The First Water-Soluble Hexarhenium Cluster Complexes with a Heterocyclic Ligand Environment: Synthesis, Luminescence, and Biological Properties

The hexarhenium duster complexes with benzotriazolate apical ligands [{Re-6(mu(3)-Q)(8)}(BTA)(6)](4-) (Q = S, Se; BTA = benzotriazolate ion) were obtained by the reaction of [{Re-6(mu(3)Q)(8)}(OH)(6)](4-) with molten 1H-BTA (1H-benzotriazole). The clusters were crystallized as potassium salts and characterized by X-ray single-crystal diffraction, elemental analyses, and UV vis and luminescence spectroscopy. In addition, their cellular uptake and toxicity were evaluated. It was found that both clusters exhibited luminescence with high lifetimes and quantum yield values; they were taken up by the cells illuminating them under UV irradiation and, at the same time, did not exhibit acute cytotoxic effects.