Heterobimetallic rollover derivatives

Heterobimetallic complexes with metal centers connected by a small delocalized ligand constitute an interesting class of compounds. Here we report that starting from the mononuclear platinum(II) rollover complexes [Pt(bipy-H)(L)Cl] (bipy-H = 2,2′-bipyridine C(3′)-N cyclometalated, L= DMSO, PPh 3) a second rollover cyclometalation may produce a series of Pt(II)/Pd(II) heterobimetallic complexes where the two metals are linked by the planar, highly delocalized, doubly deprotonated 2,2′-bipyridine