A series of new emissive mononuclear copper(I) bipyridyl complexes bearing the methoxycarbonyl groups

Abstract

A new series of mononuclear copper(I) complexes 1–3 possessing functionalized 6-methoxycarbonyl-2,2′-bipyridine and phosphine mixed ligands have been synthesized and characterized. Each Cu(I) atom gives an N2P2 distorted tetrahedral configuration, in which the dihedral angles between two pyridyl rings follow a ranking of 1 (4.640°)<2 (av. 9.065°)<3 (15.648°), while a reverse order lies in the dihedral angles between the methoxycarbonyl and its conjoined pyridyl ring (1 (15.224°)>2 (av. 8.983°)>3 (2.786°)). Complexes 1–3 show a weak low-energy absorption band at 330–500nm in CH2Cl2 solution, ascribed to charge-transfer transitions with appreciable 1MLCT character, as supported by TD-DFT calculations. The solid-state luminescence is observed in 1–3 at room temperature, which is affected by the phosphine, the substituents on the 2,2′-bipyridyl, and the above-mentioned dihedral angles.