Cyclometalated alkynylgold(III) complexes of 2-phenylpyridine and 2-(p-tolyl)-pyridine – Synthesis, photophysical and electroluminescence properties

Two cyclometalated alkynylgold(III) complexes [AuCl(tpy)(C≡C–C6H4CH3)] (1) and [AuCl(ppy)(C≡C–C6H4CH3)] (2), where ppy = 2-phenylpyridine and tpy = 2-(p-tolyl)-pyridine, were successfully synthetized. Their photophysical properties were investigated by absorption and photoluminescence spectroscopy in solution, solid state, and glass matrix (77 K). Differences in solid state luminescent behaviour of the reported Au(III) complexes were correlated with packing of [AuCl(tpy)(C≡C–C6H4CH3)] and [AuCl(ppy)(C≡C–C6H4CH3)] molecules and weak interactions in the network lattices of 1 and 2. Additionally, photoluminescence spectra of [AuCl(tpy)(C≡C–C6H4CH3)] in film and dispersed in solid matrix consisting of poly(9-vinylcarbazole) and (2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole) were registered. The preliminary tests of electroluminescence ability of complex 1 were carried out.