(20)-Al(1)-Cl(1), 108.18(13)°; C(19)-
Al(1)-Cl(1), 107.89(14)°; P(1)-N(1)-Al(1), 142.0(2)°.
Sch em e 2
F igu r e 6. ORTEP drawing of one of the two independent
molecules of 13 in the asymmetric unit; 30% thermal
ellipsoids are shown. Hydrogen atoms have been omitted
for clarity. One set of the disordered Al-bound carbon
positions are depicted: Al(1)-N(1), 1.672(4) Å; P(1)-N(1),
1.513(4) Å; P(1)-N(1)-Al(1), 152.8(3)°.
minum-phosphinimide derivatives of formulation [X2-
Al(µ-NPR3)]2 (X ) Br, Me) were derived via reaction of
the tin-phosphinimine reagents R3PNSnMe3 with AlMe3
or upon heating the adduct (Me3PNSiMe3)AlBr3 to 215
°C. In a similar manner, the adducts 1-10 are not
thermally stable. However, upon heating to 80-90 °C
loss of Me3SiCl is not observed; rather the phosphin-
imine ligand is simply liberated. Similarly, heating of
adducts 11-13 also resulted in ligand liberation. How-
ever, heating the reaction mixture of (t-Bu3PNH) and
AlMe3 to 80 °C for 10 h resulted in the formation of the
species [Me2Al(µ-NPt-Bu3)]2 (14) in 62% isolated yield
(Scheme 2). Monitoring the reaction mixture by 31P
NMR spectroscopy revealed the initial formation of the
adduct (t-Bu3PNH)AlMe3 as evidenced by the observa-
tion of the resonance at 68.25 ppm. Upon heating, this
signal is replaced with the resonance at 56.72 ppm
attributed to 14. The dimeric formulation of 14 in which
two phosphinimide ligands bridge two aluminum cen-
ters has been confirmed by X-ray crystallography (Fig-
ure 7). The coordination sphere of each aluminum center
is a significantly distorted pseudotetrahedral geometry
with Al-N and Al-C bond distances averaging 1.929-
(7) and 1.994(10) Å, respectively, with C-Al-C and
N-Al-C angles of 110.6(5)° and 113.6(5)°. This bridged
geometry results in an Al-Al separation of 2.704(2) Å.
The four-membered Al2N2 core gives rise to N-Al-N
and Al-N-Al angles averaging 90.9(3)° and 89.03(12)°,
respectively. Correspondingly, the planarity at the
nitrogen atoms results in average P-N-Al angles of
135.5(5)°.
Attempts to prepare the chloromethyl analogue of 14
were undertaken via the reaction of t-Bu3PNLi and
MeAlCl2. NMR data of the isolated colorless, crystalline
product 15 revealed no evidence of aluminum-bound
methyl groups. X-ray crystallographic studies of 15
confirmed the dimeric formulation as [AlCl2(µ-NPt-
Bu3)]2 (Figure 8). Although not anticipated it appears
that methyl for halide redistribution is favored during
this reaction as 15 is isolated in 67% yield based on Al
and ligand. The general structural features of 15 are
very similar to those described above for 14 and to those
reported for [AlCl2(µ-NPPh3)]2 by Dehnicke et al.16 The
bridging phosphinimide groups give rise to Al-N dis-
tances that are shorter in 15 than in 14, averaging
1.888(4) Å. This is consistent with the presence of the
electron-withdrawing chlorides on aluminum. The Al-
(26) Schmidbaur, H.; Wolfsberger, W.; Schwirten, K. Chem. Ber.
1969, 102, 556.
(27) Wolfsberger, W.; Schmidbaur, H. J . Organomet. Chem. 1969,
17, 41.

Group 13 Phosphinimine and Phosphinimide Complexes
Organometallics, Vol. 18, No. 20, 1999 4203
F igu r e 8. ORTEP drawings of 15; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Al(1)-N(2), 1.888(4) Å; Al(1)-N(1), 1.887(4) Å; Al(1)-Cl-
(1), 2.126(2) Å; Al(1)-Cl(2), 2.148(2) Å; Al(1)-Al(1), 2.633-
(3) Å; P(1)-N(1), 1.623(5) Å; P(2)-N(2), 1.627(5) Å; N(1)-
Al(1), 1.887(4) Å; N(2)-Al(1), 1.888(4) Å; N(2)-Al(1)-N(1),
91.42(17)°; N(2)-Al(1)-Cl(1), 115.76(17)°; N(1)-Al(1)-Cl-
(1), 116.71(17)°; N(2)-Al(1)-Cl(2), 109.93(17)°; N(1)-Al-
(1)-Cl(2), 112.44(18)°; Cl(1)-Al(1)-Cl(2), 109.53(11)°; P(1)-
N(1)-Al(1), 135.76(12)°; P(1)-N(1)-Al(1), 135.76(12)°;
Al(1)′-N(1)-Al(1), 88.4(2)°; P(2)-N(2)-Al(1), 135.77(11)°;
P(2)-N(2)-Al(1), 135.77(11)°; Al(1)′-N(2)-Al(1), 88.4(2)°.
F igu r e 9. ORTEP drawings of 18; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Ga(1)-N(1), 1.926(2) Å; Ga(1)-N(2), 1.930(2) Å; Ga(1)-
Cl(2), 2.200(2) Å; Ga(1)-Cl(1), 2.2006(10) Å; Si(1)-N(1),
1.771(2) Å; P(1)-N(1), 1.637(2) Å; P(2)-N(2), 1.639(2) Å;
N(1)-Ga(1)-N(2), 113.53(9)°; N(1)-Ga(1)-Cl(2), 107.34-
(8)°; N(2)-Ga(1)-Cl(2), 106.46(7)°; N(1)-Ga(1)-Cl(1),
111.60(7)°; N(2)-Ga(1)-Cl(1), 112.37(7)°; Cl(2)-Ga(1)-Cl-
(1), 104.89(4)°; P(1)-N(1)-Si(1), 126.99(13)°; P(1)-N(1)-
Ga(1), 109.71(12)°; Si(1)-N(1)-Ga(1), 121.85(12)°; P(2)-
N(2)-Si(2), 127.51(13)°; P(2)-N(2)-Ga(1), 109.36(11)°;
Si(2)-N(2)-Ga(1), 120.53(11)°.
Sch em e 3
F igu r e 10. ORTEP drawings of 20; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Al(1)-N(2), 1.952(2) Å; Al(1)-N(1), 1.959(2) Å; Al(1)-C(33),
1.986(2) Å; Al(1)-C(32), 1.996(2) Å; Si(1)-N(1), 1.765(2)
Å; Si(1)-C(26), 1.870(2) Å; Si(1)-C(27), 1.874(2) Å; Si(1)-
C(28), 1.883(2) Å; Si(2)-N(2), 1.767(2) Å; P(1)-N(1), 1.640-
(2) Å; P(2)-N(2), 1.637(2) Å; N(2)-Al(1)-N(1), 108.96(7)°;
N(2)-Al(1)-C(33)°, 111.76(9); N(1)-Al(1)-C(33), 111.58-
(8)°; N(2)-Al(1)-C(32), 106.78(8)°; N(1)-Al(1)-C(32),
106.01(8)°; C(33)-Al(1)-C(32), 111.46(9)°; P(1)-N(1)-Si-
(1), 125.94(9)°; P(1)-N(1)-Al(1), 111.94(8)°; Si(1)-N(1)-
Al(1), 119.52(8)°; P(2)-N(2)-Si(2), 125.18(9)°; P(2)-N(2)-
Al(1), 112.77(8)°; Si(2)-N(2)-Al(1), 120.59(8)°.
Cl distances in 15 average 2.137(2) Å, and the corre-
sponding Al-Al separation is 2.633(3) Å.
An alternative approach to group 13 phosphinimine
derivatives involves the use of the bidentate anion of
LiCH(PPh2(NSiMe3))2 (16). Reaction of 16 with alumi-
num, gallium, and indium halides readily gives the four-
coordinate complexes of the form [CH(PPh2(NSiMe3))2]-
MCl2 (M ) Al, 17; Ga, 18; In, 19) (Scheme 3). In the
case of 18, this formulation was confirmed by X-ray
crystallography (Figure 9). The pseudotetrahedral co-
ordination sphere about Ga is defined by the two
phosphinimine nitrogen atoms (Ga-Nav ) 1.928(2) Å)
and the two chlorides (Ga-Clav ) 2.203(2) Å). The “bite
angle” of the bisphosphinimine anion is 113.53(9)°, while
the Cl-Ga-Cl angle is 104.89(4)°. The ligand geometry
is as expected, although it is noteworthy that the central
carbon and Ga atoms are displaced from the N2P2 plane
by 0.60 and 0.75 Å, respectively.
The analogous species [CH(PPh2(NSiMe3))2]AlMe2
(20) was prepared via reaction of 16 with Me2AlCl. This
formulation was confirmed by X-ray crystallography
(Figure 10). The pseudotetrahedral coordination sphere
about Al is similar to that of the Ga atom in 18. The
Al-Nav and Al-Cav distances in 20 average 1.955(2) and
1.991(2) Å, respectively. The pseudochair conformation
of the chelate ring in 20 is similar to that seen in 18,
with the central carbon and Ga atoms displaced from
the N2P2 plane by 0.63 and 0.77 Å, respectively. A
variety of other alkyl and aryl derivatives, including
[CH(PPh2(NSiMe3))2]MR2 (M ) Al, Bz, 21; M ) Ga, R
) Me, 22; Bz, 23; R ) In, R ) Me, 24; Bz, 25), were
readily prepared by treatment of the halide compounds
17-19 with the appropriate lithium or Grignard re-
agents. 1H, 13C, and 31P NMR data as well as elemental
analyses of a representative sampling of these species
were consistent with these formulations.
Ion ic Sa lts. Attempts to generate related zwitterionic
and/or cationic derivatives from 20-25 proved to yield
highly sensitive species. In general, the aluminum and
gallium species gave unstable mixtures of products upon

4204 Organometallics, Vol. 18, No. 20, 1999
Ong et al.
reactions with the borane B(C6F5)3. Similarly reaction
of 24 with the trityl borate Ph3C[B(C6F5)4] gave a
mixture of unidentified, unstable products as evidenced
by 31P NMR.
NMR spectrum of 30 is temperature invariant to -80
°C. Moreover, it is noteworthy that, even in the presence
of a large excess of borane, compound 30 does not
undergo further reaction. This lack of reactivity is in
contrast to that of the related titanium complex (t-Bu3-
PN)2TiMe(µ-MeB(C6F5)3)11 which readily converts to
(t-Bu3PN)2Ti(µ-MeB(C6F5)3)2.28 As with compound 27,
the zwitterionic species 30 reacts with PMe3 to give the
complex salt [Me2Al(µ-NPt-Bu3)2AlMe(PMe3)][MeB-
(C6F5)3] (31) as confirmed by the spectroscopic data.
Preliminary screening of these group 13 zwitterionic
systems for their ability to catalyze ethylene polymer-
ization was undertaken. The species 28, 29, and 31
failed to effect polymerization under mild conditions of
25 °C and 1 atm of the ethylene. This may result from
the inherent strength of the Al-C bond and thus its
resistance to facile insertion.
In contrast, the Lewis acidic borane B(C6F5)3 reacts
stoichiometrically with the phosphinimine adducts 8-10
in a facile manner to form the ionic species. These
species proved to have extreme sensitivity. While this
precluded the acquisition of elemental analytical data,
1H, 13C, 31P, 11B, 27Al, and 19F NMR spectral data were
consistent with the formulation of these products as [(R3-
PNSiMe3)AlMe2][MeB(C6F5)3] (R ) i-Pr, 26; Ph, 27; Cy,
28) (Scheme 1). Particularly characteristic of these
species were the broadened 1H NMR resonance at-
tributed to the borane-bound methyl group at ap-
proximately 0.48 ppm and the single resonance attrib-
utable to the Al-bound methyl groups between -0.2 and
-0.6 ppm. These observations, together with the fact
that these resonances are temperature invariant to -80
°C, infer that migration of the borane among the methyl
groups does not occur. Treatment of 27 with PMe3
affords clean conversion to the salt [(Ph3PNSiMe3)2-
AlMe(PMe3)][MeB(C6F5)3] (29) as confirmed by the NMR
data. For example, the 31P NMR spectrum of 29 shows
resonances at 33.9 and -47.6 ppm attributable to the
phosphinimine and coordinated phosphine ligands, re-
spectively. The similarity of these data to those observed
for 27 suggests that these compounds are discrete ions
in solutions, although this has not been confirmed via
conductivity measurements.
Su m m a r y
The preparation and structural and spectroscopic
features of a variety of group 13 complexes of phosphin-
imine ligands have been described. The ionic derivatives
demonstrate the expected electrophilic nature, which
augurs well for the olefin polymerization catalysts.
Nonetheless, the present phosphinimine and phosphin-
imide group 13 systems are not operative as ethylene
polymerization catalysts under ambient conditions.
Under more forcing conditions, J ordan et al. have
effected ethylene polymerization by aluminum catalysts
at 80 °C.13,14
In a similar vein, stoichiometric treatment of the
dimeric species 14 with the borane B(C6F5)3 results in
the formation of the ionic product [Me2Al(µ-NPt-Bu3)2-
AlMe][MeB(C6F5)3] 30 (Scheme 2) as evidenced by the
NMR data. It is noteworthy that the resonances at-
tributable to the terminal methyl groups on the unal-
tered aluminum center are observed at 1.57 ppm while
the resonances for the bridging and terminal methyl
groups at the zwitterionic aluminum center occur at
Ack n ow led gm en t. Financial support from NSERC
of Canada is gratefully acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Crystallographic
data and NMR spectra for 26-31. This material is available
free of charge via the Internet at http://pubs.acs.org.
OM9904044
1
0.46 and -0.21 ppm, respectively. As with 28, the H
(28) Stephan, D. W.; Guerin, F., submitted for publication.