WAVELENGTH DEPENDENCE OF PHOTOCATALYTIC CYCLOHEXANE DEHYDROGENATION BY CARBONYL-(CHLORO)PHOSPHINE AND THIOCARBONYL-(CHLORO)-PHOSPHINE RHODIUM(I) COMPLEXES

Photocatalytic dehydrogenation of cyclohexane using [RhCl(CS)(PPh3)2] was closely related to photodissociation of the CS ligand, where the effective absorption band was not of the lowest energy but the second lowest, in contrast to the CO analogue. The estimated turnover number of [RhCl(PPh3)2] in the dehydrogenation cycle was 3.8 on the assumption that [RhCl(CS)(PPh3)2] is photodecomposed irreversibly. The wavelength dependence of photocatalysis by these complexes is well interpreted in terms of the molecular-orbital energy levels and orbital interactions.