Dinuclear C,N,C cyclometalated platinum derivatives with bridging delocalized ligands. Fourfold deprotonation of 6,6 '-diphenyl-2,2 '-bipyridine, H4L, promoted by "Pt(R)(2)" fragments (R = Me, Ph). Crystal structures of [Pt-2(L)(3,5-Me(2)py)(2)] and {Pt-2(L)(dppe)}(2) (dppe=1,2-bis(diphenylphosphino)ethane). X-ray powder diffraction of [Pt-2(L)(CO)(2)]

cis-[Pt(R)2(DMSO)2] (R = Me, Ph) reacts with 6,6'-diphenyl-2,2'-bipyridine (H4L) in a 2:1 molar ratio, giving the unusual, very slightly soluble dinuclear complex [Pt2(L)(DMSO)2] (1). The reaction implies activation of four C-H bonds: in 1 a fourfold deprotonated H4L links two Pt-DMSO fragments acting as a delocalized C,N,C^C,N,C 12-electron donor. From 1 more soluble dinuclear [Pt2(L)(L')2] (L' = bulky 2-electron donors such as PR3 and substituted pyridines) species, 2-6, and polynuclear {Pt2(L)(L-L)}n (L-L ) Ph2P(CH2)xPPh2 (x = 1, dppm; x = 2, dppe; x = 3, dppp)) species, 7-9, have been obtained by substitution of the DMSO ligands. DMSO can also be displaced from 1 by CO, both in solution and in the solid state, to give the flat and completely insoluble complex [Pt2(L)(CO)2] (10). The structures of [Pt2(L)(3,5-Me2-Py)2] (5) and {Pt2(L)(dppe)}2 (8) have been determined by single crystal X-ray diffraction analysis, while a powder X-ray diffraction analysis has been performed on complex 10, [Pt2(L)(CO)2]. With a 1:1 Pt:L molar ratio a mononuclear complex, [Pt(H2L)(DMSO)] (11), is obtained, where the twofold deprotonated ligand is C,N,C coordinated. Also, the DMSO can be displaced from 11 by neutral ligands, L', such as CO, PPh3, and 3,5-Me2-py to give [Pt(H2L)(L')] (12-14). Compounds 11-14 further react with cis-[Pt(R)2(DMSO)2] to give dinuclear complexes. This two-step approach allows us to obtain species with different ligands around each platinum atom, [Pt2(L)(L')(L'')] (15-18).