Identification of Photogenerated Intermediates by Electrospray Ionization Mass Spectrometry

Solutions of [CpFebz]PF6 (Cp = η5-cyclopentadienyl, bz = η6-benzene) were photolyzed in the tip of an electrospray ionization source and the photoproducts analyzed by mass spectrometry. Two main series of products were found in acetonitrile (AN): [CpFe(AN)1-3]+ and [Fe(AN)3-6]2+. In 1,2-dichloroethane solutions containing cyclohexene oxide (CHO), three main product series were detected: [(H2O)Fe(CHO)4-12]2+, [(H2O)CpFe(CHO)1-3]+, and [X(CHO)0-5]+, where X+ (m/z = 140) is a non-iron species. Involvement of these CHO-containing products in initiating epoxide polymerization is discussed.