Synthesis and structure of the cyclometalated hetero-binuclear Pt-Au complexes with bridging 2-diphenylphosphinopyridine ligand

•Heterobinuclear cyclometalated platinum(II)-gold(I) complexes have been synthesized.•Structure of these complexes characterized in solid state and solution. They show Pt–Au dative bonds.•Absorption spectra of these complexes obtained and their transitions assigned using DFT and TD-DFT calculations.

The heterobinuclear cyclometalated PtII-AuI complexes of the type [MePt(bhq)(μ-dppy)AuL]PF6, in which, bhq = benzo{h}quinoline, dppy = 2-diphenylphosphinopyridine, L = PPh3, 5; PPh2Me, 6; PPhMe2, 7; have been prepared by reaction of the mononuclear platinum(II) complex [MePt(bhq)(dppy)], 1, with 1 equiv. [AuL]+. Also, the reaction of complex 1 with 1 equiv AuCl(SMe2) at −60 °C gave the neutral heterobinuclear complex [MePt(bhq)(μ-dppy)AuCl], 8. All of the complexes were characterized using NMR spectroscopy and elemental microanalysis and complexes 5 and 8 were further identified by single crystal X-ray structure determination. Time-dependent density functional theory (TD-DFT) is used to elucidate the origin of the electronic transitions in the heteronuclear complexes5 and 8. The low energy absorptions for the heterobinuclear complex 5 are attributed to an admixture of ligand-to-ligand charge transfer (1LL′CT) and metal-to-ligand charge transfer character (1MLCT).

Graphical abstractNeutral and cationic heterobinuclear cyclometalated platinum(II)-gold(I) complexes containing bridging bis(diphenylphosphino)pyridine(dppy) ligand have been prepared and their structures characterized. These complexes show swapping of dppy ligand.Figure optionsDownload full-size imageDownload as PowerPoint slide