Facial synthetic method of 4,7-position conjugation extended phenanthrolines and X-ray structure of copper phosphine phenanthroline complexe were reported. The crystal structures showed π-stacking and hydrogen bonding, and a small torsional angle between phen and phenylacetylene. These complexes exhibited strong conjugation dependant MLCT luminescence. The electronic and fluorescence spectra displayed a gradual red shift of the MLCT band as the conjugation increased. The presence of the phenyl groups reduced the energy of the π∞ state in the d-π∞ MLCT transition, allowing for the red shift. The electron-donating tri-isopropylsilyl (TIPS) groups on the ethynyl moiety increased the energy of the MLCT charge vector, allowing for the blue shift at the luminescence.
- Copper complex
- Mixed ligand diimine complex