Neutral and Cationic Group 13 Alkyl and Hydride Complexes of a Phosphinimine-Amide Ligand

Article abstract of DOI:10.1021/om0306776

The phosphinimine-amine ligand 1 reacts with MR₃ (M = Al, Ga; R = Me, H) with loss of RH to form the complexes (i-Pr₂C ₆H₃N)C(Me)CHPPh₂(NC₆H ₃-i-Pr₂)MMe₂ (M

Full text of DOI:10.1021/om0306776

Organometallics 2004, 23, 1819-1824
1819
Neu tr a l a n d Ca tion ic Gr ou p 13 Alk yl a n d Hyd r id e
Com p lexes of a P h osp h in im in e-Am id e Liga n d
J ason D. Masuda, Denise M. Walsh, Pingrong Wei, and Douglas W. Stephan*
Department of Chemistry & Biochemistry, University of Windsor, Windsor,
Ontario, Canada N9B3P4
Received December 1, 2003
The phosphinimine-amine ligand 1 reacts with MR3 (M ) Al, Ga; R ) Me, H) with loss
of RH to form the complexes (i-Pr2C6H3N)C(Me)CHPPh2(NC6H3-i-Pr2)MMe2 (M ) Al (2), Ga
(3)) and (i-Pr2C6H3N)C(Me)CHPPh2(NC6H3-i-Pr2)AlH2 (4). Subsequent reactions of 2 and 3
with [Ph3C][B(C6F5)4] afforded [(i-Pr2C6H3N)C(Me)CHPPh2(NC6H3-i-Pr2)MMe][B(C6F5)4] (M
) Al (5), Ga (6)), while similar reactions of 2 and 3 with B(C6F5)3 gave [(i-Pr2C6H3N)C(Me)-
CHPPh2(NC6H3-i-Pr2)MMe][B(C6F5)3Me] (M ) Al (8), Ga (9)). The analogous reactions of 4
with [Ph3C][B(C6F5)4] and B(C6F5)3 resulted in the formation of [(i-Pr2C6H3N)C(Me)CHPPh2-
(NC6H3-i-Pr2)AlH][B(C6F5)4] (10) and [(i-Pr2C6H3N)C(Me)CHPPh2(NC6H3-i-Pr2)AlH][B(C6F5)3H]-
(11), respectively. Crystallographic studies of 1, 2, 4, and [(i-Pr2C6H3N)C(Me)CHPPh2(NC6H3-
i-Pr2)AlMe(OEt2)][B(C6F5)4] (7) are reported.
In tr od u ction
effort to exploit such steric crowding, we sought to
prepare group 13 complexes where the steric bulk would
preclude dimerization or higher aggregation. Thus, in
this paper, we describe the preparation and character-
ization of a series of monometallic neutral and cationic
group 13 alkyl and hydride complexes incorporating a
phosphinimine-amide ligand. Structural data are pre-
sented, and the implications are considered. Related
systems are described in the preceding paper by Piers
and co-workers.11
A recent review has summarized the use of â-diket-
imine ligands in the synthesis of metal complexes.1
J ordan and co-workers have employed a bulky â-diket-
iminine ligand with 2,6-diisopropylphenyl substituents
(NacNac) on the N atoms to prepare base-free mono-
meric aluminum cations.2,3 The groups of Roesky and
Power have also utilized this ligand to isolate unique
Al(I)4 and Ga(I)5 complexes as well as Al(III) dihydrox-
ide,6 dithiol,7 and diselinide8 complexes. In targeting
related ligands that provide thermal stability, additional
sites for modification, and a spectroscopic handle, we
have recently focused attention on the mixed-donor
ligands incorporating phosphinimine donors and other
N- or C-based donors.9,10 We have also shown that, in
late-transition-metal complexes, phosphinimine-imido
ligands are stronger donors than their â-diketimide
analogues.9 Our previous studies also showed that, in
the absence of other sterically demanding ligands,
phosphinimine-amide ligands provide significantly in-
creased steric congestion about the metal center as a
result of the inclusion of the R2PNR′ fragment. In an
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 a Vacuum Atmospheres inert-atmosphere
glovebox. Solvents were purified employing a Grubbs-type
solvent purification system manufactured by Innovative Tech-
nology. Deuterated solvents were purified using the appropri-
ate techniques. All organic reagents were purified by conven-
tional methods. 1H, 31P{1H}, 11B{1H}, 19F{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 (in ppm) are
reported relative to SiMe4. 31P{1H}, 11B{1H}, and 19F{1H} NMR
spectra were referenced to external 85% H3PO4, BF3‚Et2O, and
CFCl3, respectively. Combustion analyses were done in house
employing a Perkin-Elmer CHN analyzer. The ligand (i-
Pr2C6H3NH)C(Me)CHPPh2(NC6H3-i-Pr2) (1) was prepared by
literature methods.10 Single crystals of 1 were grown over
several weeks by the slow evaporation of a toluene solution.
The deuterated alane (Et2O)AlD3 was prepared in situ by the
method outlined by Carey et al. for (Et2O)AlH3.12
* To whom correspondence should be addressed. E-mail: Stephan@
uwindsor.ca.
(1) Bourget-Merle, L.; Lappert, M. F.; Severn, J . R. Chem. Rev. 2002,
102, 3031-3066.
(2) Radzewich, C. E.; Coles, M. P.; J ordan, R. F. J . Am. Chem. Soc.
1998, 120, 9384-9385.
(3) Radzewich, C. E.; Guzei, I. A.; J ordan, R. F. J . Am. Chem. Soc.
1999, 121, 8673-8674.
(4) Cui, C.; Roesky, H. W.; Schmidt, H.-G.; Noltemeyer, M.; Hao,
H.; Cimpoesu, F. Angew. Chem., Int. Ed. 2000, 39, 4274-4276.
(5) Hardman, N. J .; Eichler, B. E.; Power, P. P. Chem. Commun.
2000, 1991-1992.
Syn th esis of (i-P r 2C6H3N)C(Me)CHP P h 2(NC6H3-i-P r 2)-
MMe2 (M ) Al (2), Ga (3)) a n d (i-P r 2C6H3N)C(Me)CHP P h 2-
(NC6H3-i-P r 2)AlH2 (4). These compounds were prepared in a
similar fashion using AlMe3, GaMe3, and AlH3‚NEt2Me, re-
(6) Bai, G.; Peng, Y.; Roesky, H. W.; Li, J .; Schmidt, H.-G.; Nolte-
meyer, M. Angew. Chem., Int. Ed. 2003, 42, 1132-1135.
(7) J ancik, V.; Peng, Y.; Roesky, H. W.; Li, J .; Neculai, D.; Neculai,
A. M.; Herbst-Irmer, R. J . Am. Chem. Soc. 2003, 125, 1452-1453.
(8) Cui, C.; Roesky, H. W.; Hao, H.; Schmidt, H.-G.; Noltemeyer,
M. Angew. Chem., Int. Ed. 2000, 39, 1815-1817.
(9) Spencer, L. P.; Altwer, R.; Wei, P.; Gelmini, L.; Gauld, J .;
Stephan, D. W. Organometallics 2003, 22, 3841-3854.
(10) Masuda, J . D.; Wei, P.; Stephan, D. W. Dalton 2003, 3500-
3505.
(11) Welch, G. C.; Piers, W. E.; Parvez, M.; McDonald, R. Organo-
metallics 2004, 23, 1811.
(12) Carey, D. T.; Mair, F. S.; Pritchard, R. G.; Warren, J . E.; Woods,
R. J . Dalton 2003, 3792-3798.
10.1021/om0306776 CCC: $27.50 © 2004 American Chemical Society
Publication on Web 03/11/2004

1820 Organometallics, Vol. 23, No. 8, 2004
Masuda et al.
spectively, and thus only one preparation is detailed. To a
solution of 1 (0.321 g, 0.556 mmol) in 5 mL of n-pentane was
added AlMe3 (0.042 g) in 5 mL of n-pentane. A white
precipitate formed over several minutes, and the mixture was
stirred overnight. Volatiles were removed in vacuo, yielding a
white powder. The material was purified by dissolving in a
minimum of hot n-heptane and cooling the solution to room
temperature, affording large colorless blocks of 2 (210 mg) in
tube, 30 mg (0.047 mmol) of 4 and 1 equiv of [Ph3C][B(C6F5)4]
(44 mg) were combined in approximately 0.6 mL of C6D5Cl.
The contents were shaken until completely dissolved, and
NMR experiments showed quantitative formation of 5. 5: 1H
NMR (C6D5Cl) 7.03-7.46 (m, 16H, o-, m-, p-PPh2, m-, p-Dip),
2
4.32 (d, | J P-H| ) 21 Hz, 1H, CHP), 3.14 (sept, |J H-H| ) 7 Hz,
2H, CH), 2.82 (sept, |J H-H| ) 7 Hz, 2H, CH), 1.81 (s, 3H, Me),
1.31 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 1.25 (d, |J H-H| ) 7 Hz, 6H,
i-Pr), 0.92 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 0.37 (d, |J H-H| ) 7 Hz,
6H, i-Pr), -0.70 (s, 3H, AlMe); 13C{1H} NMR (C6D5Cl) 170.7,
149.8 (br), 149.2, 147.8 (br), 146.3 (d, |J P-C| ) 4 Hz), 144.9,
139.5 (br), 137.7 (br), 135.7 (br), 135.0, 134.4, 134.1, 132.4 (d,
|J P-C| ) 10 Hz), 127.9-129.6 (m, obscured by C6D5Cl), 125.6-
126.3 (m, obscured by C6D5Cl), 125.4, 124.9, 124.0, 72.2 (d,
1
60% yield. 2: H NMR 7.50-7.57 (m, 4H, o-PPh2), 6.94-7.12
(m, 12H, m, p-PPh2, m, p-Dip), 3.73 (sept, |J H-H| ) 7 Hz, 2H,
2
CH), 3.58 (sept, |J H-H| ) 7 Hz, 2H, CH), 3.27(d, | J P-H| ) 19
4
Hz, 1H, CHP), 1.73 (d, | J P-H| ) 2 Hz, 3H, Me), 1.38 (d, |J H-H
|
) 7 Hz, 6H, i-Pr), 1.28 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 1.13 (d,
|J H-H| ) 7 Hz, 6H, i-Pr), 0.25 (d, |J H-H| ) 7 Hz, 6H, i-Pr), -0.24
(s, AlMe, 6H); 13C{1H} NMR 173.8 (NC), 148.5 (d, |J P-C| ) 5
Hz), 145.8, 143.3, 137.9 (d, |J P-C| ) 9 Hz) 134.2 (d, |J P-C| ) 10
Hz), 132.2, 131.6, 130.9, 127.7-128.3 (m, obscured by C6D6),
126.3, 125.9, 124.8, 124.2, 64.4 (d, |J P-C| ) 129 Hz), 30.2, 28.8,
2
|J P-C| ) 113 Hz), 52.5, 30.4, 29.6, 29.3, 25.5, 24.9 (d, | J P-C| )
16 Hz), 24.5, 23.1, 21.6; 31P{1H} NMR (C6D5Cl) 31.0; 11B{1H}
3
NMR (C6D5Cl) -16.4; 19F{1H} NMR (C6D5Cl) 132.2 (d, | J F-F
|
3
3
) 6 Hz), -163.0 (d of d, | J F-F| ) 20 Hz), -166.8 (d of d, | J F-F
|
28.4, 26.2 (d, | J P-C| ) 16 Hz), 25.7, 25.1, 14.2, -6.9; 31P{1H}
2
) 17 Hz). 6: 1H NMR (C6D5Cl) 7.15-7.55 (m, 16H, o-, m-,
p-PPh2, m-, p-Dip), 4.38 (d, |J P-H| ) 21 Hz, 1H, CHP), 3.22
(sept, |J H-H| ) 7 Hz, 2H, CH), 2.95 (sept, |J H-H| ) 7 Hz, 2H,
CH), 1.84 (s, 3H, Me), 1.40 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 1.29
NMR 24.2. Anal. Calcd for C41H54AlN2P: C, 77.81; H, 8.60; N,
4.43. Found: C: 77.22; H, 8.98; N, 4.40 3: yield 85%; 1H NMR
7.67-7.74 (m, 4H, o-PPh2), 7.15-7.25 (m, 12H, m, p-PPh2, m,
p-Dip), 3.82 (sept, |J H-H| ) 7 Hz, 2H, CH), 3.70 (sept, |J H-H| )
(d, |J H-H
| ) 7 Hz, 6H, i-Pr), 1.03 (d, |J H-H| ) 7 Hz, 6H, i-Pr),
2
0.49(d, |J H-H| ) 7 Hz, 6H, i-Pr), -0.08 (s, 3H, GaMe); 31P{1H}
NMR (C6D5Cl) 32.1; 13C{1H} NMR (C6D5Cl) 169.7, 150.6 (br),
149.3, 147.3 (br), 146.2 (d, |J P-C| ) 4 Hz), 144.6, 140.3 (br),
138.4 (br), 135.4, 135.2 (br), 134.4, 132.3 (d, |J P-C| ) 10 Hz),
127.9-129.6 (m, obscured by C6D5Cl), 125.6-126.3 (m, ob-
7 Hz, 2H, CH), 3.32 (d, | J P-H| ) 19 Hz, 1H, CHP), 1.89 (d,
4
| J P-H| ) 2 Hz, 3H, Me), 1.45 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 1.40
(d, |J H-H| ) 7 Hz, 6H, i-Pr), 1.22 (d, |J H-H| ) 7 Hz, 6H, i-Pr),
0.44 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 0.16 (s, GaMe, 6H); 13C{1H}
NMR 173.0 (NC), 148.5 (d, |J P-C| ) 6 Hz), 145.6, 144.1, 139.1
(d, |J P-C| ) 9 Hz), 133.9 (d, |J P-C| ) 9 Hz), 133.3, 131.2, 127.7-
128.3 (m, obscured by C6D6), 126.1, 125.4, 124.6, 124.1, 62.9
1
scured by C6D5Cl), 125.3, 124.9, 124.5, 71.4 (d, | J P-C ) 115
2
Hz, PCH), 52.7, 30.5, 29.6, 29.0, 25.4, 25.1 (d, | J P-C| ) 16 Hz),
1
2
24.5, 23.2, 22.1, 21.7; 11B{1H} NMR (C6D5Cl) -16.5; 19F{1H}
(d, | J P-C| ) 134 Hz), 28.6, 28.3, 27.8, 26.2 (d, | J P-C| ) 16 Hz),
25.6, 25.0, 22.2, -4.7; 31P{1H} NMR 22.8. Anal. Calcd for
3
NMR (C6D5Cl) -132.1 (s), -163.0 (d of d, | J F-F| ) 21 Hz),
-166.8 (s). 8: 1H NMR (C6D5Cl) 7.07-7.42 (m, 16H, o-, m-,
C
41H54GaN2P: C, 72.89; H, 8.06; N, 4.15. Found: C, 72.46; H,
8.09; N, 4.11. 4: 337 mg, colorless needles; yield 60%; 1H NMR
(major isomer) 7.55-7.61 (m, 4H, o-PPh2), 6.70-7.29 (m, 12H,
2
p-PPh2, m-, p-Dip), 4.32 (d, | J P-H| ) 21 Hz, 1H, CHP), 3.12
(sept, |J H-H| ) 7 Hz, 2H, CH), 2.80 (sept, |J H-H| ) 7 Hz, 2H,
CH), 1.72 (s, 3H, Me), 1.29 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 1.23 (s,
m, p-PPh2, m, p-Dip), 4.59 (vbr s, 2H, AlH), 3.78 (sept, |J H-H
|
) 7 Hz, 2H, CH), 3.65 (sept, |J H-H| ) 7 Hz, 2H, CH), 3.44 (d,
3H, AlMeB), 1.32 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 0.96 (d, |J H-H
|
2
4
| J P-H| ) 22 Hz, 1H, CHP), 1.69 (d, | J P-H| ) 1 Hz, 3H, Me),
1.47 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 1.28 (d, |J H-H| ) 7 Hz, 6H,
i-Pr), 1.26 (d, J H-H| ) 7 Hz, 6H, i-Pr), 0.37 (d, |J H-H| ) 7 Hz,
6H, i-Pr); 13C{1H} NMR (major isomer) 171.3 (NC), 148.7 (d,
|J P-C| ) 5 Hz), 147.0, 141.7, 133.9 (d, |J P-C| ) 9 Hz), 132.1,
131.1, 130.9, 127.7-129.1 (m, obscured by C6D6), 127.3, 126.6,
124.8, 124.4, 63.7 (d, |J P-C| ) 127 Hz), 29.5, 28.9, 27.7, 26.3
) 7 Hz, 6H, i-Pr), 0.35 (d, |J H-H| ) 7 Hz, 6H, i-Pr), -0.73 (s,
3H, AlMe); 13C{1H} NMR (C6D5Cl) 169.9 (NC), 150.2 (br), 148.2
(br), 146.5, 145.1, 138.9 (br), 137.8 (br), 136.9 (br), 135.8 (br),
135.0, 134.4, 132.4 (d, |J P-C| ) 9 Hz), 129.0-129.5 (m, obscured
by C6D5Cl), 128.0-128.5 (m, obscured by C6D5Cl), 125.8-126.3
(m, obscured by C6D5Cl), 125.4, 124.9, 124.1, 71.4 (d, |J P-C| )
2
114 Hz), 29.6, 29.3, 25.6, 25.0 (d, | J P-C| ) 17 Hz), 23.2, 21.7,
2
(d, | J P-C| ) 17 Hz), 26.3 (s), 25.2, 22.9; 31P{1H} NMR 30.0
-14.2 (vbr); 31P{1H} NMR (C6D5Cl) 31.4; 11B{1H} NMR
(C6D5Cl) -14.6; 19F{1H} NMR (C6D5Cl) -132.2 (d, | J F-F| )
3
(major isomer), 24.3 (minor isomer); IR (KBr pellet) 1828 (asym
Al-H), 1770 (sym Al-H) cm-1. Anal. Calcd for C39H50AlN2P:
C, 77.45; H, 8.33; N, 4.63. Found: 76.95; H, 8.64; N, 4.65.
3
3
22 Hz), -164.9 (d of d, | J F-F| ) 21 Hz), -167.3 (d of d, | J F-F
|
) 21 Hz). 9: 1H NMR (C6D5Cl) 7.18-7.46 (m, 16H, o-, m-,
2
Syn th esis of (i-P r 2C6H3N)C(Me)CHP P h 2(NC6H3-i-P r 2)-
AlD2 (4d ). To a suspension of LiAlD4 (9 mg, 0.214 mmol) in 5
mL of diethyl ether cooled to -30 °C was added AlCl3 (27 mg,
0.202 mmol) in 5 mL of diethyl ether cooled to the same
temperature. The mixture was placed in the freezer and
periodically shaken over a 10 min period. The gray LiAlD4 was
slowly replaced with a white precipitate of LiCl. To this
suspension was added 1 (100 mg, 0.173 mmol) in 5 mL of
diethyl ether, and the mixture was warmed to 25 °C overnight
with stirring. The mixture was filtered through Celite and
diethyl ether removed from the filtrate under vacuum. The
resulting white powder was dissolved in 10 mL of hot n-
heptane and filtered through Celite to remove any remaining
LiAlD4. Cooling of the solution overnight gave 63 mg of
colorless needles (yield 60%). 2D NMR (toluene): 4.55 (br s,
Al-D). IR (KBr pellet): 1324 (asym Al-D), 1286 (sym Al-D)
p-PPh2, m-, p-Dip), 4.31 (d, | J P-H| ) 20 Hz, 1H, CHP), 3.12
(sept, |J H-H| ) 7 Hz, 2H, CH), 2.85 (sept, |J H-H| ) 7 Hz, 2H,
CH), 1.76 (s, 3H, Me), 1.30 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 1.25
(br s, 3H, GaMeB), 1.20 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 0.94 (d,
|J H-H| ) 7 Hz, 6H, i-Pr), 0.39 (d, |J H-H| ) 7 Hz, 6H, i-Pr), -0.14
(s, 3H, GaMe); 13C{1H} NMR (C6D5Cl) 169.6, 150.8 (br), 147.5
(br), 146.2 (d, |J P-C| ) 4 Hz), 144.6, 138.4 (m), 136.8, 135.3,
134.4, 134.1, 132.3 (d, |J P-C| ) 10 Hz), 127.9-129.6 (m,
obscured by C6D5Cl), 125.6-126.3 (m, obscured by C6D5Cl),
1
125.3, 124.9, 124.5, 70.9 (d, | J P-C| ) 114 Hz, P-C-H), 29.3,
2
28.9, 25.4, 25.1 (d, | J P-C| ) 16 Hz), 24.5, 23.1, 21.7, -9.1;
31P{1H} NMR (C6D5Cl) 32.1; 11B{1H} NMR (C6D5Cl) -14.7;
19F{1H} NMR (C6D5Cl) -132.1 (d, | J F-F| ) 20 Hz), -164.9 (d
3
of d, | J F-F| ) 21 Hz), -167.3 (d of d, | J F-F| ) 17 Hz). 11: 1H
3
3
NMR (C6D5Cl) 7.30-7.55 (m, 16H, o-, m-, p-PPh2, m-, p-Dip),
2
4.77 (d, | J P-H| ) 22 Hz, 1H, CHP), 4.42 (vbr s, 1H, AlH), 3.96
cm-1
.
(vbr s, 1H, AlH), 3.12 (sept, |J H-H| ) 7 Hz, 2H, CH), 2.80 (sept,
|J H-H| ) 7 Hz, 2H, CH), 1.80 (s, 3H, Me), 1.17 (d, |J H-H| ) 7
Gen er a t ion of [(i-P r 2C6H 3N)C(Me)CH P P h 2(NC6H 3-i-
P r 2)MMe][B(C6F 5)4] (M ) Al (5), Ga (6)), [(i-P r 2C6H3N)C-
(Me)CHP P h 2(NC6H3-i-P r 2)MMe][B(C6F 5)3Me] (M ) Al (8),
Ga (9)), a n d [(i-P r 2C6H3N)C(Me)CHP P h 2(NC6H3i-P r 2)AlH]-
[B(C6F 5)3H] (11). These compounds were prepared in a similar
fashion, and thus only one preparation is detailed. In a NMR
Hz, 6H, i-Pr), 1.12 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 0.96 (d, |J H-H
|
1
) 7 Hz, 6H, i-Pr), 0.82 (d, |J H-H| ) 7 Hz, 6H, i-Pr); H NMR
(C6D5Cl, -40 °C) 7.13-7.57 (m, 16H, o-, m-, p-PPh2, m-, p-Dip),
2
4.76 (d, | J P-H| ) 23 Hz, 1H, CHP), 4.75 (vbr s, 1H, AlH), 3.89
(vbr s, 1H, AlH), 3.17 (br s, |J H-H| ) 7 Hz, 2H, CH), 2.66 (br

Complexes of a Phosphinimine-Amide Ligand
Organometallics, Vol. 23, No. 8, 2004 1821
Ta ble 1. Cr ysta llogr a p h ic Da ta a
s, |J H-H| ) 7 Hz, 2H, CH), 1.74 (s, 3H, Me), 1.27 (br s, |J H-H
|
) 7 Hz, 6H, i-Pr), 1.11 (br s, |J H-H| ) 7 Hz, 6H, i-Pr), 0.96 (br
s, |J H-H| ) 7 Hz, 6H, i-Pr), 0.90 (br s, |J H-H| ) 7 Hz, 6H, i-Pr);
13C{1H} NMR (C6D5Cl) 172.0, 149.7 (br m), 147.8 (br m), 146.4,
1
2
4
7
formula
C
39H49NP
C41H54Al-
N2P
C
39H50Al-
N2P
C
68H61AlB-
20N2OP
2741.90
triclinic
P1h
F
146.0, 137.8 (br m), 136.1, 135.4 (br m), 134.3, 132.6 (d, |J P-C
|
formula wt
cryst syst
space group
a (Å)
b (Å)
c (Å)
576.77
632.81
604.76
) 10 Hz), 127.9-129.6 (m, obscured by C6D5Cl), 125.6-126.3
monoclinic monoclinic triclinic
P21/c P21/c P1h
27.101(19) 17.971(9) 11.103(6) 18.464(10)
9.163(6) 13.291(7) 12.961(6) 19.653(11)
19.489(14) 17.687(8) 13.665(7) 20.277(11)
89.040(10) 85.584(11)
133.634(10) 115.228(9) 70.897(9) 68.372(11)
86.943(9) 85.154(12)
1
(m, obscured by C6D5Cl), 125.4, 125.2, 124.2, 75.6 (d, | J P-C
|
2
) 109 Hz, P-C-H), 29.8, 28.6, 25.8, 25.1, 24.7 (d, | J P-C| )
16 Hz), 24.4, 24.0, 22.4; 31P{1H} NMR (C6D5Cl) 30.7; 11B{1H}
NMR (C6D5Cl) -23.6 (br); 19F{1H} NMR (C6D5Cl) -132.6 (br
s), -163.8 (vbr s), -166.4 (br s).
R (deg)
â (deg)
Syn th esis of [(i-P r 2C6H3N)C(Me)CHP P h 2(NC6H3-i-P r 2)-
AlH][B(C6F 5)4] (10). To a solution of 4 (0.183 g, 0.303 mmol)
in 3 mL of toluene was slowly added [Ph3C][B(C6F5)4] (0.279
g). Over time the orange solution turned colorless with the
precipitation of a faint yellow oil. After the mixture was stirred
overnight, 15 mL of n-pentane was added and the reaction vial
was vigorously shaken. After several minutes a white powder
separated and the mixture was stirred overnight. The sol-
vent was then decanted, and the solids were washed 3 × 10
γ (deg)
V (Å3)
3503(4)
4
3822(3)
4
1855.5(16) 6807(6)
2
Z
4
d(calcd),
1.094
1.100
1.082
1.338
g cm-3
abs coeff,
µ, cm-1
no. of data
collected
no. of data,
0.106
14322
5059
0.124
15904
5404
0.125
7974
5295
0.151
29324
19333
1
mL of n-pentane and dried to give 10 in 96% yield. H NMR
2
2
Fo > 3σ(Fo
no. of variables 379
)
(C6D5Cl): 7.09-7.53 (m, 16H, o-, m-, p-PPh2, m-, p-Dip), 4.74
406
396
1693
2
(d, | J P-H| ) 22 Hz, 1H, CHP), ∼3.95 (vbr s, 1H, AlH), 3.13
Rb
Rw
0.0533
0.0839
0.882
0.0451
0.1016
0.915
0.0410
0.1045
0.915
0.0537
0.1282
0.705
(sept, |J H-H| ) 7 Hz, 2H, CH), 2.79 (sept, |J H-H| ) 7 Hz, 2H,
CH), 1.79 (s, 3H, Me), 1.19 (d, |J H-H| ) 7 Hz, 6H, i-Pr), 1.12
(d, |J H-H| ) 7 Hz, 6H, i-Pr), 0.96 (d, |J H-H| ) 7 Hz, 6H, i-Pr),
0.85 (d, |J H-H| ) 7 Hz, 6H, i-Pr). 31P{1H} NMR (C6D5Cl): 30.6.
13C{1H} NMR (C6D5Cl): 172.1, 150.4 (br), 147.2 (br), 146.5 (d,
4 Hz), 146.1, 140.2 (br), 138.4, 137.0 (br), 136.1, 135.1, 134.4,
132.6 (d, |J P-C| ) 10 Hz), 127.9-129.6 (m, obscured by
C6D5Cl), 125.1-126.3 (m, obscured by C6D5Cl), 124.0, 122.1,
c
GOF
a
All data collected at 24 °C with Mo KR radiation (λ ) 0.710 69
Å), b R ) ∑||Fo| - |Fc||/∑|Fo|. c Rw ) [∑[w(Fo2 - Fc2)2]/∑[w(Fo2)2]]0.5
.
1
75.5 (d, | J P-C| ) 109 Hz, P-C-H), 34.3, 29.8, 28.4, 25.9, 25.1,
2
24.6 (d, | J P-C| ) 16 Hz), 24.5, 24.1, 22.6, 14.1. 11B{1H} NMR
(C6D5Cl): -20.1. 19F{1H} NMR (C6D5Cl): -132.2 (s), -163.8
3
(d of d, | J F-F| ) 21 Hz), -166.8 (s). IR (KBr pellet): 1644 (AlH)
cm-1. Anal. Calcd for C63H49AlN2PBF20: C, 58.99; H, 3.85; N,
2.18. Found: C, 58.87; H, 4.35; N, 2.01.
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 30 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 sig-
nificant 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 redun-
dant data was applied to each data set. Subsequent solution
and refinement 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.13 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. 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 not refined unless otherwise
F igu r e 1. ORTEP drawings of 1 (30% thermal ellipsoids
are shown). Hydrogen atoms are omitted for clarity.
Selected distances (Å): P(1)-N(1) ) 1.590(3), P(1)-C(25)
)
1.738(3), N(2)-C(26)
) 1.382(4), C(25)-C(26) )
1.363(4).
noted. The locations of the largest peaks in the final difference
Fourier map calculation as well as the magnitudes of the
residual electron densities in each case were of no chemical
significance. Addition details are provided in the Supporting
Information. Crystallographic data for 1, 2, 4, and 7 are given
in Table 1.
Resu lts a n d Discu ssion
Neu tr a l Com p lexes. The synthesis of the ligand 1
has been previously described.10 Crystallographic char-
acterization of 1 (Figure 1) confirmed the phosphin-
imine-amine nature. Ligand 1 reacts with MR3 (M )

1822 Organometallics, Vol. 23, No. 8, 2004
Masuda et al.
Sch em e 1
Sch em e 2
Al, Ga; R ) Me, H) with loss of RH to form the
complexes (i-Pr2C6H3N)C(Me)CHPPh2(NC6H3-i-Pr2)-
MMe2 (M ) Al (2), Ga (3)) and (i-Pr2C6H3N)C(Me)-
CHPPh2(NC6H3-i-Pr2)AlH2 (4) in approximately 60%
F igu r e 2. ORTEP drawings of 2 (30% thermal ellipsoids
are shown). Hydrogen atoms are omitted for clarity.
Selected distances (Å) and angles (deg): Al(1)-N(1) )
1.932(2), Al(1)-N(2) ) 1.943(2), Al(1)-C(40) ) 1.962(3),
Al(1)-C(41) ) 1.991(3), N(1)-C(38) ) 1.353(3), N(2)-P(1)
) 1.633(2), P(1)-C(39) ) 1.741(3), C(38)-C(39) ) 1.383-
(4); N(1)-Al(1)-N(2) ) 101.22(10), N(1)-Al(1)-C(40) )
110.36(13), N(2)-Al(1)-C(40) ) 111.57(12), N(1)-Al(1)-
C(41) ) 107.23(12), N(2)-Al(1)-C(41) ) 110.84(12), C(40)-
Al(1)-C(41) ) 114.69(15), C(38)-N(1)-Al(1) ) 116.72(18),
P(1)-N(2)-Al(1) ) 115.91(11), N(2)-P(1)-C(39) ) 109.19-
(12), N(1)-C(38)-C(39) ) 123.5(2), C(38)-C(39)-P(1) )
130.4(2).
1
isolated yields (Scheme 1). H, 13C, and 31P NMR data
confirmed the formulations, and recrystallization from
boiling n-heptane gave colorless crystalline blocks in the
case of 2 and 4. The NMR data of 2 and 3 showed metal-
bound methyl resonances at -0.24 and 0.16 ppm,
slightly upfield from the corresponding resonances for
the â-diketimine complex (NacNac)MMe2 (M ) Al,
-0.86 ppm;3 M ) Ga, -0.18 ppm14). In the case of 4,
the NMR data are consistent with the presence of two
isomers in solution in a ratio of 3.5:1. This suggests the
presence of six- and four-membered chelate rings with
Al (Scheme 2). We have reported a similar observation
for related Ni(II) and Pd(II) systems.10 The 1H NMR
resonance derived from the methine proton of the ligand
backbone in the minor isomer is a doublet of triplets
arising from coupling to P (2J P-H ) 10 Hz) and the Al-
bound hydrides (3J H-H ) 14 Hz), consistent with the
four-membered chelate form. The corresponding reso-
nance for the major isomer does not show the latter
coupling. Infrared spectroscopy shows the Al-H absorp-
tions at 1828 and 1770 cm-1, similar to those reported
for (NacNac)AlH2 (1832 and 1795 cm-1).8 Synthesis of
4d confirmed these assignments and revealed Al-D
absorptions at 1324 and 1286 cm-1 and showed a 2D
NMR resonance at 4.55 ppm. Efforts to acquire 27Al
NMR spectra for 2 and 4 were unsuccessful.11
Crystallographic studies of 2 (Figure 2) and the major
isomer of 4 (Figure 3) confirmed pseudo-tetrahedral
geometries about Al and a boat conformation of the six-
membered chelate ring. The boat conformation of 2
results in an angle of 38.6° between the mean planes
through AlN2 and C2P atoms of the chelate ring. This
puckering results in an approach of the Al atom and
C(39) at 3.087 Å. This chelated geometry stands in
contrast to that seen in 4, where the corresponding
angle and distance are 10.3° and 3.304 Å, respectively.
In an alternative description of 4, the maximum devia-
tion of the atoms of the chelate from the mean AlN2-
PC2 plane is only 0.17 Å. For 2, the Al-N bond distances
were found to be 1.932(2) and 1.943(2) Å, similar to
those seen in the analogous NacNac complex (1.920(2)
F igu r e 3. ORTEP drawings of 4 (30% thermal ellipsoids
are shown). Hydrogen atoms are omitted for clarity.
Selected distances (Å) and angles (deg): Al(1)-N(2) )
1.893(2), Al(1)-N(1) ) 1.906(2), Al(1)-H(1) ) 1.529(18),
Al(1)-H(2) ) 1.60(2), P(1)-N(1) ) 1.6253(18), P(1)-C(25)
) 1.746(2), N(2)-C(26) ) 1.370(3); N(2)-Al(1)-N(1) )
102.10(8), N(2)-Al(1)-H(1) ) 113.6(7), N(1)-Al(1)-H(1)
) 108.7(7), N(2)-Al(1)-H(2) ) 109.8(7), N(1)-Al(1)-H(2)
) 110.0(7), H(1)-Al(1)-H(2) ) 112.1(10), N(1)-P(1)-C(25)
) 108.64(10), P(1)-N(1)-Al(1) ) 121.65(10), C(26)-N(2)-
Al(1) ) 127.27(15), N(2)-C(26)-C(25) ) 123.8(2).
and 1.942(2) Å).2 The imine N-C bond is (1.353(3) Å)
slightly longer than those seen in (NacNac)AlMe2
(1.344(2) and 1.339(2) Å). Similarly, the adjacent C-C
bond (C(38)-C(39) ) 1.383(4) Å) is shorter than the
corresponding distances (1.394(3), 1.407(3) Å) seen in
(NacNac)AlMe2, while the N-Al-N bite angle in 2 of
(13) Cromer, D. T.; Mann, J . B. Acta Crystallogr., Sect. A 1968, A24,
321-324.
(14) Stender, M.; Eichler, B. E.; Hardman, N. J .; Power, P. P.; Prust,
J .; Noltemeyer, M.; Roesky, H. W. Inorg. Chem. 2001, 40, 2794-2799.

Complexes of a Phosphinimine-Amide Ligand
Organometallics, Vol. 23, No. 8, 2004 1823
Sch em e 3
101.11(10)° is larger than that (96.17(7)°) in (NacNac)-
AlMe2. These data are consistent with a more localized
charge distribution over the C-C-N fragment in the
phosphinimine-amide ligand complex. In the case of 4,
location and refinement of the H atom positions revealed
Al-H distances of 1.529(18) and 1.60(2) Å, which is in
the range seen for other Al-hydride derivatives.15
Although Al-N distances in 4 (1.906(2), 1.893(2) Å), are
shorter than those in 2, as expected, the N-Al-N bite
angle of 102.10(8)° is similar to that seen for 2.
F igu r e 4. ORTEP drawing of the cation of 7 (one of the
two in the asymmetric unit; 30% thermal ellipsoids are
shown). Hydrogen atoms are omitted for clarity. Selected
distances (Å) and angles (deg): Al(1)-N(1) ) 1.853(4),
Al(1)-N(2) ) 1.875(4), Al(1)-C(1) ) 1.946(6), Al(1)-O(1)
) 1.998(5), P(1)-N(2) ) 1.649(4), P(1)-C(3) ) 1.751(4),
N(1)-C(2) ) 1.377(5); N(1)-Al(1)-N(2) ) 105.61(17),
N(1)-Al(1)-C(1) ) 116.3(3), N(2)-Al(1)-C(1) ) 117.0(2),
N(1)-Al(1)-O(1) ) 103.88(19), N(2)-Al(1)-O(1) ) 105.08-
(18), C(1)-Al(1)-O(1) ) 107.3(3), N(2)-P(1)-C(3) ) 107.7-
(2), C(2)-N(1)-Al(1) ) 118.5(3), P(1)-N(2)-Al(1) ) 119.1-
(2), C(3)-C(2)-N(1) ) 123.2(4), C(2)-C(3)-P(1) ) 130.6(4).
Ca tion ic Com p lexes. Reactions of 2 and 3 with
[Ph3C][B(C6F5)4] in toluene or benzene formed relatively
insoluble clathrate oils,16 but the resulting salts are
soluble in C6H5Cl. These complexes, formulated as
[(i-P r 2 C6 H 3 N )C(Me)CH P P h 2 (N C6 H 3 -i-P r 2 )MMe]-
[B(C6F5)4] (M ) Al (5), Ga (6)), exhibited downfield shifts
of the 31P NMR resonances to 31.0 and 32.1 ppm,
respectively. The 1H NMR resonances for the ligand
fragments were similar to those of the precursors. The
remaining metal-bound methyl groups give rise to
upfield-shifted resonances at -0.70 and -0.08 ppm in
5 and 6, respectively. These shifts may result from the
anisotropic shielding from coordinated C6D5Cl solvent
molecules. These signals shift slightly (0.1 ppm) but do
not broaden upon cooling to -40 °C. The corresponding
13C NMR resonances for these methyl groups are broad
at 25 °C and sharpen upon cooling to -40 °C. These
observations are likely a result of the lower symmetry
of the quadrupolar Al or Ga environment. 11B and 19F
NMR signals were as expected for the presence of the
free [B(C6F5)4] anion. In the case of 5, efforts to acquire
an 27Al NMR spectrum were unsuccessful, as no dis-
cernible signals were observed. This too is attributed
to the dissymmetry of the molecule. Similar difficulties
have been reported in the literature.17 Attempts to
isolate these compounds as analytically pure materials
were unsuccessful, as they are typically highly air-
sensitive oils.
19F NMR data are as expected for symmetric methyl-
borate anions, showing no evidence of methyl or fluorine
interactions with the cationic centers. Again, these
compounds were not isolable as analytically pure ma-
terials, due their extreme air sensitivity and oily nature.
The analogous reactions of 4 with [Ph3C][B(C6F5)4]
resulted in the formation of the species formulated as
[(i-Pr2C6H3N)C(Me)CHPPh2(NC6H3-i-Pr2)AlH][B(C6F5)4]-
(10), which was obtained as an oil that upon addition
of n-pentane and vigorous stirring afforded a white solid.
In contrast to the precursor 4, the NMR data for 10
showed only a single isomer. Coupling between the
central methine proton of the ligand and the Al-bound
hydride was not observed, in contrast to the minor
isomer of 4. Thus, 10 is proposed to be a six-membered
chelate complex. Although X-ray-quality crystals could
not be obtained, 10 was isolated as an analytically pure
solid. It is presumably the extreme bulkiness of the
ligand as well as the strong donor ability of the phos-
phinimine fragment that results in the stability of this
cation.
Similarly, reactions of 2 and 3 with B(C6F5)3 result
in methyl abstraction from Al or Ga, generating the
species [(i-Pr2C6H3N)C(Me)CHPPh2(NC6H3-i-Pr2)MMe]-
[B(C6F5)3Me] (M ) Al (8), Ga (9)). In a fashion similar
to that for 6 and 7, the 1H NMR resonances for the
metal-bound methyl groups are observed upfield of the
precursors at -0.73 and -0.14 ppm for the Al and Ga
species, respectively, while the borate-bound methyl
groups are seen at 1.23 and 1.25 ppm. 11B NMR and
In a similar fashion, reaction of 4 and B(C6F5)3 results
in the formation of [(i-Pr2C6H3N)C(Me)CHPPh2(NC6H3-
i-Pr2)AlH][B(C6F5)3H] (11) (Scheme 3). This species
exhibits two broad hydride signals at 25 °C: a peak at
3.96 ppm attributed to the Al-H signal and a peak at
4.42 ppm attributed to a hydride bridging Al and B. At
1
low temperature (-40 °C) the H NMR spectra showed
resonances at 3.89 and 4.75 ppm, attributed to the two
distinct hydrides. In addition, resonances at 2.67 and
3.17 ppm were attributed to the inequivalent isopropyl
protons. Each of these sets of resonances are observed
to broaden with increasing temperature, suggesting the
(15) Twamley, B.; Hardman, N. J .; Power, P. P. Acta Crystallogr.,
Sect. E 2001, E57, m227-m228.
(16) Lambert, J . B.; Zhao, Y.; Wu, H.; Tse, W. C.; Kuhlmann, B. J .
Am. Chem. Soc. 1999, 121, 5001-5008.
(17) Korolev, A. V.; Ihara, E.; Guzei, I. A.; Young, V. G., J r.; J ordan,
R. F. J . Am. Chem. Soc. 2001, 123, 8291-8309.

1824 Organometallics, Vol. 23, No. 8, 2004
Masuda et al.
possibility of hydride exchange between the cation and
anion. However, variable-temperature H NMR experi-
Con clu sion s
1
The phosphinimine-amine ligand described herein
readily affords neutral group 13 alkyl and hydride
complexes. Subsequent reaction with a Lewis acid
results in conversion to a monomeric cation by abstrac-
tion of hydride or methyl groups. The steric bulk and
strong donor ability of this ligand allowed the isolation
of monometallic Al cations. Attempts to utilize this and
related ligands for the stabilization of reduced low-
coordinate main-group and transition-metal complexes
are the subject of current efforts.
ments suggest coalescence well above 70 °C. Conse-
quently, thermodynamic exchange parameters could not
be determined.
Attempts to grow single crystals of any of the above
base-free cations were uniformally unsuccessful; how-
ever, attempts to crystallize 5 from C6H5Cl/n-pentane/
diethyl ether solution after several weeks afforded a few
crystals of [(i-Pr2C6H3N)C(Me)CHPPh2(NC6H3-i-Pr2)-
AlMe(OEt2)][B(C6F5)4] (7). A crystallographic study of
7 (Figure 4) confirmed the formulation and, in particu-
lar, the monomeric nature of the cation. The geometry
about the Al center of the cation of 7 is pseudo-
tetrahedral, while the chelate ring is puckered, adopting
a boat conformation. The angle between the AlN2 and
PC2 planes of the chelate is 49.6°, which places Al and
C(3) 3.094 Å apart. The Al-C (1.946(6) Å) and Al-N
distances (1.853(4) and 1.875(4) Å) are shorter than
those in 5, as expected for a cation. The Al-O bond for
the coordinated diethyl ether was found to be 1.998(5)
Å. This is longer than that seen in [(CH(CPh(NSiMe3))2-
AlMe(OEt2)][B(C6F5)4]18 (1.987 Å), presumably a result
of the increased donor ability and steric bulk of the
phosphinimine-based ligand.
Ack n ow led gm en t . Financial support from the
NSERC of Canada (Discovery Grant), NOVA Chemicals
Corp., and the ORDCF is gratefully acknowledged.
J .D.M. is grateful for the award of an OGS scholarship.
Su p p or tin g In for m a tion Ava ila ble: Crystallographic
1
data in CIF format and figures giving H NMR spectra for 5,
6, 8, 9 and 11. This material is available free of charge via
the Internet at http://pubs.acs.org.
OM0306776
(18) Cosledan, F.; Hitchcock, P. B.; Lappert, M. F. Chem. Commun.
1999, 705-706.