Rational creation of chiral multinuclear and metallosupramolecular compounds from thiol-containing amino acids

Abstract

Developments in the rational creation of chiral multinuclear and metallosupramolecular compounds based on linear-type metal complexes with penicillaminate (pen), as well as their functionality as a multidentate chiral metalloligand, is the main subject of this paper. The reactions of a mononuclear Au^I complex, [Au(D-pen)₂]³⁻, in which two D-pen ligands bind to an Au^I center through thiolato S atoms, with transition metal ions afford a variety of S-bridged heterobimetallic multinuclear complexes, the structures and properties of which are highly dependent on the nature of reacting metal ions. The created multinuclear complexes still act as a metalloligand when they possess free amine and/or carboxylate groups, leading to the formation of heterotrimetallic supramolecular structures by reacting with third metal ions. While the Au–S bonds in [Au(D-pen)₂]³⁻ are generally retained in the course of the reactions with metal ions, this is not the case for the Hg–S bonds in the corresponding Hg^II complex, [Hg(D-pen)₂]²⁻. A remarkable chiral behavior of multinuclear complexes composed of [Au(L-cys)₂]³⁻ (cys = cysteinate), which is opposite to that composed of [Au(L-pen)₂]³⁻, is also presented.