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

location as [1-E 2][BF 4]. Thus we assign the product as closely related to cation 1,
[(Ph 2P(CH 2) 2B(C 8H 14)) 2Re(<strong>CO</strong>) 4][HB(C 6F 5) 4]. Heating at 50 °C for one week resulted in no
discernable reaction. Elevated temperatures (135 °C) led to decomposition of the ligands,
including the presence of cyclooctene.
NMR-scale reaction of [Na][3-E 2] with [Pt][BAr F
4] 2.
To a ~0.6 mL THF-d 8 solution of 21.0 mg (0.0199 mmol) [1-E 2][BF 4] was added 39.9 µL
(0.0399 mmol, 2 equiv) NaHBEt 3 (1.0 M in toluene) dropwise with stirring. The mixture was
filtered into a J-Young NMR tube, and NMR spectroscopy showed clean formation of [3-E 2] - .
The tube was returned to the glove box, and the contents poured onto 88.6 mg (0.0199 mmol)
[Pt][BAr F
4] 2, which was dissolved and the reaction mixture returned to the tube. NMR
spectroscopic monitoring revealed no detectable reaction of [3-E 2] - or formation of [HPt] + over
24 hours.
Reaction of [Na][3-E 2] with MeOTf.
To a 5 mL toluene suspension of 35.8 mg (0.0341 mmol) [Na][3-E 2] was added 3.9 μL (0.0341
mmol) MeOTf by syringe, with stirring. The reaction mixture was stirred 30 minutes, filtered,
washing with 0.5 mL toluene and 1 mL pentane, affording clear yellow filtrate (white solids left
on filter). The solvents were removed under vacuum, giving 27 mg (80%) yield of yellow
product. 1 H NMR (THF-d 8, 300 MHz) showed a characteristic pair of doublets at 3.97 (d, J HH =
18.8 Hz) and 4.61 (d, J HH = 18.8 Hz), along with a singlet at 3.18 (3H) for the new methyl group.
Integration of the crowded alkyl and aryl regions was not satisfactory, however. 31 P NMR (THF-
d 8, 300 MHz) showed only one product, 5.5 (d, J PP = 110.2 Hz) and 14.1 (d, J PP = 109.7 Hz).
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