Low temperature photochemistry of . Stabilization of an intermediate photoproduct in a decomposition reaction

Article abstract of DOI:10.1016/0022-328X(88)80078-0

The complex (I), a photoproduct from , is itself photolabile.The UV, IR, resonance Raman spectra of I are described and used for the interpretation of its photochemical behaviour.Irradiation of I in its low-energy MLCT band in the presence of PR3 or a N-donor ligand (L) causes photosubstitution of the last CO ligand of the Fe(1)-bipy moiety, giving the thermally unstable complex (II).Because of this thermal lability of the primary photoproduct, the photochemical reactions were performed in 2-Me-THF at 133 K.The complexes II with L=PR3 decomposed thermally above 200 K, but when L was an N-donor ligand, partial decomposition took place at 133 K.The nature of these decomposition products depend on L.It is suggested that the photochemical reactions occur from a reactive ³LF state after intersystem crossing from the ¹MLCT state.Evidence for a close lying ¹LF state comes from the resonance Raman spectrum upon 458 nm excitation, which shows anti-resonance Raman effects for all the vibrations.