Electron spin resonance investigations of the photo-oxidation of decacarbonyldimanganese and related complexes

Abstract

An e.s.r. study has been made of the photolytic reactions of decacarbonyldimanganese derivatives in the presence of air or dioxygen in solution at low temperatures. E.s.r. parameters for the species [Mn(CO)₄L(O₂)][L = CO, PPh₃ PBuⁿ₃, or P(OEt)₃] are presented and oxygen-17 labelling of the species where L = CO has given isotropic coupling constants for the two atoms of the dioxygen moiety of 2.2 ± 0.1 and 2.05 ± 0.1 mT. Frozen-solution spectra of [Mn(CO)₅(O₂)] have been analysed and the results are discussed in terms of the bonding in the complex. Related photo-oxidation studies of other binuclear carbonyl complexes are reported and a species which is probably [Fe(η-C₅H₅)(CO)₂(O₂)] has been identified by e.s.r. spectroscopy.