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

The reaction of a square-planar platinum(II) complex containing two bis(2-diphenylphosphinoethyl)phenylphosphine (triphos), [Pt(triphos) 2 ](NO 3 ) 2 , with [Au(tu) 2 ]Cl (tu = thiourea) gave a new trinuclear Au I 2 Pt II complex, [Pt(triphos) 2 {Au(tu)} 2 ]Cl 2 (NO 3 ) 2 , through Au-P coordination. While the [Pt(triphos) 2 ] 2+ unit in [Pt(triphos) 2 ](NO 3 ) 2 adopted the trans-meso configuration, only the cis-racemic isomer was observed for [Pt(triphos) 2 {Au(tu)} 2 ]Cl 2 (NO 3 ) 2 . 31 P NMR spectroscopy indicated rapid equilibrium among the possible isomers of [Pt(triphos) 2 ] 2+ , which facilitated the trans-to-cis transformation at the Pt II center in this system. Additionally, we observed that this structural transformation led to an increase in the emission intensity.