Oxyphosphoranes as precursors to bridging phosphate-catecholate ligands.

Examples of chelating ligands that incorporate P-O donors are seldom encountered. Herein, a series of novel bridging diphosphate ligand supported bimetallic Zr(iv), V(iii) and Ni(ii) complexes have been derived from reactions of the oxyphosphorane (C6Cl4O2)P(OEt)3 with the corresponding metal halides. The mechanism is probed and shown to involve elimination of ethyl halide, and ring opening affording the chelating phosphate-catecholate ligands.