Photochemical reaction of dinuclear manganese carbonyl compounds with tributyltin hydride and with silanes

Article abstract of DOI:10.1021/ja00024a021

The photochemical reactions of Mn₂(CO)₈L₂ (L = CO, PMe₃, P(n-Bu)_3, P(i-Pr)₃) with HSnBu₃ or HSiEt₃ in hexane solutions have been studied, using 366- or 313-nm irradiation, and under CO or Ar atmospheres. Under CO, 1.1-3.7 atm, the products of the reaction of Mn₂(CO)₁₀ with HSnBu₃ are HMn(CO)₅ and Bu₃SnMn(CO)₅. Under Ar or low CO pressures, a third product, assigned as HMn(CO)₄(SnBu₃)₂, is formed at the expense of Bu₃SnMn(CO)₅. For a given photon flux, the reaction rate is inversely related to [CO]. The behavior of the system is consistent with a reaction pathway that involves oxidative addition of the hydride to the coordinatively unsaturated metal center formed upon CO loss. Analogous results are observed for the phosphine-substituted manganese carbonyl dinners. Reaction with HSiEt₃ proceeds much more slowly under equivalent conditions of irradiation. In the reaction with Mn₂(CO)₅, only HMn(CO)₅ is seen as a significant product, with trace amounts of Et₃SiMn(CO)₅ also observed. These results are also consistent with oxidative addition to the Co-loss product as the only pathway for the photochemical reaction. None of the manganese dimers undergo photochemical reaction with either fluorene or triphenylmethane, in spite of the comparatively low C-H bond energy in each case.