A novel technique to synthesize nanoparticles of titanium dioxide, cadmium sulfide, and silicon dioxide, capped with 2,2-bipyridine compounds

Abstract

The dynamics of electron transfer in the molecule–nanoparticle system and charge-transfer intramolecular complexes of TiO2, SiO2, and CdS were compared. Charge-transfer complexes and intramolecular charge-transfer complexes with superfast electron transfer–bipyridine–TiO2 and bipyridine–SiO2– were obtained. Both complexes are characterized by similar charge transfer bands and donor (bipyridine) and acceptor (Ti or Si) orbitals. The electron is localized on titanium or silicon sites in the metal–bipyridine complex but can be localized on the other Ti, Si, and CdS sites in TiO2 and SiO2 nanoparticles. The reverse dynamics of electron transfer from titanium sites to bipyridine ligands in the time interval of 200 fs is observed in the molecular complex. Titanium–cadmium–bipyridine (TCB) and silicon–cadmium–bipyridine (SCB) systems were synthesized and purified by two methods: Blodgett and sol–gel. The synthesized compound was identified by elemental analysis, X-ray powder diffractometry, infrared spectroscopy, scanning electron microscopy, and spectrophotometry in the ultraviolet and visible regions of the spectrum. The optical properties of the samples were investigated.