Mononuclear Copper(I) complexes based on phenanthroline derivatives P^N^N^P tetradentate ligands: Syntheses, crystal structure, photochemical properties

Two novel heteroleptic Cu(I) complexes with the single tetradentate ligands have been designed and synthesized from phenanthroline. The complexes having one copper structure were fully characterized by NMR, ESI-MS and the single-crystal X-ray structures. Their photoelectric chemical properties were investigated by using cyclic voltammetry, UV/vis and fluorescence spectroscopy. Compared with the classic Cu(P^P)(N^N) complexes, this distorted tetrahedral coordination structure of Cu(P^N^N^P) complexes showed a wider excitation wavelength and a red-shifted about 100 nm emission peak, due to the link function between phenanthroline and phosphorus ligands. Moreover, the copper complex B having the naphthyl link groups displayed high red-emissive photoluminescence quantum efficiency (PLQY), which was up to 3.8%.