A platinum-ruthenium dinuclear complex bridged by bis(terpyridyl)xanthene.

4,5-Bis(terpyridyl)-2,7-di-tert-butyl-9,9-dimethylxanthene (btpyxa) was prepared to serve as a new bridging ligand via Suzuki coupling of terpyridin-4'-yl triflate and 2,7-di-tert-butyl-9,9-dimethylxanthene-4,5-diboronic acid. The reaction of btpyxa with either 1 equiv or an excess of PtCl(2)(cod) (cod = 1,5-cyclooctadiene) followed by anion exchange afforded mono- and dinuclear platinum complexes (PtCl)(btpyxa) (1) and (PtCl)(2)(btpyxa)(2) (2(2)), respectively. The X-ray crystallography of 1.CHCl(3) revealed that the two terpyridine units in the ligand are nearly parallel to each other. The heterodinuclear complex (PtCl)Ru((t)Bu(2)SQ)(dmso)(2) (4(2)) (dmso = dimethyl sulfoxide; (t)Bu(2)SQ = 3,5-di-tert-butyl-1,2-benzosemiquinone) and the monoruthenium complex Ru((t)Bu(2)SQ)(dmso)(trpy) (5) (trpy = 2,2':6',2' '-terpyridine) were also synthesized. The CV of 2 suggests possible electronic interaction between the two Pt(trpy) groups, whereas such an electronic interaction was not suggested by the CV of 4 between Pt(trpy) and Ru((t)Bu(2)SQ) frameworks.