Mono‐ and tetranuclear copper(I) complexes with N‐heterocyclic chelating and triphenylphosphine ligands: Crystal structures, luminescent and heterogeneous catalytic properties

Abstract

N‐heterocyclic chelating and triphenylphosphine ligands react with cuprous halide to form a variety of copper(I) complexes, namely, mononuclear [Cu(PBO)(PPh3)Br].CH2Cl2 (1) and [Cu(PBM)(PPh3)I] (2) (PBO = 2‐(2′‐Pyridyl)benzoxazole, PBM = 2‐(2′‐Pyridyl)benzimidazole, PPh3 = triphenylphosphine) and tetranuclear [Cu4(μ2‐I)2(μ3‐I)2(PPh3)4].2CH2Cl2 (3) have been synthesized and characterized. Complexes 1 and 2 are basically alike; both of them are mononuclear and four‐coordinated, possessing a slightly distorted trigonal pyramidal geometry. Complex 3 is tetranuclear and the coordination numbers of the two copper(I) atoms are three and four, Cu(1) forming an approximate trigonal planar coordination environment, while Cu(2) is a slightly distorted trigonal pyramidal geometry, resulting in a distorted chair‐like conformation. Complexes 1 and 2 are emissive in the solid state at ambient temperature, with the maxima at 552 and 602 nm, respectively, due to a MLCT excited state. Moreover, complex 3 manifests promising heterogeneous catalytic activities for the degradation of methylene blue (MB), with degradation efficiency of 99% under ambient light.