Niederkoordinierte phosphorverbindungen: XXXXIII. Methylenphosphane und phosphinomethylenphosphane als η2-liganden in nickel(0)-ko]mplexen

The complex (η²-ClPCTms₂)₂NiCO (II) has been prepared and its structure was determinated by X-ray analysis. With Ni(CO)₄ the 1,2-diphosphapropenes (IVa,b) form the η¹ complexes (Va,b), which could be identified by NMR spectroscopy. At room temperature Va,b dimerize to the novel complexes VIa,b, in which the phosphine atom of IVa,b acts as a η¹ and the PC bond as a η² ligand towards the Ni atom. The structure of VIa was also determinated by X-ray analysis.