Photophysical and excited-state intramolecular proton transfer of 2-(1-(3,5-dimethylphenyl)-1H-phenanthro[9,10-d] imidazol-2-yl)phenol: DFT analysis

Fluorescent phenenthrimidazole derivatives have been synthesized and characterized by H-1, C-13 NMR and mass spectral analyses. Synthesized compounds have been. The solvent effect on the absorption and fluorescence bands has been analyzed and supplement by computational studies. Phenenthrimidazole containing hydroxy group shows a single prominent absorption and emission in polar solvents and dual emission in non-polar solvents due to excited state intramolecular proton transfer (ESIPT). The ESIPT of 2-(1-(3,5-dimethylphenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenol was cross validated by the analysis of optimized geometry parameters, potential energy surface (PES), mulliken's charge distribution on the heavy atoms and molecular orbitals of its tautomers. Nonviability of ground state electron transfer was explained by HOMO-LUMO analysis. The intramolecular hydrogen bonding (IMHB) interaction has been explored by the calculation of electron density rho(r) and the Laplacian Delta(2)rho(r) at the bond critical point (BCP) using atoms-in-molecule (AIM) method and by calculation of hyper conjugative interaction between N-17 lone pair and sigma*(O-53 center dot center dot center dot H-54) using natural bond orbital (NBO) analysis. (C) 2014 Elsevier B.V. All rights reserved.