Chalcogenoacyl-bridged derivatives of the unsaturated carbyne complex [Mo2(η5-C5H5)2(μ-CPh)(μ-PCy2)(CO)2]

C−E coupling (E = S, Se) takes place in the reactions of the title benzylidyne-bridged complex with elemental chalcogens to give the corresponding chalcogenoacyl-bridged derivatives, which can be isomerized photochemically with little perturbation of the bridging ligand, specifically placed with the chalcogen atom trans to P.107