Site Specific Interaction Between TiO2 Nanoparticles and Phenanthrimidazole-A First Principles Quantum Mechanical Study.

Understanding the interaction between the nanomaterials and bioactive molecules are of current interest due to the potential application of nanomaterial in biomedical field. The structural, electronic and optical properties of newly synthesised fluorophore 2-(4-methoxynaphthalen-1-yl)-1-phenyl-1H-phenanthro[9.10-d]imidazole have been investigated in detail. The imidazole absorbs strongly on the surface of TiO2 nanocrystals probably because of the chemical affinity of azomethine nitrogen atom of the imidazole, resulting in lowering the HOMO and LUMO energy levels. The TEM, SEM and EDX spectra confirm the adsorption of imidazole on the surface of TiO2 nanocrystals. The growth behavior and stability of small stoichiometric (TiO2)n clusters have been analysed by using density functional theory which reveals that clusters prefers three-dimensional structures. In addition, the interaction between the ground state structure of the (TiO2)n cluster and a single imidazole molecule have been studied. The calculated binding energy (Eb) and the energy gap (Eg) indicate that the imidazole molecule preferably binds to the Ti atom of the (TiO2)n clusters through its azomethine nitrogen atom; the binding energy is in range 5.24-7.89 eV. In order to understand the binding interaction with DNA docking study has been carried out.