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

of ~2:1 formyl:hydride, which converted almost entirely to hydride after 1.5 hours (~1:21
formyl:hydride). All formyl was consumed after 4 hours.
Reaction of [1-Ph 1][BAr F
4] with 1 equiv [HPt][BAr F
4].
A J-Young tube was charged with 31.3 mg (0.0215 mmol) [1-Ph 1][BAr F
4], 29.2 mg (0.0215
mmol) [HPt][BAr F
4], and ~0.6 mL C 6D 5Cl. Monitoring by NMR spectroscopy revealed no
detectable reaction after 15 minutes, and only partial conversion to 2-Ph 1 after 3 hours. After 30
hours, complete conversion to the Re hydride trans-(PPh 3)Re(<strong>CO</strong>) 4H [ 1 H NMR δ -4.65 (d, J PH =
22.5 Hz); 31 P{ 1 H} NMR δ 15.7] was observed.
B. Reduction of [(Ph 2PCH 2B(C 8H 14))Re(<strong>CO</strong>) 5][OTf] ([1-M 1][OTf]).
Reaction of [1-M 1][OTf] with 1 equiv [HPt][PF 6].
A 20 mL scintillation vial was charged with 99.1 mg (0.124 mmol) [1-M 1][OTf] and 2 mL
C 6H 5Cl. With rapid stirring, 79.8 mg (0.124 mmol) [HPt][PF 6] was added in ~10 mg portions
slowly over ~5 minutes. The mixture was allowed to stir overnight, at which point it was filtered
through celite (washing with 1 mL C 6H 5Cl and 2 mL pentane), and the solvents were removed
under vacuum. The oily residue was triturated briefly with pentane and the solvents were again
removed under vacuum. The white solids were extracted with 5 mL pentane, filtered, and the
solvents removed under vacuum to give 70 mg (87%) ~95% pure 2-M 1. The side product was a
Re-CH 2-containing species (δ 5.18 d, J PH = 6.3 Hz) which had spectral characteristics ( 31 P NMR,
δ -8.9 (1P), 2.3 (1P)) similar to more completely characterized dirhenium alkyl-dioxycarbene
species 10-E 1. 1 H NMR (C 6D 6, 300 MHz): δ 1.16 (br, 2H, Ph 2PCH 2B(C 8H 14)), 1.3-1.8 (br,
Ph 2PCH 2B(C 8H 14)), 1.65 (d, J PH = 12.9 Hz, Ph 2PCH 2B(C 8H 14)), 2.02 (br, Ph 2PCH 2B(C 8H 14)), 2.30
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