Homogeneous CO Hydrogenation: Ligand Effects on the Lewis Acid ...

Synthesis of mer,trans-(Ph 2PCHCH 2) 2Mn(<strong>CO</strong>) 3Br.
A 100 mL Teflon-stoppered pressure vessel was charged with 1.612 g (5.86 mmol) Mn(<strong>CO</strong>) 5Br,
2.49 g (11.7 mmol) diphenylvinylphosphine, 25 mL toluene, and a magnetic stirbar. The orange
solution with some undissolved solids was sealed and heated to 120 °C, and the mixture
darkened, with almost all of the solids dissolved. After 24 hours, the reaction mixture was
allowed to cool to room temperature, during which time yellow powder precipitated and brown
crystals grew, leaving an orange solution. The solids were collected on a frit, and washed with 10
mL toluene and 10 mL pentane, and then dried under vacuum. When the brown crystals were
pulverized, they yielded yellow powder. Drying the powder afforded 2.48 g (66%) mer,trans-
(Ph 2PCHCH 2) 2Mn(<strong>CO</strong>) 3Br. 1 H NMR (CD 2Cl 2, 500 MHz): δ 5.18 (t, J = 17.6 Hz, 2H,
Ph 2PCHCH 2), 6.01 (dd, J = 12.0, 35.2, 2H, Ph 2PCHCH 2), 7.24 (m, 2H, Ph 2PCHCH 2), 7.47 (br,
12H, 2H, Ph 2PCHCH 2), 7.68 (br, 8H, Ph 2PCHCH 2). 31 P{ 1 H} NMR (THF-d 8, 121 MHz): δ 49.0.
13 C{ 1 H} NMR (CD2Cl 2, 126 MHz): δ 128.77 (t, J PC = 4.7 Hz), 130.03, 130.72, 133.87 (t, J PC =
4.8 Hz), 134.01 (m), 135.23 (m), 217.21 (br m, trans-<strong>CO</strong>), 223.39 (<strong>CO</strong>). IR (CH 2Cl 2): ν <strong>CO</strong> 2039
(w), 1954 (s), 1912 (m) cm -1 . HRMS (FAB + ): m/z calcd for C 31H 26BrMnO 3P 2: 641.9921. Found:
641.9866.
S25