Dinuclear gold(i) complexes with pyrimidine- and m-carborane-based bisphosphine ligands: synthesis, structure, photoluminescence and cytotoxicity against malignant pleural mesothelioma

Dinuclear Au(I) complexes with bisphosphine ligands, namely [Au2Cl2(L)], where L = 4,6-bis(diphenylphosphino)pyrimidine (Au1) or 1,7-bis(di-o-tolylphosphinyl)-m-carborane (Au2), have been synthesized. The complexes were characterized by analytical and spectroscopic methods and their crystal structures were determined by X-ray diffraction analysis. Both complexes demonstrated photoluminescence in the solid state at 300 K when excited at 300–400 nm: from blue emission (∼400 nm) for Au1 to green emission (∼500 mn) for Au2. The lifetimes of the excited state were determined to be in the microsecond range, indicating the triplet nature of the emission levels. Preliminary bioactivity tests for complexes Au1 and Au2 in comparison with the respective ligands and cisplatin have been performed.