Oxonium-ion crown ether complexes from aqua regia

Abstract

Reaction of an aqua regia solution of gold metal with 15-crown-5 and its derivatives results in the formation of the hydrogen bonded aggregates [H₇O₃][AuCl₄]·15-crown-5 1 and [H₅O₂][AuCl₄]·(benzo-15-crown-5)₂ 2; complex 1 exhibits a complex, cross-linked structure in which the H₇O₃⁺ unit hydrogen bonds to two adjacent crown ethers and a chloride ligand of the anion; the Au^III centre also engages in long-range interactions wtih the crown oxygen atoms.