Synthesis, structures, luminescence and terahertz time-domain spectroscopy of nine Cu(I) complexes with PAP ligands and 1,10-phenanthroline derivatives

Nine new copper(I) complexes bearing 1,3-bis(diphenylphosphino)propane (dppp) and 4,7-diphenyl-1,10-phenanthroline (batho) or 2,9-dimethyl-1,10-phenanthroline (neo) have been synthesized and characterized. Single crystal X-ray diffraction analysis reveals that complexes 1-4 and 6-9 are mononuclear with similar structures, while complex 5 is a binuclear structure. They display absorption around 280 nm and 410 nm, and the intensive emission in the range of 520-620 nm in the solid state occurring with lifetimes on the mu s timescale indicates phosphorescence. Our TD-DFT calculations show that emission from the lowest excited triplet state T-1 is of (MLCT)-M-3 nature. This study manifests that these simple and long lifetime Cu(I) systems may exhibit a similar, but more complex excited state behavior than the systems previously appreciated. (C) 2018 Elsevier Ltd. All rights reserved.