Unusual Coordination Assemblies from Platinum(II) Thienyl and Bithienyl Complexes

Dinuclear Pt2Br2(dppf)2((mu)-C8H4S2) exchanges with isonicotinic acid to release free bithiophene and gives a molecular square [Pt4 (dppf)4((mu)2-O2CC5H4N)4]4+4OTf- which is an "all-ring" system with four Pt rings disposed at the corners of a larger macrocyclic ring. The related mononuclear complex PtBr( 1(C2)-C4H3S)(dppf) reacts with AgOTf (OTf = triflate) to give [Pt2(dppf)2((mu)2,(eta)^1(C), (eta)^1(S)-C4H3S)2]2+2OTf- with an unusual six-membered ring formed by the fusion of two Pt-thienyl entities at the sulfur sites. All the complexes are structurally characterized by single-crystal X-ray crystallography.