Steric Effects in the Kinetics of Organometallic Reactions: A Time-Resolved Infrared Study of [(η5-C5R5)Mn(CO)2] (R = H, Me or Et) in n-heptane Solution

Fast time-resolved IR spectroscopy (microsecond timescale) is used to record the spectra and kinetics of photochemical reactions of [(η⁵-C₅R₅)Mn(CO)₃] (R = H, Me or Et) in n-heptane solution; second-order rate constants for reaction with H₂, N₂ and CO are ca. six times faster for [(C₅Et₅)Mn(CO)₂(n-hept)] than for [(C₅H₅)Mn(CO)₂(n-hept)] while the rate constants for the reaction of all three [(C₅R₅)Mn(CO)₂(n-hept)] intermediates with PPh₃ are almost identical.