Gold(I) coordination compounds with mesoionic thiolate ligands and the crystal and molecular structure of bis(1,4,5-trimethyl-1,2,4-triazolium-3-thiolate)gold(I) tetrafluoroborate

Two-coordinate gold(I) complexes involving mesoionic thiolate ligands have been synthesized, including homoleptic and mixed-ligand complexes. Many of these compounds have stability and solubility properties that are desirable for practical use as gold sensitizers for photographic silver halide dispersions. The crystal structure of bis(1,4,5-trimethyl-1,2,4-triazolium-3-thiolate)gold(I) tetrafluoroborate has been solved by single-crystal X-ray diffraction. Several structural parameters support the view that the mesoionic ligands possess substantial thiolate character as a result of the unusual conjugation present in these heterocyclic compounds.