Catalytic synthesis and characterization of aryl benzimidazole and its interaction with TiO2 nanoparticles: ESIPT process

Abstract

2-(1-phenyl-1H-benzo[d]imidazol-2-yl)-4-(trifluoromethyl)phenol(PBITP) has been synthesised and the compound structure was confirmed by proton NMR, carbon NMR, mass spectral studies and elemental analysis. The binding interaction between PBITP and different phases of TiO2 nanoparticles were investigated. We have observed surprising result. Synthesized PBITP enhanced the fluorescence of rutile phase of TiO2 on account of the lowering of frontier orbital levels of the PBITP. But the opposite trend was observed for anatase phase of TiO2. So that, we can identify the rutile and anatase phase. The mechanism of electron transfer was discussed in detail. Emission spectroscopy has been employed to probe on the process of excited state intra-molecular proton transfer (ESIPT) in hydroxy imidazole.An abnormal Stokes – shifted emission band, at shorter and longer wavelengths has been observed in the fluorescence spectra of the sample PBITP / dioxane, which is an indication towards the existence of two different forms of intra-molecular hydrogen bonded isomers.

Keywords

• Fluorescence
• Sensor
• TiO2 nanoparticles
• ESIPT