An ultrafast time-resolved UV/visible absorption study of the UV photochemistry of [(η5-C5H5)Fe(CO)2]2

An ultrafast time-resolved UV/visible absorption study of the UV photochemistry of [CpFe(CO)2]2 (Cp = η5-C5H5) in cyclohexane solution has shown that the long-lived CO-loss product, Cp2Fe2(μ-CO)3, is produced within 40 ps. The immediate precursor has a lifetime of 15 ps and may be assigned preliminarily to the coordinatively unsaturated CO-loss product, (Cp)(CO)Fe(μ-CO)2Fe(Cp). The initial transient absorption decays with a lifetime of 1.6 ps, which defines the upper limit for the timescale of CO loss.