Intramolecular phosphorus-phosphorus bond formation within a Co2P4 core.

The reduction of [(Cp‴Co)2(μ,η2:2-P2)2] (Cp‴ = 1,2,4-tBu3C5H2) with the samarocenes, [(C5Me4R)2Sm(THF)n] (R = Me or n-propyl), gives [(Cp‴Co)2P4Sm(C5Me4R)2]. This is the first example of an intramolecular P–P coupling in a polyphosphide complex upon reduction of the transition metal. The formation of the P–P bond is not a result of the direct reduction of the phosphorus atoms but is induced by a rearrangement of the positive charges between the metal atoms.