Synthesis, crystal structures and photophysical properties of novel copper(I) complexes with 4-diphenylphosphino-1,5-naphthyridine ligands

Abstract: Two new copper(I) complexes [Cu(L 1 )2]PF6 (L 1 =4-diphenylphosphino-1,5-naphthyridine, 1) and [Cu(L 2 )2]PF6 (L 2 =4-diphenylphosphino-8-methyl-1,5-naphthyridine, 2), have been prepared and characterized. In each of them, the coordinate geometry of Cu atom is a distorted square planar configuration with bond distances and angles in the normal range. Moreover, compound 2 features one-dimensional zigzag chains which are cross-linked by the metal complex cations and PF6 − anions through hydrogen bonding interactions. The HOMO–LUMO energy gaps of 1–2 estimated by the cyclic voltammetry (CV) show values in the order of 1 > 2. Both 1 and 2 show low-energy bands ranging from 360 to 430nm and available florescence in the solid state at room temperature with λmax =532–541nm. The UV–vis absorption spectra of 1–2 show obvious red-shifts compared with those of the corresponding quinoline containing Cu(I) complexes [Cu(QN)2]PF6 (QN=8-diphenylphosphino quinoline), exhibiting the HOMO–LUMO energy gaps of 1–2 should be narrower than that of [Cu(QN)2]PF6. [Copyright &y& Elsevier]