Photochemistry of Gas-Phase Mn₂(CO)₁₀ and Re₂(CO)₁₀: Mass Spectrometric Evidence for a Dinuclear Primary Photoproduct

The photochemistries of Mn₂(CO)₁₀ and Re₂(CO)₁₀ following excitation at 337 nm in the region of their σ^⋆ ← σ bands are investigated under collision-free conditions. Results suggest that in addition to the M(CO)₅ photofragments previously reported in the molecular beam study of Freedman and Bersohn, partially decarbonylated dimetal photofragments are also produced. Thus, in the gas phase, as in solution, both dissociative CO loss and M-M bond scission appear to be primary photochemical processes in the dimetal decacarbonyl systems.