A homoleptic tris(diphosphacyclobutadiene) tripledecker sandwich complex

The synthesis and characterisation of [Co 2 (η 4 -P 2 C 2 t Bu 2 ) 2 (μ:η 4 :η 4 -P 2 C 2 t Bu 2 )] (1) is described, featuring two cobalt atoms and three diphosphacyclobutadiene ligands. This compound is the first triple-decker sandwich complex which exclusively contains cyclobutadiene ligands. The first tripledecker sandwich complex exclusively containing (diphospha)cyclobutadiene ligands was synthesised via an unexpected route and structurally characterised. An analysis of the bonding situation and redox behaviour is presented.