Neutral mononuclear and dinuclear complexes of gold(I) featuring azole ligands: Synthesis, structure and cytotoxicity

The aim of this work was to extend the small library of existing compounds of gold(I) that contain pentafluorophenyl and thiazole ligands and to determine the biological activity of such compounds against a well-known cancer cell line. Seven mono and dinuclear new compounds that contain imidazole, thiazole and tetrazole rings were isolated and characterised. Three of the crystal structures determined indicated Au…Au interactions between constituent complex molecules. A simple adduct, [Au(C6F5)(N-methyl-imidazole)], exhibits a relatively high anti-tumour specificity indicating the viability of selected phosphine-free gold complexes as cytotoxic agents.

Imidazole, thiazole and tetrazole derivatives readily coordinate to the neutral C6F5Au fragment by substitution of labile tetrahydrothiophene. The simple product derived from 1-methylimidazole exhibit higher cytotoxicity against HeLa cells than the tetrazole complex and than neutral azolato or cationic tetrazolylidene complexes that contain ancillary phosphine ligands.Figure optionsDownload as PowerPoint slideHighlights
► Isolation of new, neutral, azole-containing gold complexes.
► High yield synthetic procedures.
► Clear-cut physical characterisation and structure determination (Au…Au interactions).
► Structure determination of a unique tetrazole complex.
► Preliminary screening for anticancer activity against HeLa cells.