PHOTOCHEMICAL-REACTIONS OF SEVERAL ADDUCTS OF METALLADITHIOLENES AND METALLADITHIAZOLES - DISSOCIATION AND REARRANGEMENT

The addition products of metalladithiolene and metalladithiazole complexes undergo interesting photochemical dissociation reactions accompanied by rearrangement. Three examples are discussed. Upon irradiation with a medium pressure mercury lamp, the quadicyclane adducts of cobaltadithiolene and rhodiadithiolene dissociate to the free metalladithiolenes and norbornadiene accompanied by the skeletal rearrangement in the hydrocarbon moieties. The tributylphosphine adduct of a cobaltadithiolene eliminates photochemically the coodinated phosphine via the attack of singlet oxygen. In the photoreaction with 254 nm light, the phosphine adduct itself acts as a triplet sensitizer to produce singlet oxygen. The DMAD adducts of 1,2,5-cobaltadithiolene and 1,2,5,3-cobaltadithiazole behave differently upon irradiation: DMAD adduct of the cobaltadithiolene eliminates selectively the alkyne moiety which bridges between Co and S, while DMAD adduct of the cobaltadithiazole eliminates carbonitrile to give the cobaltadithiolenes.