Intramolecularly coordinated azobenzene selenium derivatives: Effect of strength of the Se center dot center dot center dot N intramolecular interaction on luminescence

A series of selenium derivatives (6-12) of 2-phenylazophenyl have been synthesized using o-lithiation route. The effect of the strength of the intramolecular Se center dot center dot center dot N interaction on the absorption spectra as well as emission spectra has been studied. The studies suggest that the secondary bonding Se center dot center dot center dot N interaction give rise to fluorescence, however, the strength of Se center dot center dot center dot N interaction cannot be directly correlated with the intensity of the fluorescence. TD-DFT calculations show that the main transition involved in the absorption spectra of the compound is the ligand based pi-pi* type.