A series of luminescent Cu(i) mixed-ligand complexes containing 2,9-dimethyl-1,10-phenanthroline and simple diphosphine ligands

Abstract

A series of Cu(I) mixed-ligand complexes containing dmp (2,9-dimethyl-1,10-phenanthroline) and one of simple diphosphine ligands (Ph₂P(CH₂)_nPPh₂) were prepared. Among the complexes, [Cu(dppp)(dmp)]PF₆ (n = 3) and [Cu₂(dppb)₂(dmp)₂](PF₆)₂ (n = 4) were characterized by X-ray structure analyses. The dppp complex has been characterized as a mononuclear complex, while [Cu₂(dppb)₂(dmp)₂]²⁺ exists as a dinuclear complex in which two dppb ligands bridge between the two Cu(I) atoms. Although the distorted tetrahedral structures around the central metals of the two complexes are similar, the P–Cu–P angles are different between the two complexes. All of the series of complexes show photoluminescence in solution, and the intensity of the luminescence increases with n (n = 2–4). The non-radiative rate constants of the complexes decrease markedly with n although radiative rate constants of the complexes are similar.