Metallated triphenylphosphinimine complexes

Article abstract of DOI:10.1039/b305877h

The reagent [(o-C₆H₄PPh₂NSiMe₃)Li]₂ ·Et₂O 1 reacted with BCl₃ affording (o-C₆H₄PPh₂NSiMe₃)BCl₂ 4. Similarly reaction of 1 with Me₂AlCl resulted in a 1:1 mixture of (o-C₆H₄PPh₂NSiMe₃)AlMe₂ 5 and (o-C₆H₄PPh₂NSiMe₃)-Al(Me)Cl 6 while the analogous reaction of 1 with GaCl₃ gave (o-C₆H₄PPh₂NSiMe₃)₂ Ga(o-C₆H₄PPh₂NH) 7. The analogous compound [Li(o-C₆H₄PPh₂NPh)]₂· Et₂O 2 was used to make (o-C₆H₄PPh₂NPh)GaCl₂ 8, while reaction of 2 with Me₂AlCl gave a mixture of [(o-C₆H₄PPh₂NPh)AlCl₂] 9 and the salt [(o-C₆H₄PPh₂NPh)₂Al] [AlMeCl₃] 10. The compound 2 also reacts with PdCl₂(COD) affording [Pd(o-C₆H₄PPh₂NPh) (μ-Cl)]₂ 11 and [Pd(o-C₆H₄PPh₂ NPh)₂] 12. Similarly, the complexes [Ni(o-C₆H₄ PPh₂NPh)₂] 13 and [Ni(o-C₆H₄PPh₂N(3,5-C₆H₃ Me₂))₂] 14 were prepared. The compounds 4-14 have been structurally characterized by X-ray methods.

Full text of DOI:10.1039/b305877h

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Metallated triphenylphosphinimine complexes
Pingrong Wei, Katie T. K. Chan and Douglas W. Stephan*
Department of Chemistry & Biochemistry, University of Windsor, Windsor, Ontario, Canada
N9B3P4. E-mail: stephan@uwindsor.ca
Received 27th May 2003, Accepted 8th August 2003
First published as an Advance Article on the web 1st September 2003
The reagent [(o-C6H4PPh2NSiMe3)Li]2ؒEt2O 1 reacted with BCl3 affording (o-C6H4PPh2NSiMe3)BCl2 4. Similarly
reaction of 1 with Me2AlCl resulted in a 1 : 1 mixture of (o-C6H4PPh2NSiMe3)AlMe2 5 and (o-C6H4PPh2NSiMe3)-
Al(Me)Cl 6 while the analogous reaction of 1 with GaCl3 gave (o-C6H4PPh2NSiMe3)2Ga(o-C6H4PPh2NH) 7. The
analogous compound [Li(o-C6H4PPh2NPh)]2ؒEt2O 2 was used to make (o-C6H4PPh2NPh)GaCl2 8, while reaction
of 2 with Me2AlCl gave a mixture of [(o-C6H4PPh2NPh)AlCl2 9 and the salt [(o-C6H4PPh2NPh)2Al][AlMeCl3] 10.
The compound 2 also reacts with PdCl2(COD) affording [Pd(o-C6H4PPh2NPh)(µ-Cl)]2 11 and [Pd(o-C6H4PPh2NPh)2]
12. Similarly, the complexes [Ni(o-C6H4PPh2NPh)2] 13 and [Ni(o-C6H4PPh2N(3,5-C6H3Me2))2] 14 were prepared.
The compounds 4–14 have been structurally characterized by X-ray methods.
Synthesis of (o-C6H4PPh2NSiMe3)BCl2 4. To a stirred solu-
tion of BCl3 (1.0 M, 0.163 mL, 0.163 mmol) in toluene (10 mL)
was added 1 (0.064 g, 0.082 mmol) in toluene (5 mL). The
resulting solution was stirred overnight at 25 ЊC and filtered
Introduction
The current interest in diimine ligands and the use of related
late transition metal complexes in olefin polymerization
catalysis1–14 has prompted our efforts to probe the coordination
through Celite. Colorless crystals were isolated upon the evap-
and organometallic chemistry of related phosphinimide and
phosphinimine based ligand complexes. While our efforts in the
oration of solvent. Yield 0.030 g, 43%. 31P{1H} NMR δ: 46.5
1
(s). 31P{1H} NMR δ: 47.12 (s). H NMR δ: 8.31–8.28 (br, 1H,
chemistry of early transition metal phosphinimides have
Ph), 7.64–7.57(br, 4H, Ph), 7.19 (br, 1H, Ph), 6.98–6.77 (br, 8H,
resulted in the development of new commercially viable olefin
Ph), 0.37 (s, 9H, SiMe3). 13C{1H} NMR δ: 133.9 (br, Ph), 133.8
polymerization catalysts,15,16 our studies in related late metal
(s, Ph), 132.2 (s, Ph), 132.0 (s, Ph), 129.6 (s, Ph), 129.5 (s, Ph),
phosphinimine systems are just beginning to appear. In recent
126.9 (s, Ph), 126.0 (s, Ph), 125.8 (s, Ph), 125.6 (s, Ph), 3.4 (s,
work we have described the development of phosphinimine-
SiMe3). Anal. Calcd. (found) for C21H23NPSiBCl2: C, 58.63
pyridine and phosphinimine-imidazole chelate complexes of Fe
(59.19); H, 5.39 (5.60); N, 3.26 (3.33%).
and Ni.17 In recent papers, Stalke and co-workers have also
described Sn, Pb18 and Zn19 complexes of the ortho-metallated
Synthesis of (o-C6H4PPh2NSiMe3)AlMe2 5 and (o-C6H4PPh2-
triphenylphosphinimines. In very recent work we have
NSiMe3)Al(Me)Cl 6. To a stirred solution of Me2AlCl (1.0 M,
0.183 mL, 0.183 mmol) in toluene (10 mL) was added the
lithiated iminophosphorane 1 (0.072 g, 0.092 mmol) in toluene
(5 mL). The resulting solution was stirred overnight at 25 ЊC
and filtered through Celite. Colorless crystals of 5/6 were
obtained from toluene. Efforts to separate these products were
futile, however, these compounds co-crystallized. X-Ray
crystallography showed that these species were (o-C6H4PPh2-
described related Rh complexes as well as similar imidazolate-
phosphinimine complexes.20 Such ligand variations have been
shown to alter the course of facile oxidative addition reactions
of CH2Cl2 at Rh. In efforts to broaden the range of compounds
accessible for future study, we have explored synthetic pathways
to main group and transition metal complexes of metallated
phosphinimines. In this manuscript we describe the preparation
and structure of these species. The implications of this
chemistry are considered.
NSiMe3)AlMe2 5 and (o-C6H4PPh2NSiMe3)Al(Me)Cl 6. Yield
0.040 g, 54%. 31P{1H} NMR δ: 34.1, 33.7. 1H NMR δ: 8.05–7.99
(br, 2H, Ph), 7.70–7.44 (br, 8H, Ph), 7.28–7.20 (br, 1H, Ph),
Experimental
7.06–7.02 (br, 1H, Ph), 6.98–6.85 (br, 16H, Ph), 0.24 (s, 3H,
Me), 0.16 (s, 9H, SiMe3), 0.12 (s, 9H, SiMe3), 0.06 (s, 6H, Me).
13C{1H} NMR δ: 136.7 (d, Ph), 136.5 (s, Ph), 136.4 (s, Ph), 133.7
(s, Ph), 133.5 (s, Ph), 133.4 (s, Ph), 133.2 (s, Ph), 132.8 (d, Ph),
131.8 (d, Ph), 131.3 (s, Ph), 131.1 (d, Ph), 130.1 (s, Ph), 129.6 (s,
Ph), 129.4 (s, Ph), 129.2 (s, Ph), 129.1 (s, Ph), 127.45 (s, Ph),
127.3 (s, Ph), 3.5 (d, SiMe3), 3.4 (d, SiMe3), Ϫ5.2 (d, Me), Ϫ5.4
(d, Me). Anal. Calcd. (found) for C45H55N2P2Si2Al2Cl: C, 65.00
(64.79); H, 6.67 (6.86); N, 3.37 (3.37%).
General data
All preparations were done under an atmosphere of dry, O2-free
N2 employing both Schlenk line techniques and a Vacuum
Atmospheres inert atmosphere glove box. Solvents were puri-
fied employing a Grubbs’ type solvent purification system
manufactured 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 ЊC unless otherwise noted. Trace amounts of protonated
solvents were used as references and chemical shifts are
reported relative to SiMe4. For 31P{1H} NMR spectra they were
referenced to external 85% H3PO4. Combustion analyses were
done in-house employing a Perkin Elmer CHN Analyzer.
Ph3PNPh was purchased from the Aldrich Chemical Company.
The compounds [(o-C6H4PPh2NSiMe3)Li]2ؒEt2O 1, [(o-C6H4-
PPh2NPh)Li]2ؒEt2O 2 and [Li(o-C6H4PPh2N(3,5-C6H3Me2))2]2ؒ
Et2O 3 were prepared by reaction of the precursor phos-
phinimine with MeLi or PhLi, with minor modifications to
known methods.17,21–23
Synthesis of (o-C6H4PPh2NSiMe3)2Ga(o-C6H4PPh2NH) 7. To
a stirred solution of GaCl3 (0.025 g, 0.142 mmol) in Et2O
(10 mL) was added the lithiated iminophosphorane 1 (0.162 g,
0.206 mmol) in Et2O (5 mL). The resulting solution was stirred
overnight at room temperature. The volatiles were removed
under vacuum. Colorless crystals were obtained from toluene.
1
Yield 0.050 g, 34%. 31P{1H} NMR δ: 27.3, 20.9. H NMR δ:
7.77–7.69 (br, 12H, Ph), 7.16–7.00 (br, 30H, Ph), 0.39 (s, 18H,
SiMe3). 13C{1H} NMR δ: 137.1 (s, Ph), 135.8 (s, Ph), 134.1 (s,
Ph), 133.9 (s, Ph), 132.8 (s, Ph), 132.6 (s, Ph), 131.2 (s, Ph), 4.8
(s, SiMe3). Anal. Calcd. (found) for C60H61N3P3Si2Ga: C, 69.10
(68.65); H, 5.90 (6.59); N, 4.03 (3.66%).
D a l t o n T r a n s . , 2 0 0 3 , 3 8 0 4 – 3 8 1 0
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
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Synthesis of (o-C6H4PPh2NPh)GaCl2 8. To a stirred solution
of GaCl3 (0.022 g, 0.125 mmol) in toluene (10 mL) was added
the lithiated iminophosphorane 2 (0.054 g, 0.068 mmol) in tolu-
ene (5 mL). The resulting solution was stirred overnight at
room temperature and filtered through Celite. Colorless crystals
of 8 were obtained from a mixture of toluene/hexane. Yield
0.020 g, 32%. 31P{1H} NMR δ: 25.6. 1H NMR δ: 7.84–7.81 (br,
1H, Ph), 7.49–7.42 (br, 6H, Ph), 7.08–7.03 (br, 1H, Ph), 6.95–
6.73 (br, 11H, Ph). 13C{1H} NMR δ: 137.0 (s, Ph), 136.3 (s, Ph),
136.2 (s, Ph), 135.8 (s, Ph), 133.8 (s, Ph), 133.7 (s, Ph), 133.3 (s,
Ph), 129.8 (s, Ph), 129.6 (s, Ph), 126.6 (s, Ph), 126.5 (s, Ph), 124.4
(s, Ph). Anal. Calcd. (found) for C24H19NPGaCl2: C, 58.47
(58.20); H, 3.88 (3.92); N, 2.84 (2.90%).
similar methods and thus only one preparation is detailed. A
solution of 2 (0.13 g, 0.16 mmol) and NiBr2(PPh3)2 (0.12 g, 0.16
mmol) was dissolved in THF (5 mL) at Ϫ20 ЊC. The reddish
solution was stirred overnight at 25 ЊC, and then the solvent was
removed in vacuo. The residue was washed with pentane and
recrystallized from benzene to afford red crystals of 13. Yield:
0.17 g, 74%. 1H NMR δ: 8.02 (dd, 1H, 3JH–H = 8 Hz, P(C6H4)),
7.62 (m, 4H, 3JP–H = 11 Hz, 3JH–H = 8 Hz, PPh2), 6.98 (m, 9H),
6.86 (m, 1H, P(C6H4)), 6.74 (m, 1H, P(C6H4)), 6.67 (m, 3H,
2
NPh, P(C6H4)). 13C{1H} NMR δ: 170.4 (d, JP–C = 24 Hz,
P(C6H4Ni)(ipso-C)), 149.6 (s, P(C6H4)(ipso-C)), 143.8 (s, PPh),
143.5 (s, P(C6H4)), 141.7 (s, PPh), 133.6 (d, 2JP–C = 10 Hz, PPh2),
132.7 (s), 131.5 (s, P(C6H4)), 131.3 (s), 130.4 (s, NPh), 121.8
(s, P(C6H4)), 120.1 (s, P(C6H4)). 31P{1H} NMR δ: 33.7 (s).
Anal. Calcd. (found) for C48H38P2N2Ni: C, 75.51 (74.97); H,
5.02 (5.27); N, 3.67 (3.51%). 14: Yield : 0.08 g, 58 %. The
molecule 14 co-crystallizes with benzene and the by-product
NiBr(PPh3)3 in the following ratio NiBr(PPh3)3ؒ0.5C6H6ؒ0.514.
Synthesis of (o-C6H4PPh2NPh)AlCl2 9 and [(o-C6H4PPh2-
NPh)2Al][AlMeCl3] 10. To a stirred solution of Me2AlCl
(1.0 M, 0.125 mL, 0.125 mmol) in toluene (10 mL) was added
the lithiated iminophosphorane 2 (0.054 g, 0.068 mmol) in tolu-
ene (5 mL). The resulting solution was stirred overnight at
room temperature and filtered through Celite. A mixture of
colorless crystals of 9 and 10 were obtained from toluene/
hexane. These species were not separable except by crystal selec-
3
1H NMR δ: 8.04 (d, 2H, JH–H = 8 Hz, PC6H4), 7.74–7.62 (m,
8H, PPh2), 7.08–6.95 (m, 14H), 6.92–6.83 (m, 2H, PC6H4),
6.81–6.73 (m, 2H, PC6H4), 6.64 (s, 4H, C6H3Me2), 6.26 (s, 2H,
C6H3Me2), 1.90 (s, 12H, Me). 13C{1H}NMR δ: 169.7 (d, 2JP–C
=
1
tion. 9/10: Yield 0.02 g, 33%. 31P{1H} NMR δ: 33.4, 31.9. H
25 Hz, PC6H4), 149.5 (s, PC6H4), 144.3 (s, PPh2), 142.8 (s,
PC6H4), 141.7 (s, PPh2), 135.6 (s, PPh2), 133.3 (d, 2JP–C = 10 Hz,
PPh2), 132.0 (s), 131.4 (s, PC6H4), 129.1 (s, C6H3Me2), 126.6
NMR δ: 8.08–8.05, 7.86–7.83, 7.71–7.64, 7.39–7.25, 7.08–6.62
(br, Ph), 0.08 (s, Me). 13C{1H} NMR δ: 142.9 (d, Ph), 140.4 (d,
Ph), 137.6 (s, Ph), 137.3 (s, Ph), 134.7 (d, Ph), 133.9 (s, Ph),
133.7 (m, Ph), 133.4 (d, Ph), 130.5 (d, Ph), 130.1 (m, Ph), 129.7
(m, Ph), 126.4 (d, Ph), 124.5 (s, Ph), 123.7 (s, Ph), Ϫ7.7 (s, Me).
Anal. Calcd. (found) for C73H60N3P3Al3Cl5: C, 65.90 (65.81); H,
4.55 (5.39); N, 3.16 (2.83%).
2
(d, JP–C = 14 Hz, PC6H4), 122.4 (s), 121.7 (s, C6H3Me2),
20.9 (s, Me). 31P{1H}NMR δ: 35.4 (s). Anal. Calcd. (found)
for C52H46P2N2Ni: C, 76.20 (76.08); H, 5.66 (5.34); N, 3.42
(3.21%).
Crystallography
Synthesis of [Pd(o-C6H4PPh2NPh)(ꢀ-Cl)]2 11 and [Pd(o-C6-
H4PPh2NPh)2] 12. A solution of 2 (0.23 g, 0.28 mmol) and
PdCl2(COD) (0.08 g, 0.28 mmol) was dissolved in THF (5 mL).
The mixture was stirred at 25 ЊC for 6 h during which time a
fine grayish green solid precipitated from solution. The hetero-
geneous mixture was stirred overnight, and then filtered
through Celite and the solvent removed in vacuo. The yellow
residue was dissolved in CH2Cl2 and recrystallized to afford tiny
orange crystals of 11. Yield: 0.04 g, 14%. The yellow filtrate was
concentrated to ca. 1 mL and benzene slowly added. A yellow
powder precipitated after standing overnight. The yellow
powder was isolated by filtration and dissolved in CH2Cl2 and
cooled to Ϫ20 ЊC affording crystals of 12 Yield: 0.12 g, 52%. 11:
1H NMR(CD2Cl2) δ: 7.83–7.79 (m, 8H, PPh2), 7.61–7.59 (m,
6H, PPh2), 7.50 (m, 2H, PC6H4), 7.49–7.47 (m, 8H), 7.27 (dd,
X-Ray data collection and reduction. Crystals were manipu-
lated and mounted in capillaries in a glove box, thus maintain-
ing 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 second exposure times. The
observed extinctions were consistent with the space groups in
each case. The data sets were collected (4.5Њ<2θ<45–50.0Њ). 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.37 An empirical
absorption correction based on redundant data was applied to
each data set. Subsequent solution and refinement was per-
formed using the SHELXTL37 solution package operating on a
Pentium computer. See Table 1 for crystallographic details.
3
2H, JH–H = 8 Hz, PC6H4), 7.07–6.99 (m, 4H, NPh), 6.93–6.91
(m, 4H, NPh), 6.86 (d, 2H, 3JH–H = 7 Hz, PC6H4), 6.82–6.79 (m,
2
2H, NPh). 13C{1H} NMR(CD2Cl2) δ: 149.2 (d, JP–C = 18 Hz,
PC6H4), 147.1 (s, PC6H4), 142.2 (s, PPh2), 135.4 (s, PPh2), 133.2
(d, 2JP–C = 10 Hz, PPh2), 133.0 (s, PPh2), 129.9 (s, NPh), 127.9 (s,
NPh), 127.5 (s, PC6H4), 126.9 (s, NPh), 126.3 (d, 2JP–C = 11 Hz,
PC6H4), 125.2 (s, NPh), 124.3 (s, PC6H4), 121.5 (s, PC6H4).
31P{1H} NMR(CD2Cl2) δ: 45.5 (s). Anal. Calcd. (found) for
C48H38P2N2Cl2Pd2: C, 58.32 (57.12); H, 3.87 (3.85); N, 2.83
Structure solution and refinement. Non-hydrogen atomic scat-
tering factors were taken from the literature tabulations.24 The
heavy atom positions were determined using direct methods
employing the SHELXTL37 direct methods routine. 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| Ϫ |Fc|)2 where the weight ω is
defined as 4Fo /2σ(Fo ) 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 aniso-
tropic temperature factors in the absence of disorder or insuffi-
cient 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 calculation as well as the magnitude of the resi-
1
3
(2.64%). 12: H NMR δ: 8.27(d, 1H, JH–H = 8 Hz, P(C6H4)),
7.69 (m, 4H, 3JP–H = 11 Hz, 3JH–H = 7 Hz, PPh2(o-H)), 7.23 (m,
1H, 3JH–H = 8 Hz, P(C6H4)), 7.02 (dt, 2H, 3JH–H = 7 Hz, 4JP–H
=
1 Hz, NPh), 6.95 (dt, 4H, 3JH–H = 8 Hz, 4JP–H = 2 Hz, PPh2), 6.80
(m, 4H), 6.75–6.72 (dd, 2H, 3JH–H = 8 Hz, PPh2(p-H)), 6.62 (dd,
2
2
3
2
1H, JH–H = 7 Hz, NPh). 13C{1H} NMR δ: 171.2 (d, JP–C = 20
Hz, P(C6H4Pd)), 148.9(s, P(C6H4)(ipso-C)), 144.9 (s, PPh),
143.0 (s, PPh), 140.9 (s), 133.8 (d, 2JP–C = 10 Hz, PPh2), 131.6 (s),
131.1 (s), 130.0 (s), 129.9 (s, NPh), 127.2(s, NPh), 125.9 (d, 2JP–C
= 12 Hz, P(C6H4)), 121.9(s), 121.8 (s, P(C6H4)), 119.1 (s,
P(C6H4)). 31P{1H} NMR δ: 27.8 (s). Anal. Calcd. (found) for
C48H38P2N2Pd: C, 71.07 (70.62); H, 4.72 (4.39); N, 3.45 (3.08%).
Synthesis of [Ni(o-C6H4PPh2NPh)2] 13 and [Ni(o-C6H4PPh2N-
(3,5-C6H3Me2))2] 14. These compounds were prepared by
D a l t o n T r a n s . , 2 0 0 3 , 3 8 0 4 – 3 8 1 0
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dual electron densities in each case were of no chemical
significance.
CCDC reference numbers 211243–211251.
See http://www.rsc.org/suppdata/dt/b3/b305877h/ for crystal-
lographic data in CIF or other electronic format.
Results and discussion
The reagent [(o-C6H4PPh2NSiMe3)Li]2ؒEt2O 1 was prepared via
literature methods23 and reacted with BCl3 to give colorless
crystals of (o-C6H4PPh2NSiMe3)BCl2 4 in 43% yield (Scheme 1).
The NMR data were as anticipated and an X-ray study con-
firmed this formulation (Fig. 1). The pseudo-tetrahedral
coordination sphere about B is comprised of the aryl-C, the
phosphinimine-N and the two Cl atoms. The B–N distance is
1.576(4) Å which is much longer than the B–N seen in the
phosphinimide derivative [(t-Bu3PN)2B]Cl (1.258(5) Å)25 or
[B(NPPh3)3] (1.446(8) Å).26 The B–C bond is slightly longer at
1.597(5) Å, while the B–Cl distances average 1.893(6) Å. The
P–N distance is typical at 1.624(3) Å. The bite angle of the
anionic metallated-phosphinimine chelate is 106.1(3)Њ similar to
the Cl–B–Cl angle of 106.8(2)Њ. The B–N–P angle is 110.0(2)Њ,
typical of trigonal planar N donors.
Scheme 1
A similar reaction of 1 with Me2AlCl resulted in a 1 : 1
mixture of two products as evidenced by the31P{1H} NMR sig-
nals at 34.1 and 33.7 ppm. Efforts to separate these products
were futile, however, these compounds co-crystallized. X-Ray
crystallography showed that these species were (o-C6H4PPh2-
NSiMe3)AlMe2
5
and (o-C6H4PPh2NSiMe3)Al(Me)Cl
6
(Scheme 1). While the general geometry of these species was
similar to that observed for 4, a detailed discussion of the
metric parameters is not possible due to the disordered methyl
and chloride ligands.
The analogous reaction of 1 with GaCl3 also resulted in
colorless crystals however, 31P{1H} NMR data showed two
resonances at 27.3 and 20.9 ppm consistent with different phos-
phinimine ligands in a 2 : 1 ratio.1H NMR spectra showed only
one resonance for the SiMe3 groups. X-Ray diffraction revealed
the formulation of 7 as (o-C6H4PPh2NSiMe3)2Ga(o-C6H4PPh2-
NH) (Fig. 2, Scheme 1). In this molecule two phosphinimine
ligands 1 are bound to Ga only through the aryl-C atoms. A
third ligand chelates to the Ga center where the SiMe3 on N has
been replaced by H.
The resulting geometry about Ga is that of a distorted tetra-
hedron. The bite angle for the chelating ligand is 86.8(3)Њ con-
siderably less than that seen above in 4. The remaining angles
about Ga range from 101.0(2)Њ to 127.3(3)Њ. The average Ga–C
distance is 2.026(8) Å while the Ga–N distance is 2.007(6) Å.
The P–N distance in the chelating metallated phosphinimine
(NH) is slightly longer (1.585(6) Å) than those seen in the
pendant ligands (1.550(5) Å, 1.564(6) Å).
Clearly the replacement of SiMe3 by proton reduces the steric
congestion about Ga allowing chelation to occur. However the
source of the proton could not be identified. Nonetheless it is
perhaps a bit surprising that this metallated ligand does not
D a l t o n T r a n s . , 2 0 0 3 , 3 8 0 4 – 3 8 1 0
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The phosphinimine Ph3PNPh is commercially available and
is readily lithiated to give [Li(o-C6H4PPh2NPh)]2ؒEt2O 2 using a
method analogous to that previously reported.21 This species
reacted with GaCl3 to give a complex of formula (o-C6H4-
PPh2NPh)GaCl2 8 in moderate yields (Scheme 3). This com-
pound was also characterized crystallographically (Fig. 3). In
this case, similar disorder models were required. These models
involved 50 : 50 disorders of the P, N and M atoms. This
unusual disorder appears to arise because of the approximately
co-planar nature of the metallated-arene ring and the N-bound
phenyl group which allows the PC6H4 and PNPh to disorder.
Again, more detailed comments on the metric parameters are
precluded by this disorder.
Fig. 1 ORTEP37 drawing of 4, 30% thermal ellipsoids are shown,
hydrogen atoms have been omitted for clarity. Selected bond distances
(Å) and angles (Њ): B(1)–N(1) 1.576(4), B(1)–C(1) 1.597(5), B(1)–Cl(2)
1.877(4), B(1)–Cl(1) 1.909(4), P(1)–N(1) 1.624(3); N(1)–B(1)–C(1)
106.1(3), N(1)–B(1)–Cl(2) 111.7(3), C(1)–B(1)–Cl(2) 112.7(3), N(1)–
B(1)–Cl(1) 110.3(2), C(1)–B(1)–Cl(1) 109.3(3), Cl(2)–B(1)–Cl(1)
106.8(2), B(1)–N(1)–P(1) 110.0(2).
Scheme 3
Fig. 3 ORTEP drawing of 9, 30% thermal ellipsoids are shown,
hydrogen atoms have been omitted for clarity. Selected bond distances
(Å) and angles (Њ): 9: Al(1)–N(1) 1.944(9), Al(1)–Cl(2) 2.076(5), Al(1)–
Cl(1) 2.101(5), Al(1)–C(1) 2.133(13); N(1)–Al(1)–Cl(2) 108.5(3), N(1)–
Al(1)–Cl(1) 110.1(3), Cl(2)–Al(1)–Cl(1) 113.3(2). 8: Ga(1)–N(1)
1.636(10), Ga(1)–C(1) 2.004(9), Ga(1)–Cl(2) 2.157(2), Ga(1)–Cl(1)
2.241(2); N(1)–Ga(1)–C(1) 65.4(6), N(1)–Ga(1)–Cl(2) 125.7(4), C(1)–
Ga(1)–Cl(2) 120.3(3), N(1)–Ga(1)–Cl(1) 118.8(4), C(1)–Ga(1)–Cl(1)
112.7(3), Cl(2)–Ga(1)–Cl(1) 107.84(9).
Fig. 2 ORTEP drawing of 7, 30% thermal ellipsoids are shown,
hydrogen atoms have been omitted for clarity. Selected bond distances
(Å) and angles (Њ): Ga(1)–N(1) 2.007(6), Ga(1)–C(40) 2.019(6), Ga(1)–
C(19) 2.028(7), Ga(1)–C(18) 2.033(8), P(1)–N(1) 1.585(6), P(2)–N(2)
1.550(5), P(2)–C(24) 1.797(7), P(3)–N(3) 1.564(6), Si(1)–N(2) 1.683(6),
Si(2)–N(3) 1.680(6); N(1)–Ga(1)–C(40) 101.0(2), N(1)–Ga(1)–C(19)
102.6(3), C(40)–Ga(1)–C(19) 127.3(3), N(1)–Ga(1)–C(18) 86.8(3),
C(40)–Ga(1)–C(18) 114.2(3), C(19)–Ga(1)–C(18) 113.5(3), P(1)–N(1)–
Ga(1) 118.1(3), P(2)–N(2)–Si(1) 136.6(4), P(3)–N(3)–Si(2) 140.5(4).
Interestingly in a reaction, reminiscent of that affording 5
and 6, reaction of 2 with Me2AlCl also gave a mixture of prod-
ucts. Although the two products could not be separated by
solubility, crystal selection afforded X-ray studies. In the crystal
structure of product 9 a formulation and disorder structure
analogous to 8 confirmed the formulation as (o-C6H4PPh2-
NPh)AlCl2 9. The second species, 10 was obtained only as poor
quality crystals. X-Ray studies confirmed this material was a
salt. While the cation refined nicely, the disordered nature of
the anion could not be resolved. Thus, based on X-ray and
elemental analyses data, 10 was formulated as [(o-C6H4PPh2-
NPh)2Al][AlMeCl3]. As only the gross structural features of 10
were ascertained, the solution is not publishable.29
Scheme 2
appear to rearrange to the Ph3PNϪ tautomer (Scheme
2). A number of N-bound complexes of Ph3PNϪ have been
previously reported.27,28
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In extending the chemistry of these metallated phosphin-
imines attempts were made to react 1 with various Ni(), Pd()
or Pt() reagents under a variety of reaction conditions. In all
cases no products could be isolated. Similarly, attempts to first
brominate 1 and then effect oxidative addition to Ni(0) species
failed to give isolable arylated phosphinimine complexes. In
contrast, reaction of 2 with PdCl2(COD) in a 1 : 1 ratio in
THF afforded a low yield (14%) of a compound formulated on
the basis of NMR and EA data as [Pd(o-C6H4PPh2NPh)-
(µ-Cl)]2 11 (Scheme 4). Crystallographic data confirmed the
two-fold symmetry of this dimeric formulation (Fig. 4). The
two Pd centers are bridged by two Cl atoms. Each Pd atom
has a slightly distorted square planar coordination environ-
ment. However, the Pd–Cl distances were found to be
2.3502(12) Å and 2.5130(13) Å. This dissymmetry arises as a
result of greater trans influence of C versus the N-donor atoms.
The Pd–C distance in 11 is 1.992(2) Å while the Pd–N distance
is 2.047(2) Å with a chelate bite angle of 85.45(10)Њ. The bridg-
ing Pd–Cl–PdЈ angle is 77.46(4)Њ while the angle between Pd-
coordination planes is 83.5Њ. This results in a Pd–PdЈ separation
of 3.0453(17) Å.
Fig. 5 ORTEP drawing of 12, 30% thermal ellipsoids are shown,
hydrogen atoms have been omitted for clarity. Selected bond distances
(Å) and angles (Њ): Pd(1)–C(25) 2.004(3), Pd(1)–C(1) 2.011(3), Pd(1)–
N(1) 2.146(3), Pd(1)–N(2) 2.172(3), Pd(1)–P(2) 2.9729(19), N(1)–P(1)
1.599(3), N(2)–C(43) 1.404(5), N(2)–P(2) 1.607(3); C(25)–Pd(1)–C(1)
94.27(14), C(25)–Pd(1)–N(1) 176.57(12), C(1)–Pd(1)–N(1) 86.30(12),
C(25)–Pd(1)–N(2) 84.70(12), C(1)–Pd(1)–N(2) 176.58(12), N(1)–Pd(1)–
N(2) 94.92(11), C(25)–Pd(1)–P(2) 61.61(10), C(1)–Pd(1)–P(2)
145.22(10), N(1)–Pd(1)–P(2) 119.33(7), N(2)–Pd(1)–P(2) 31.83(8),
C(7)–N(1)–P(1) 126.1(2), C(7)–N(1)–Pd(1) 126.4(2), P(1)–N(1)–Pd(1)
105.41(15), C(43)–N(2)–P(2) 126.9(2), C(43)–N(2)–Pd(1) 127.4(2),
P(2)–N(2)–Pd(1) 102.71(15), C(6)–C(1)–Pd(1) 128.2(3), C(2)–C(1)–
Pd(1) 115.4(3), C(30)–C(25)–Pd(1) 128.9(2), C(26)–C(25)–Pd(1)
115.0(2).
Scheme 4
the bite angles of the chelates in 12 of 86.30(12)Њ and 84.70(12)Њ
are in the same range as that seen in 11.
Compound 12 was observed to be light sensitive, decompos-
ing to a black solid. While 11 is stable to light, the sensitivity of
12 suggests that reductive coupling of the aryl rings could be
photochemically induced although this was not confirmed.
This notion inferred a cis arrangement of the arene rings, a
structural feature that was subsequently confirmed by the
growth of X-ray quality crystals of 12 by recrystallization at
Ϫ20 ЊC in the dark. In a similar sense Stalke et al.19 observed
that reaction of 1 with CuCl2 resulted in the reductive coupling
product [(o-C6H4PPh2NSiMe3)2].
Using the starting material NiBr2(PPh3)2 attempts to prepare
related Ni complexes resulted only in the isolation of the Ni-
analog of 12, [Ni(o-C6H4PPh2NPh)2] 13 (Scheme 4). Using
optimized stoichiometry this species was isolated in 74% yield.
The compound was diamagnetic and the NMR data suggested
a structure similar to 12, an inference that was confirmed by
an X-ray structural study of 13 (Fig. 6). The distorted
square planar geometry about Ni is similar to that seen in 12
with Ni–C distances of 1.898(5) Å and 1.910(5) Å and Ni–N
1.982(4) Å and 2.018(3) Å respectively. The Ni–C distances
are longer than those found in [NiBr{o-C6H4B(pin)}-
(PPh3)2] (1.894(3) Å),31 [NiCl(C6H2{CH2NMe2}2-2,6-SiMe3-4)]
(1.8850(16) Å)33 and in trans-(Me3P)BrNi(η2-C(NBut)CH2-o-
C6H4)NiBr(PMe3)2 (1.90(2) Å).34 The C–Ni–N bite angles in 13
(89.98(19)Њ, 89.23(19)Њ) were found to be slightly greater than
those in 12. The average P–N bond length in 13 (1.616(4) Å), is
only slightly longer than that seen in 12 (1.604(3) Å) and the
parent phosphinimine Ph3PNPh (1.602(3) Å).35
A similar synthetic approach has also been employed to react
[Li(o-C6H4PPh2N(3,5-C6H3Me2))2]ؒEt2O 3 with NiBr2(PPh3)2.
While this reaction yields orange X-ray quality crystals, a side-
product is also obtained. Fortunately, X-ray diffraction studies
confirmed the co-crystallization of the two-fold symmetric
species [Ni(o-C6H4PPh2N(3,5-C6H3Me2))2] 14 (Fig. 7) with a
two symmetry benzene of crystallization and the by-product
NiBr(PPh3)3. The geometry of NiBr(PPh3)3 was as previously
reported.36 The structure of the latter by-product is identical to
that previously reported, while the structure of 14 is similar to
Fig. 4 ORTEP drawing of 11, 30% thermal ellipsoids are shown,
hydrogen atoms have been omitted for clarity. Atoms that are marked
with primes refer to equivalent positions (Ϫx, y, 0.5 Ϫ z). Selected bond
distances (Å) and angles (Њ): Pd(1)–C(6) 1.992(2), Pd(1)–N(1) 2.047(2),
Pd(1)–Cl(1) 2.3502(12), Pd(1)–Cl(1) 2.5130(13), Pd(1)–Pd(1)
3.0453(17), P(1)–N(1) 1.614(2); C(6)–Pd(1)–N(1) 85.45(10), C(6)–
Pd(1)–Cl(1) 96.09(8), N(1)–Pd(1)–Cl(1) 177.79(6), C(6)–Pd(1)–Cl(1)
166.98(7), N(1)–Pd(1)–Cl(1) 94.04(7), Cl(1)–Pd(1)–Cl(1) 84.81(4),
Pd(1)–Cl(1)–Pd(1) 77.46(4), C(19)–N(1)–P(1) 125.01(17), C(19)–N(1)–
Pd(1) 122.32(16), P(1)–N(1)–Pd(1) 110.84(11), C(5)–C(6)–Pd(1)
126.39(19), C(1)–C(6)–Pd(1) 116.50(18).
Attempts to improve the yield of 11 were unsuccessful. How-
ever, reaction of 2 with PdCl2(COD) afforded a product form-
ulated as [Pd(o-C6H4PPh2NPh)2] 12 in about 50% yield (Scheme
4). The upfield 31P resonance observed for 12 compared to that
of 11 was consistent with the presence of a second strong donor
ligand on Pd. The structure was confirmed crystallographically
(Fig. 5). The geometry about Pd is approximately square planar
in which the two aryl C atoms are cis to one another. The Pd–C
distances in 12 are 2.004(3) Å and 2.011(3) Å while the Pd–N
distances in 12 are 2.146(3) Å and 2.172(3) Å. Both are longer
than those seen in 11, consistent with the presence of the strong
donor ligands. The Pd–C bonds are longer than those seen in
[Pd(C6H5)Br(PMe3)CPh(NEt2)] (2.016(5) Å),30 [PdBr{o-C6-
H4B(pin)}(PCy3)2] (pin = pinacolato) (2.026(5) Å),31 and trans-
[PdCl{C6H3(CO2H)2-2,5}(PPh3)2] (2.000(3) Å).32 In contrast,
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Similar phenomena have been observed for related Sn, Pb18 and
Zn19 compounds. This is thought to be an artifact of solubility
and electronic effects. The mono-ligated species are more
soluble than the halide precursors and at the same time incor-
poration of the strong donor aryl and phosphinimine ligands
acts to labilize the remaining halides prompting further substi-
tution. Efforts to utilize these strong donor ligands and their
complexes are the subject of on-going studies.
Acknowledgements
Financial support from NSERC of Canada, NOVA Chemicals
Corporation and the ORDCF is gratefully acknowledged.
D. W. S. is grateful for the award of Forschungpreis from the
Alexander von Humboldt Stiftung.
References and notes
Fig. 6 ORTEP drawing of 13, 30% thermal ellipsoids are shown,
hydrogen atoms have been omitted for clarity. Selected bond distances
(Å) and angles (Њ): Ni(1)–C(30) 1.898(5), Ni(1)–C(1) 1.910(5), Ni(1)–
N(1) 1.982(4), Ni(1)–N(2) 2.018(3), P(1)–N(1) 1.616(3); C(30)–Ni(1)–
C(1) 93.8(2), C(30)–Ni(1)–N(1) 160.33(16), C(1)–Ni(1)–N(1) 89.98(19),
C(30)–Ni(1)–N(2) 89.23(19), C(1)–Ni(1)–N(2) 160.86(16), N(1)–Ni(1)–
N(2) 93.47(16), C(19)–N(1)–P(1) 118.9(4), C(19)–N(1)–Ni(1) 122.4(3),
P(1)–N(1)–Ni(1) 114.9(2), C(43)–N(2)–P(2) 116.4(3), C(43)–N(2)–
Ni(1) 123.5(3), P(2)–N(2)–Ni(1) 112.9(2), C(2)–C(1)–Ni(1) 127.0(4),
C(6)–C(1)–Ni(1) 117.1(4), C(29)–C(30)–Ni(1) 127.2(4), C(25)–C(30)–
Ni(1) 118.6(4).
1 W. Liu, J. M. Malinoski and M. Brookhart, Organometallics, 2002,
21, 2836.
2 F. A. Hicks and M. Brookhart, Organometallics, 2001, 20,
3217.
3 S. D. Ittel, L. K. Johnson and M. Brookhart, Chem. Rev., 2000, 100,
1169.
4 B. L. Small, M. Brookhart and A. M. A. Bennett, J. Am. Chem. Soc.,
1998, 120, 4049.
5 B. L. Small and M. Brookhart, J. Am. Chem. Soc., 1998, 120,
7143.
6 C. M. Killian, D. J. Tempel, L. K. Johnson and M. Brookhart,
J. Am. Chem. Soc., 1996, 118, 11664.
7 C. M. Killian, D. J. Tempel, L. K. Johnson and M. Brookhart,
J. Am. Chem. Soc., 1996, 118, 11664.
8 L. K. Johnson, C. M. Killian and M. Brookhart, J. Am. Chem. Soc.,
1995, 117, 6414.
9 L. K. Johnson, C. M. Killian and M. Brookhart, J. Am. Chem. Soc.,
1995, 117, 6414.
10 M. P. Coles, C. I. Dalby, V. C. Gibson, W. Clegg and M. R. J.
Elsegood, J. Chem. Soc., Chem. Commun., 1995, 1709.
11 G. J. P. Britovsek, V. Gibson, B. S. Kimberley, P. J. Maddox,
S. J. McTavish, G. A. Solan, A. J. P. White and D. J. Williams,
Chem. Commun., 1998, 849.
12 G. J. P. Britovsek, V. C. Gibson and D. F. Wass, Angew. Chem.,
Int. Ed., 1999, 38, 428.
13 V. C. Gibson, C. Newton, C. Redshaw, G. A. Solan, A. J. P. White
and D. J. Williams, J. Chem. Soc., Dalton Trans., 1999, 827.
14 T. R. Younkin, E. F. Connor, J. I. Henderson, S. K. Friedrich, R. H.
Grubbs and D. A. Bansleben, Science, 2000, 287, 460.
15 D. W. Stephan, F. Guerin, R. E. v. H. Spence, L. Koch, X. Gao,
S. J. Brown, J. W. Swabey, Q. Wang, W. Xu, P. Zoricak and D. G.
Harrison, Organometallics, 1999, 18, 2046.
16 D. W. Stephan, J. C. Stewart, F. Guerin, R. E. v. H. Spence, W. Xu
and D. G. Harrison, Organometallics, 1999, 18, 1116.
17 L. P. Spencer, R. Altwier, P. Wei, L. Gelmini, James Gauld and D. W.
Stephan, Organometallics, 2003, 22, ASAP.
18 S. Wingerter, H. Gornitzka, R. Bertermann, S. K. Pandey, J. Rocha
and D. Stalke, Organometallics, 2000, 19, 3890.
Fig. 7 ORTEP drawing of 14, 30% thermal ellipsoids are shown,
hydrogen atoms have been omitted for clarity. Selected bond distances
(Å) and angles (Њ): Ni(1)–C(6) 1.920(5), Ni(1)–C(6) 1.920(5), Ni(1)–
N(1) 2.020(4), Ni(1)–N(1) 2.020(4), N(1)–C(19) 1.433(6); C(6)–Ni(1)–
C(6) 94.3(4), C(6)–Ni(1)–N(1) 177.73(19), C(6)–Ni(1)–N(1) 85.4(2),
C(6)–Ni(1)–N(1) 85.4(2), C(6)–Ni(1)–N(1) 177.73(19), N(1)–Ni(1)–
N(1) 95.0(2), P(1)–N(1)–Ni(1) 108.5(2).
19 S. Wingerter, H. Gornitzka, G. Bertrand and D. Stalke, Eur. J. Inorg.
Chem., 1999, 173.
20 K. T. K. Chan, L. P. Spencer, J. D. Masuda, J. S. J. McCahill, P. Wei
and D. W. Stephan, submitted for publication.
21 C. G. Stuckwisch, J. Org. Chem., 1976, 41, 1173.
22 N. J. Curtis and R. S. Brown, J. Org. Chem., 1980, 45, 4038.
23 A. Steiner and D. Stalke, Angew. Chem., Int. Ed. Engl., 1995, 34,
1752.
that described above for 13. The geometry of 14 is two-fold
symmetry as the Ni sits on a crystallographic special position.
Approximate π-stacking of the N-bound aryl groups in 14 is
similar to that seen in 13 and results in a slightly distorted
square planar geometry about Ni. The Ni–C and Ni–N
distances in 14 of 1.920(5) Å and 2.020(4) Å respectively are
similar to those seen in 13 as is the C–Ni–N angle (85.4(2)Њ).
The fortuitous co-crystallization of the Ni() by-product
NiBr(PPh3)3, in the formation of 14, suggests that some degree
of metal reduction by the Li reagents may account for the only
moderate yields in these syntheses of transition metal species
11–14. In a related sense, Stalke and co-workers have seen evi-
dence of oxidative ligand coupling.19 In addition, in the syn-
theses described herein, it is generally observed for both the
main group and transition metal derivatives that more than
one metallated phosphinimine ligand are readily incorporated.
24 D. T. Cromer and J. B. Mann, Acta Crystallogr., Sect. A, 1968, 24,
321.
25 S. Courtenay, J. Y. Mutus, R. W. Schurko and D. W. Stephan,
Angew. Chem., Int. Ed., 2002, 41.
26 M. Moehlen, B. Neumueller and K. Dehnicke, Z. Anorg. Allg.
Chem., 1998, 624, 177.
27 K. Dehnicke and F. Weller, Coord. Chem. Rev., 1997, 158, 103.
28 K. Dehnicke and J. Straehle, Polyhedron, 1989, 8, 707–726.
29 Preliminary X-ray data for 10: a = 9.377(6) Å, b = 17.23(1) Å,
c = 18.55(1) Å, α = 85.03(1)Њ, β = 79.34(1)Њ, γ = 84.10(1)Њ.
30 A. C. Albeniz, P. Espinet, R. Manrique and A. Perez-Mateo, Angew.
Chem., Int. Ed., 2002, 41, 2363.
31 M. Retboll, A. J. Edwards, A. D. Rae, A. C. Willis, M. A. Bennett
and E. Wenger, J. Am. Chem. Soc., 2002, 124, 8348.
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32 J. Vicente, J.-A. Abad, B. Rink, F.-S. Hernandez and M. C. Ramirez
de Arellano, Organometallics, 1997, 16, 5269.
33 A. W. Kleij, R. A. Gossage, R. J. M. K. Gebbink, N. Brinkmann,
E. J. Reijerse, U. Kragl, M. Lutz, A. L. Spek and G. van Koten,
J. Am. Chem. Soc., 2000, 122, 12112.
34 J. Campora, E. Gutierrez, A. Monge, M. L. Poveda, C. Ruiz and
E. Carmona, Organometallics, 1993, 12, 4025.
35 P. E. Garrou, Chem. Rev., 1981, 81, 229.
36 C. Mealli, P. Dapporto, V. Sriyunyongwat and T. A. Albright,
Acta Crystallogr., Sect. C, 1983, 39, 995.
37 G. M. Sheldrick, SHELXTL, University of Göttingen, Germany,
1997; M. N. Burnett and C. K. Johnson, ORTEP-III: Oak Ridge
Thermal Ellipsoid Plot Program for Crystal Structure Illustrations,
Report ORNL-6895, Oak Ridge National Laboratory, Oak Ridge,
TN, USA, 1996; SAINT, XPREP, Bruker AXS Inc., Madison, WI
53711, 1198.
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