Trans-to-cis isomerization of a platinum(II) complex with two triphosphine ligands via coordination with gold(I) ions

Abstract

The reaction of a square-planar platinum(II) complex containing two bis(2-diphenylphosphinoethyl)phenylphosphine (triphos), [Pt(triphos)2](NO3)2, with [Au(tu)2]Cl (tu = thiourea) gave a new trinuclear AuI2PtII complex, [Pt(triphos)2{Au(tu)}2]Cl2(NO3)2, through Au-P coordination. While the [Pt(triphos)2]2+ unit in [Pt(triphos)2](NO3)2 adopted the trans-meso configuration, only the cis-racemic isomer was observed for [Pt(triphos)2{Au(tu)}2]Cl2(NO3)2. 31P NMR spectroscopy indicated rapid equilibrium among the possible isomers of [Pt(triphos)2]2+, which facilitated the trans-to-cis transformation at the PtII center in this system. Additionally, we observed that this structural transformation led to an increase in the emission intensity.