Interaction of bioactive molecule with surfaces of nanoscale transition metal oxides: experimental and theoretical studies
We report a detailed experimental and theoretical investigations on interaction between bioactive benzthiazoline-2-thione (BTT) molecule and metal oxide surfaces suspended in aqueous solution. The metal oxides in their nanostructured form were synthesized through sol-gel synthesis. The interactions of BTT with α-Fe2O3 and NiO oxides surfaces were probed through spectroscopic signatures with the suspension of nanoparticles in aqueous medium. The spectral change of BTT between its free state and in bound state onto the suspended metal oxides surfaces in aqueous solution attests the signature of significant interactions. BTT spectra exhibit a hypsochromic shift of about 4-7 nm when it is attached to both the α-Fe2O3 and NiO oxides surfaces. Density functional theory (DFT) calculations reveal that charge transfer takes place from BTT through p-orbital of exocyclic sulphur atom to the O-p dominated conduction band of α-Fe2O3 (O-terminated) and to the Ni-3d dominated valence band of NiO surfaces. Such extension of charges from BTT to metal oxide surfaces is attributed to the origin of hypsochromic shift in UV-Vis spectra of BTT molecule.