Metal-mediated C–C bond formation in a platinum(II)-coordinated dipyridylmethane ligand: an unusual example of “ipso-coupling” with solvent involvement

We report the chelation-assisted oxidative CH2extrusion from a PtII-coordinated dipyridylmethane, resulting in the formation of a 2,2′-bipyridyl ligand. This unusual one-pot reaction (solvent: dimethylformamide, DMF), which is quantitative, proceeds in air at mildly elevated temperature, with CH2→ C=O conversion, decarbonylation, and ipso-ipsoC–C coupling of the two pyridyl residues (“fragment coupling”). It constitutes, in effect, a chelate ring contraction by one member.