Luminescent Properties Of Some Imidazole And Oxazole Based Heterocycles Synthesis, Structure And Substituent Effects

A series of 2-R-6-(aryloxazol-/imidazol-2-yl)pyridine and 2 4-di-tert-butyl-6-(1H-phenanthro[9 10-d] imidazol-/oxazol-2-yl)phenol derivatives were synthesized and characterized using elemental and spectroscopic analyses as well as single-crystal X-ray diffraction analysis The oxazole derivatives displayed higher photoluminescence efficiencies than their imidazole analogues The 2-(phenanthro[9 10-d]oxazole/imidazol-2-yl)pyridine derivatives displayed quantum yields approaching unity in non-polar solvents but were quenched in polar solvents The oxazole analogues produced reversible fluorescence photoswitching between 400 nm and 550 nm regions whilst the imidazole analogues underwent an irreversible photo-induced excimer formation in polar solvents H-1 NMR was used to rationalize the proposed mode of intermolecular interactions between excimers of the 2-(phenanthro[9 10-d]imidazol-2-yl)pyridine derivatives (C) 2010 Elsevier Ltd All rights reserved