Rhodium Phosphinite Pincer Complex
Organometallics, Vol. 25, No. 9, 2006 2299
temperature factors and on ring planarity, final R1 ) 0.0792 (based
on F2) for data with I > 2σ(I) and, R1 ) 0.0969 on 12 734
reflections, goodness-of-fit on F2 ) 1.044, largest electron density
peak ) 3.265 e Å-3. Some disorder was seen on one-half of the
second dimer, and some atoms have been modeled in two alternate
positions.
(C6D6): 172.20 (d, 1JRh,P ) 133.9 Hz). 1H NMR (C6D6): 7.35 (d,
2JH,H ) 7.0 Hz, 2H, Ar), 6.95 (m, 2H, Ar), 6.85 (t, 3JH,H ) 8.4 Hz,
2H, Ar), 6.81 (d, 3JH,H ) 8.4 Hz, 2H, Ar), 3.90 (dd, 3JP,H) 4.2 Hz,
2
3JH,Rh ) 7.0 Hz, CH2-Ar) 2.33 (m, JP,H ) 7.0 Hz, 4H,
3
3
P-CH(CH3)2), 1.32 (dd, JH,H ) 8.4 Hz, JP,H ) 16.7 Hz, 6H,
3
3
P-CH(CH3)2), 1.18 (dd, JH,H ) 8.4 Hz, JP,H ) 16.6 Hz, 6H,
3
3
P-CH(CH3)2), 1.14 (dd, JH,H ) 7.0 Hz, JP,H ) 12.5 Hz, 6H,
Reaction of 4a,b with CO. Formation of (POCOP)Rh(CO)
(5). To a C6D6 solution (0.5 mL) of 4a,b (10 mg, 0.021 mmol) in
a septum-capped NMR tube was added 1 equiv of CO (0.021 mmol,
0.47 mL), leading to a color change to yellow and the immediate
formation of 6. The solvent was removed under vacuum, resulting
in a yellow solid in 96% (9.6 mg) yield. 31P{1H} NMR (C6D6):
204.9 (d, 1JRh,P ) 155.6 Hz).1H NMR (C6D6): 6.95 (t, 3JH,H ) 7.4
Hz, 1H, Ar), 6.82 (d, 3JH,H ) 7.9 Hz, 2H, Ar), 2.05 (m, 3JH,H ) 7.0
Hz, 4H, P-CH(CH3)2), 1.13 (m, 24H, P-CH(CH3)2 ). 13C{1H}
3
3
P-CH(CH3)2), 0.94 (dd, JH,H ) 7.0 Hz, JP,H ) 13.9 Hz, 6H,
P-CH(CH3)2). 13C{1H} NMR (C6D6): 166.73 (t, JC,P ) 6.7 Hz,
2
C
ipso, Rh-Ar), 148.60 (td, 2JRh,C ) 2.5 Hz,3JP,C ) 5.2 Hz, quaternary
C, benzyl ring), 137.62 (dt, 3JRh,C ) 32.6 Hz, 3JP,C ) 6.0 Hz, Ar of
benzyl ring), 131.41 (s, Ar of benzyl ring), 129.24 (s, Ar of benzyl
ring), 126.92 (s, Ar), 126.53 (s, Ar), 106.63 (t, 2JP,C ) 5.9 Hz, Ar),
2
2
29.25 (t, JP,C) 8.4 Hz, P-CH(CH3)2), 27.85 (td, JRh,C ) 0.96
Hz, JP,C ) 12.1 Hz, P-CH(CH3)2), 23.81 (dt,2JRh,C ) 25.9 Hz,
1
2JP,C ) 3.8 Hz, CH2-Ar, the assignment of this carbon was
determined by 13C DEPT NMR), 19.54 (t,2JP,C ) 5.0 Hz, P-CH-
(CH3)2), 19.38 (s, P-CH(CH3)2), 16.87 (t, 2JP,C ) 4.4 Hz, P-CH-
(CH3)2), 15.52 (s, P-CH(CH3)2). Anal. Calcd for C25H38BrO2P2-
Rh: C, 52.59; H, 6.71. Found: C, 52.33; H, 6.65.
1
2
NMR (C6D6): 200.75 (dt, JRh,C ) 58.5 Hz, JP,C ) 9.9 Hz, Rh-
CO), 169.83 (t, 2JP,C ) 8.9 Hz, Cipso, Rh-Ar), 146.42 (dt, 1JRh,C
)
2
25.2 Hz, JP,C ) 9.9 Hz, Ar), 130.52 (s, Ar), 105.93 (t, JP,C ) 7.0
Hz, Ar), 31.84 (td, 2JRh,C ) 2.2 Hz, 1JP,C ) 12.2 Hz, P-CH(CH3)2),
19.69 (t,2JP,C ) 4.6 Hz, P-CH(CH3)2), 18.83 (s, P-CH(CH3)2).
IR: 1962 cm-1, νCO. Anal. Calcd for C19H31O3P2Rh: C, 48.32; H,
6.62. Found: C, 48.45; H, 6.56.
Reaction of 4a,b with Benzyl Bromide. Formation of
(POCOP)Rh(CH2Ph)(Br) (9). To a benzene solution (1 mL) of
complexes 4a,b (20 mg, 0.042 mmol) was added 1 equiv of benzyl
bromide (7.2 mg, 0.042 mmol), leading to an immediate color
change to deep red. The solvent was removed under vacuum,
resulting in a deep red solid in 98% (25.5 mg) yield. 31P{1H} NMR
Reaction of 4a,b with Ethylene. Formation of (POCOP)Rh-
(C2H4) (6). To a C6D6 solution (0.5 mL) of 4a,b (10 mg, 0.021
mmol) in a septum-capped NMR tube was added 1 equiv (0.021
mmol, 0.47 mL) of ethylene, resulting in a slight change of color
from dark yellow to brownish-yellow. The solvent was removed
under vacuum, resulting in a brownish-yellow oil in 98% (9.8 mg)
1
1
(C6D6): 173.6 (d, JRh,P ) 132.5 Hz). H NMR (C6D6): 7.35 (d,
2JH,H ) 7.5 Hz, 2H, Ar), 6.97 (m, 2H, Ar), 6.84 (t, 3JH,H ) 7.5 Hz,
3
3
1
1
yield. 31P{1H} NMR (C6D6): 206.78 (d, JRh,P ) 155.9 Hz). H
2H, Ar), 6.82 (d, JH,H ) 8.5 Hz, 2H, Ar), 3.95 (dd, JP,H ) 3.1
3
2
NMR (C6D6, 60 °C): 6.96 (t, 3JH,H ) 7.1 Hz, 1H, Ar), 6.9 (d, 3JH,H
Hz, JRh,H ) 6.1 Hz, CH2-Ar) 2.36 (m, JP,H ) 7.0 Hz, 4H,
3
3
2
3
P-CH(CH3)2), 1.38 (dd, JH,H ) 8.5 Hz, JP,H ) 16.7 Hz, 6H,
) 7.8 Hz, 2H, Ar), 2.78 (td, JRh,H ) 1.4 Hz, JP,H ) 2.6 Hz, 4H,
3
3
3
P-CH(CH3)2), 1.19 (dd, JH,H ) 8.5 Hz, JP,H ) 17.4 Hz, 6H,
bound C2H4), 2.20 (m, JH,H ) 7.1 Hz, 4H, P-CH(CH3)2), 1.13
3
3
3
3
P-CH(CH3)2), 1.06 (dd, JH,H ) 6.5 Hz, JP,H ) 13.0 Hz, 6H,
(dd, JH,H ) 6.8 Hz, JP,H ) 13.5 Hz, 12H, P-CH(CH3)2), 1.03
3
3
3
3
(dd, JH,H ) 7.8 Hz, JP,H ) 16.2 Hz, 12H, P-CH(CH3)2). 13C-
P-CH(CH3)2), 0.93 (dd, JH,H ) 6.8 Hz, JP,H ) 14.0 Hz, 6H,
2
2
{1H} NMR (C6D6): 167.73 (t, JP,C ) 10.2 Hz, Cipso, Rh-Ar),
P-CH(CH3)2). 13C{1H} NMR (C6D6): 166.50 (t, JP,C ) 6.6 Hz,
2
3
145.58 (d, Ar), 126.50 (s, Ar), 105.65 (t, 2JP,C ) 7.4 Hz, Ar), 47.33
Cipso, Rh-Ar), 148.52 (td, JRh,C ) 2.4 Hz, JP,C ) 5.4 Hz,
1
1
3
(br d, JRh,C ) 5.6 Hz, bound C2H4), 31.99 (t, JP,C ) 11.9 Hz,
quaternary carbon of benzyl ring), 139.14 (dt, JRh,C ) 33.4 Hz,
2
P-CH(CH3)2), 19.64 (t, JP,C ) 3.1 Hz, P-CH(CH3)2), 18.65 (s,
3JP,C ) 5.4 Hz, Ar of benzyl ring), 131.50 (s, Ar of benzyl ring),
P-CH(CH3)2). Anal. Calcd for C20H35O2P2Rh: C, 50.86; H, 7.47.
129.30 (s, Ar of benzyl ring), 127.01 (s, Ar), 126.51 (s, Ar), 106.70
2
2
Found: C, 51.06; H, 7.41.
(t, JP,C ) 6.2 Hz, Ar), 29.61 (t, JP,C ) 8.6 Hz P-CH(CH3)2),
28.30 (td, 2JRh,C ) 0.96 Hz, 1JP,C ) 12.4 Hz, P-CH(CH3)2), 23.93
Reaction of 4a,b with MeI. Formation of (POCOP)Rh(Me)-
(I) (7). To a benzene solution (1 mL) of complexes 4a,b (20 mg,
0.042 mmol) was added 1 equiv of MeI (6 mg, 0.042 mmol),
resulting in an immediate color change to deep red. The solvent
was removed under vacuum, resulting in a red solid in 70% (14
(dt,2JRh,C ) 25.4 Hz, JP,C ) 3.8 Hz, CH2-Ar, the assignment of
2
this carbon was determined by 13C DEPT NMR), 19.70 (t,2JP,C
)
)
2
4.8 Hz, P-CH(CH3)2), 19.30 (s, P-CH(CH3)2), 17.53 (t, JP,C
4.2 Hz, P-CH(CH3)2), 15.70 (s, P-CH(CH3)2). Anal. Calcd for
1
mg) yield. 31P{1H} NMR (C6D6): 178.41 (d, JRh,P ) 122.6 Hz).
C25H38BrO2P2Rh: C, 48.80; H, 6.22. Found: C, 48.89; H, 6.29.
3
3
1H NMR (C6D6): 6.93 (t, JH,H ) 7.9 Hz, 1H, Ar), 6.77 (d, JH,H
Reaction of 9 with AgBF4. Formation of [(POCOP)Rh-
(CH2Ph)][BF4] (10). To a benzene solution (1 mL) of complex 9
(25.5 mg, 0.041 mmol) was added 1 equiv of AgBF4 (8.2 mg, 0.041
mmol) in THF (2 mL), resulting in formation of a white-gray
precipitate of AgBr and a color change to red. The precipitate was
removed by filtration through a Celite pad, and the solvent was
removed from the filtrate under vacuum, resulting in a red solid in
98% (25 mg) yield. 31P{1H} NMR (C6D6): 173.4 (d, 1JRh,P ) 138.3
2
) 7.9 Hz, 2H, Ar), 2.50 (m, JP,H ) 7.0 Hz, 2H, P-CH(CH3)2),
2.37 (m, 2H, P-CH(CH3)2), 1.59 (td, 3JP,H ) 5.5 Hz, 2JRh,H ) 2.6
3
3
Hz, 3H, Rh-CH3), 1.36 (dd, JH,H ) 7.8 Hz, JP,H) 16.4 Hz, 6H,
3
3
P-CH(CH3)2), 1.27 (dd, JH,H ) 7.2 Hz, JP,H ) 14.5 Hz, 6H,
3
3
P-CH(CH3)2), 1.18 (dd, JH,H ) 7.6 Hz, JP,H ) 16.7 Hz, 6H,
3
3
P-CH(CH3)2), 0.95 (dd, JH,H ) 7.0 Hz, JP,H ) 14.1 Hz, 6H,
P-CH(CH3)2). 13C{1H} NMR (C6D6): 165.99 (t, JP,C ) 6.7 Hz,
2
2
1
2
C
ipso, Rh-Ar), 128.29 (s, Ar), 126.86 (s, Ar), 106.68 (t, JP,C
)
Hz). H NMR (C6D6): 7.25 (d, JH,H ) 7.7 Hz, 2H, Ar), 7.05 (m,
2
2H, Ar), 6.90 (t, 3JH,H ) 7.7 Hz, 2H, Ar), 6.70 (d, 3JH,H ) 8.1 Hz,
6.1 Hz, Ar), 30.91 (t, JP,C ) 10.8 Hz, P-CH(CH3)2), 28.37 (td,
2JRh,C ) 2.1 Hz, 1JP,C ) 11.9 Hz, P-CH(CH3)2), 18.33 (dt,2JP,C
2.6 Hz, 2JRh,C ) 29.3 Hz, P-CH(CH3)2), 17.75 (s, P-CH(CH3)2),
3
3
)
2H, Ar), 4.0 (dd, JP,H) 2.9 Hz, JRh,H ) 5.9 Hz, CH2-Ar) 2.50
2
(m, JP,H ) 7.0 Hz, 4H, P-CH(CH3)2), 1.22 (m, 12H, 2 ×
1
2
3
3
16.76 (s, P-CH(CH3)2), 1.78 (dt, JRh,C ) 26.8 Hz, JP,C ) 5.7
Hz, Rh-CH3). Anal. Calcd for C19H34IO2P2Rh: C, 38.93; H, 5.85.
Found: C, 39.12; H, 5.93.
P-CH(CH3)2), 1.06 (dd, JH,H ) 7.0 Hz, JP,H ) 13.5 Hz, 6H,
3
3
P-CH(CH3)2), 0.96 (dd, JH,H ) 7.0 Hz, JP,H ) 13.5 Hz, 6H,
P-CH(CH3)2). 13C{1H} NMR (C6D6): 167.20 (t, JP,C ) 6.2 Hz,
2
2
3
Cipso, Rh-Ar), 147.50 (td, JRh,C ) 2.5 Hz, JP,C ) 5.3 Hz,
quaternary of carbon of benzyl ring), 134.03 (s, Ar), 132.12 (s,
Ar), 129.70 (s, Ar of benzyl ring), 128.92 (s, Ar of benzyl ring),
Reaction of 4a,b with Benzyl Chloride. Formation of
(POCOP)Rh(CH2Ph)(Cl) (8). To a benzene solution (1 mL) of
complexes 4a,b (20 mg, 0.042 mmol) was added 1 equiv of benzyl
chloride (5.4 mg, 0.042 mmol), leading to an immediate color
change to deep red. The solvent was removed under vacuum,
resulting in a deep red solid in 98% (23.7 mg) yield. 31P{1H} NMR
2
2
127.50 (s, Ar), 107.30 (t, JP,C ) 5.8 Hz, Ar), 30.2 (t, JP,C ) 8.7
1
Hz P-CH(CH3)2), 27.2 (t, JP,C ) 13.1 Hz, P-CH(CH3)2), 26.32
(dt,2JRh,C ) 27.6 Hz, JP,C ) 3.2 Hz, CH2-Ar, the assignment of
2