Synthesis and molecular structure of [Au4Cl8], and the isolation of [Pt(CO)Cl5]– in thionyl chloride

Abstract

A high-yield synthesis of [Au₄Cl₈] by treatment of [Au₂Cl₆] with the stoicheiometric amount of CO in COCl₂ is described. The crystal and molecular structure of the tetranuclear compound has been solved by X-ray diffraction methods. It is triclinic, space group P, with a = 7.015(4), b= 6.830(2), c= 6.684(4)Å, α= 94.4(1), β= 107.5(1), γ= 88.4(1)°, and Z= 1, and has been refined to R= 0.11 for 989 ‘ observed ’ reflections. The structure consists of discrete [Au₄Cl₈] molecules with square-planar gold(III) and almost linear gold(I) centres in a chair-like arrangement. The solid compound has a high reactivity towards CO. The platinum(IV) derivative [Pt(CO)Cl₅]^– has been isolated in SOCl₂ from the reaction of [Pt(CO)Cl₃]^– with chlorine.