Aurophilicity in gold(i) thiosemicarbazone clusters

Abstract

The reaction of the phosphine thiosemicarbazone ligands HLPH and HLPMe with Au(I) ions yields the gold complexes [Au₃(HLPH)₂Cl₂]Cl·2MeOH (1·2MeOH) and [Au₂(HLPMe)Cl₂] (2). The structures determined by X Ray diffraction, [Au₃(HLPH)₂Cl₂]Cl·4MeOH (1·4MeOH) and [Au₂(HLPMe)Cl₂]₂ (2), are the first examples of gold(I) thiosemicarbazone clusters showing aurophilicity. The structure of the trinuclear cation 1 contains the Au(1) atom located in an inversion centre, being connected to another gold(I) atom, Au(2), through a phosphino thiosemicarbazone molecule which acts as a S,P-bridging ligand. Additionally, every gold(I) atom in the trinuclear cation 1 assembles into trinuclear linear cluster units by means of close gold–gold interactions, being connected through the crystal cell in a 2D zigzag mode. The crystal structure of [Au₂(HLPMe)Cl₂]₂ (2) contains one discrete molecule [(AuCl)₂(HLPMe)] in the asymmetric unit, which is further assembled into tetranuclear [(AuCl)₂(HLPMe)]₂ units by means of close gold–gold interactions. Both clusters are highly luminescent in solution.