Heterolytic activation of hydrogen as a trigger for iridium complex promoted activation of carbon-fluorine bonds

The cationic iridium(III) complex IrCF(3)(CO)(dppe)(DIB)]BARF](2) where DIB = o-diiodobenzene, dppe = 1,2-bis(diphenylphosphino)ethane, and BARF = B(3,5-(CF(3))(2)C(6)H(3))(4)(-) undergoes reaction in the presence of dihydrogen to form IrH(2)(CO)(2)(dppe)](+) as the major product. Through labeling studies and (1)H and (31)P(1)H] NMR spectroscopies including parahydrogen measurements, it is shown that the reaction involves conversion of the coordinated CF(3) ligand into carbonyl. In this reaction sequence, the initial step is the heterolytic activation of dihydrogen, leading to proton generation which promotes alpha-C-F bond cleavage. Polarization occurs in the final IrH(2)(CO)(2)(dppe)](+) product by the reaction of H(2) with the Ir(I) species Ir(CO)(2)(dppe)](+) that is generated in the course of the CF(3) --> CO conversion.