1664 Organometallics, Vol. 28, No. 6, 2009
Fang et al.
CH2 (Ha4)), 4.72 (m (7 peaks), 1H, allyl CH (Ha5)), 6.8-7.4 (m,
16H, Ph H), 7.51 (ddd, 2H, Ph H), 7.85 (ddd, 2H, Ph H). 1H NMR
(THF-d8) (12May05): δ -0.113 (s, 9H, Si(CH3)3) and -0.174 (s,
(w), 1640 (br, m), 1832 (br, w), 1971 (vs, ν(CO)), 2029 (vs, ν(CO)),
2047 (vs, ν(CO)), 2895 (w), 2952 (m), 3057 (w), 3410 (br, m).
Synthesis of 6. A yellow THF solution (7 mL) of compound 1
(0.224 g, 0.264 mmol) was heated for 16 h at 60 °C, resulting in
formation of 6 (100% yield by in situ 31P). The THF was removed
under dynamic vacuum, and the solid was dissolved in ether (5
mL). The solution was reduced in volume to approximately 1 mL
by vacuum and was kept at -20 °C overnight in the drybox to
produce 0.131 g of an orange, crystalline solid (6). The supernatant
liquid was decanted, further reduced in volume, and cooled again
to obtain a second crop (0.030 g) of 6. The overall yield of 6 was
0.161 g (71.8%). At room temperature, 30% of 1 (16 mg in 0.5
mL dry C6D6, 31P) was converted to 6 over 12 days. The conversion
of 1 (25 mg in 0.5 mL dry C6D6) to 6 was completed (100% yield
by 31P) after 36 h heating at 54 °C. Complex 6 is very soluble in
benzene (>176 mg/ml) and ether (>300 mg/ml). It is sensitive to
moisture; however it remains stable in dry benzene at 60 °C for 5
days. Anal. Calcd for C43H60LiN2OP2RhSi2: C, 60.8; H, 7.1; N,
3.3. Found: C, 60.7; H, 7.1; N, 3.3. A quantity of 6 (0.088 g) was
dissolved in 0.5 mL of C6H6 under argon in a 5 mm NMR tube
equipped with a Teflon cap. Red crystals of 6 · 1.5C6H6 were formed
after the sample was kept at room temperature for about 1 week,
and its crystal structure was determined. 1H NMR (C6D6): δ -0.245
(s, 9H, Si(CH3)3), -0.098 (s, 9H, Si(CH3)3), 1.08 (t, 6H,
3
9H, Si(CH3)3), 2.79 (d, 1H, JHH ) 13, allyl CH2 (Ha1)), 2.84 (d,
1H, 3JHH ) 6.4, allyl CH2 (Ha2)), 3.25 (d, 1H, 3JHH ) 12, allyl CH2
(Ha3)), 3.95 (dd, 1H, JHH ) 6.8, 2.4, allyl CH2 (Ha4)), 4.91 (m (7
peaks), 1H, allyl CH (Ha5)), 6.9-7.5 (m, 18H, Ph H), 7.57 (ddd,
2
2H, Ph H). 31P{1H} NMR (C6D6): δ 49.3 (dd, PNRh, JPP ) 57,
2
2
2JPRh ) 18), 39.5 (d, JPP ) 57, JPRh ) 0). 31P{1H} NMR (THF-
d8) (12May05): δ 54.6 (dd, PNRh, 2JPP ) 57, 2JPRh ) 18), 45.9 (d,
2JPP ) 57, JPRh ) 0). 13C{1H} NMR (C6D6): δ 0.9 (d in 13C{1H,
2
13P}, PdCRh, JCRh ) 14.0), 3.87 (d, Si(CH3)3, JCP ) 3.1), 4.1
1
3
3
3
(dd, Si(CH3)3, JCRh ) 0.57, JCP with P at 49.3 ppm ) 3.0), 49.7
(s, allyl CH2), 61.1 (s, allyl CH2), 105.4 (s, allyl CH), 127.2-133.1
1
1
(Ph CH), 137.5 (d, Ph C, JCP ) 79), 138.6 (dd, Ph C, JCP ) 77,
3JCPh ) 1.4), 138.7 (dd, Ph C, JCP ) 82, JCPh ) 1.3), 139.2 (dd,
1
3
Ph C, 1JCP ) 79, 3JCPh ) 0.9), 188.4 (d, CO, 1JCRh ) 64), 189.9 (d,
1
CO, JCRh ) 70).
1
For the minor diasteromers: H NMR (C6D6): δ 0.07 (s, 9H,
Si(CH3)3) and 0.17 (s, 9H, Si(CH3)3), 1.34 (d, 1H, 3JHH ) 12, allyl
CH2 (Hb )), 2.59 (d, 1H, 3JHH ) 13, allyl CH2 (Hb )), 3.98 (dd, 1H,
1
2
3
JHH ) 7.1, 2.3, allyl CH2 (Hb )), 4.03 (dd, 1H, JHH ) 6.4, 1.9, allyl
4
5
CH2 (Hb )), 4.89 (m (7 peaks (Hb )), 1H, allyl CH), 6.8-7.4 (m,
16H, Ph H), 7.66 (ddd, 2H, Ph H), 8.25 (ddd, 2H, Ph H). 1H NMR
(THF-d8): δ -0.107 (s, 9H, Si(CH3)3) and -0.221 (s, 9H, Si(CH3)3),
3
(CH3CH2)2O, JHH ) 7.1), 1.15 (m, 1H, cod CH2), 1.47 (m, 1H,
3
1
3
cod CH2), 1.57 (m, 2H, cod CH2), 1.80 (m, 1H, cod CH2), 1.94
(m, 2H, cod CH2), 2.41 (m, 1H, cod CH2), 2.90 (ddd, PC(H)P,
1.19 (d, 1H, JHH ) 12, allyl CH2 (Hb )), 2.68 (d, 1H, JHH ) 13,
2
4
allyl CH2 (Hb )), 3.81 (d, 1H, JHH ) 6.4, 1.8, allyl CH2 (Hb )),
2
2JHP ) 8.0 with 31P peak at 29 ppm, JHP ) 13.0 with 31P peak at
3
3.97 (dd, 1H, JHH ) 7.2, 2.4, allyl CH2 (Hb )), 5.05 (m (7 peaks
19 ppm, 2JHRh ) 2.8), 3.31 (q, 4H, (CH3CH2)2O, 3JHH ) 7.1), 3.75
(m, 2H, cod CH), 3.93 (m, 1H, cod CH), 4.35 (m, 1H, cod CH),
7.03 (m, 3H, Ph H), 7.08 (m, 3H, Ph H), 7.21 (m, 5H, Ph H), 7.57
(m, 3H, Ph H), 7.68 (t, 1H, Ph H, 3JHP ) 7.3 Hz with P at 18 ppm,
3JHH ) 7.3), 7.87 (dd, 2H, Ph H, 3JHP ) 12.8 Hz coupled with P at
5
(Hb )), 1H, allyl CH), 6.9-7.5 (m, 18H, Ph 8.02 (ddd, 2H, Ph H).
31P{1H} NMR (C6D6): δ 56.5 (dd, PNRh, JPP ) 57, JPRh ) 18),
2
2
36.5 (d, JPP ) 58, JPRh ) 0). 31P{1H} NMR (THF-d8): δ 61.8
2
2
2
2
2
2
(dd, PNRh, JPP ) 57, JPRh ) 18), 42.5 (d, JPP ) 57, JPRh ) 0).
13C{1H} NMR (C6D6): δ 0.2 (d in 13C{1H, 13P}, PdCRh, JCRh
)
1
14.2), 3.89 (d, Si(CH3)3, 3JCP obsured), 4.0 (dd, 3JCRh ) 0.57, 3JCP
with P at 56.5 ppm ) 2.8), 48.0 (s, allyl CH2), 67.8 (s, allyl CH2),
28 ppm), 8.35 (m, 2H, Ph H, JHP ) 10.7 Hz with P at 28 ppm,
3
3JHH ) 7.8). 31P{1H} NMR (C6D6): δ 28.9 (dd, JPP ) 14.8, JPRh
) 4.0, PPh2), 18.5 (d, 2JPP ) 14.8, 2JPRh ) 0, PPh). 13C{1H} NMR
2
2
109.7 (s, allyl CH), 127.2-133.1 (Ph CH), 138.0 (d, Ph C, 1JCP
)
74), 138.1 (dd, Ph C, 1JCP ) 73, 3JCPh ) 1.2), 138.9 (dd, Ph C, 1JCP
3
3
(C6D6): δ 3.64 (d, Si(CH3)3), JCP ) 4.1), 4.14 (d, Si(CH3)3), JCP
) 3.6), 14.6 (s, Et2O), 30.1, 30.2, 30.7, 31.8 (s, cod CH2), 37.9 (m,
) 77, 3JCPh ) 1.4), 139.7 (dd, Ph C, 1JCP ) 76, 3JCPh ) 0.7), 189.0
1
1
1
1
PC(H)P, JCRh ) 25.8 (obtained in 13C{1H, 31P}), JCP obscured),
(d, CO, JCRh ) 64), 189.5 (d, CO, JCRh ) 70).
1
65.5 (s, Et2O CH2), 76.5 (d, cod CH, JCRh ) 11.9), 77.1 (d, cod
The compound is unchanged after 1-day exposure to air
(Microscope IR). Microscope IR: 664 (m), 695 (s), 717 (s), 740
(s), 770(s), 834 (br s), 922 (m), 999 (w), 1012 (w), 1028 (w), 1095
(br s), 1138 (s), 1161 (s), 1250 (s), 1311 (w), 1399 (w), 1436 (s),
1482 (m), 1572 (w), 1777 (w), 1823 (w), 1925 (m, sh), 1954 (vs,
br, υ(CO)), 2009 (m, sh, υ(CO)), 2027 (vs, br, υ(CO)), 2894 (m),
2964 (m), 3055 (m).
CH, 1JCRh ) 10.9), 82.3 (d, cod CH, 1JCRh ) 6.7), 82.3 (d, cod CH,
1
1JCRh ) 7.8), 122.5-135.1 (m, Ph CH), 137.1 (d, 2 Ph C, JCP
)
96.8, 3JCP ) 5.6), 140.4 (d, Ph C, 1JCP ) 89.6, 3JCP ) 3), 142.5 (d,
Ph C, 1JCP ) 92.5, 3JCP ) 10.0), 145.4 (d, Ph C, 1JCP ) 134.7, 3JCP
1
2
7
not observed), 177.8 (t, CRh, JCRh ) 36.0, JCP ) 35.8). Li{1H}
NMR (C6D6): δ 0.99 (s).
Syntheses of 7. (a) Directly from LiC(H)(Ph2PdNSiMe3)2
and [RhCl(cod)]2. To a benzene solution (10 mL) of [RhCl(cod)]2
(0.132 g, 0.268 mmol) was added 4.7 mL of a benzene/pentane
solution of LiC(H)(Ph2PdNSiMe3)2 (0.1137 M, total moles: 0.534
mmol) dropwise. The resultant yellow solution was stirred for 3
days at room temperature. The solvent was removed under vacuum,
and the yellow solids obtained were extracted with 20 mL of
pentane followed by 10 mL of hexane. The insoluble solid (LiCl)
was removed by centrifugation. The orange solution thus obtained
was reduced in vacuo to approximately 2 mL and kept at -15 °C
overnight. Orange crystals of 7 (0.160 g) were formed, from which
crystals suitable for X-ray diffraction were obtained. The supernatant
liquid was decanted, further reduced in volume, and cooled again
to obtain a second crop (0.208 g) of 7. The overall yield of 7 was
0.368 g (0.479 mmol, 89.6%). Anal. Calcd for C39H51N2P2RhSi2:
Synthesis of 5. A degassed orange THF/ether (1:1 ratio) solution
(6 mL) of compound 3 (0.058 g, 0.059 mmol) was reacted with
CO at 1 atm pressure in a 50 mL bulb tube with valve at room
temperature. The mixture was stirred for 24 h. No obvious color
change was observed. In situ 31P NMR showed 3 was converted to
5 quantitatively. The solvent was removed by dynamic vacuum
for 1 h, leaving an oily product. The product was then extracted
with ether (3 mL) and filtered, and then solvent was removed in
dynamic vacuum for 12 h to yield 37 mg (0.042 mmol) of 5 (yield:
71%) as a yellow powder. Anal. Calcd for C35H38N2O4P2Rh2Si2:
1
C, 48.1; H, 4.4; N, 3.2. Found: C, 47.6; H, 4.3; N, 2.8. H NMR
(C6D6): δ 0.10 (s, 18H, Si(CH3)3), 6.83 (m, 4H, Ph H), 6.97 (m,
6H, Ph H), 7.05 (m, 2H, Ph H), 7.47 (m, 4H, Ph H), 7.62 (m, 4H,
Ph H). 31P{1H} NMR (C6D6): δ 52.1 (close to dd, J ) 7.2, 9.4).
31P{1H} NMR (THF-d8): δ 52.9 (close to dd, JPRh ) 6.9 and 9.2).
13C{1H} NMR (C6D6): δ 3.7 (s, Si(CH3)3)), 127.7-133.4 (Ph CH),
1
C, 60.9; H, 6.7; N, 3.6. Found: C, 61.3; H, 6.5; N, 3.5. H NMR
1
1
(C6D6): δ 0.198 (s, 18H, Si(CH3)3), 1.47 (m, 4H, cod CH2), 1.86
(t, 1H, PC(H)P, 2JHP ) 10.6), 2.17 (br s, 4H, cod CH2), 4.22 (br s,
4H, cod CH), 6.88 (m, 6H, Ph H), 7.15 (m, 2H, Ph H), 7.22 (m,
135.4 (d, JCP ) 83, Ph C), 136.2 (d, JCP ) 78, Ph C), 187.4 (d,
1
1
3
CO, JCRh ) 67), 188.4 (dt, CO, JCRh ) 68, JCP ) 2.0), RhCRh
not observed. Microscope IR: 667 (m), 692 (s), 722 (m), 740 (m),
773 (s), 834 (vs), 998 (w), 1028 (w), 1067 (s), 1091 (s), 1106 (s),
1122 (m), 1184 (w), 1248 (s), 1312 (w), 1435 (s), 1481 (w), 1589
1
4H, Ph H), 7.51 (m, 4H, Ph H), 8.28 (m, 4H, Ph H). H NMR
(THF-d8): δ -0.09 (s, 18H, Si(CH3)3), 1.54 (m, 4H, cod CH2), 1.72