Experimental and Theoretical Study of Novel Luminescent Di-, Tri-, and Tetranuclear Copper Triazole Complexes

A number of novel luminescent di-, tri-, and tetranuclear copper complexes have been synthesized in good yields using a modular ligand system based on triazole-phosphines. This kind of ligand is easily accessible through an improved one-pot synthesis that permits the facile introduction of various alkyl or aromatic substituents at the 1-, 4-, or 5-position of the triazole ring. X-ray crystallography revealed three different types of complexes: neutral di- and tetranuclear structures with Ci symmetry, and a charged trinuclear structure posessing C3 symmetry. A spectroscopic evaluation showed promising photoluminescence properties in terms of their potential use in organic light-emitting devices, with maxima in the range of 500–550 nm, depending on the substitution pattern of the triazole ligand used for the complexation. Experimental observations were complemented by density functional theory calculations of ground and excited states.