Vitamin B12-TiO2 heterogeneous hybrid catalyst (B12-TiO2) mediated ring-expansion reactions and their reaction mechanism were clarified by various spectroscopic methods. Diffuse reflectance UV/VIS (DR-UV/VIS) studies showed that B12-TiO 2 was activated to form the supernucleophilic Co(i) species of B 12 by irradiation with ultraviolet light. DR-UV/VIS and electron spin resonance (ESR) studies then elucidated the formation of the photo-sensitive intermediate on heterogeneous surfaces. The photo-excited B12- TiO2 catalyzed ring-expansion reactions were efficient and eco-friendly. This catalytic efficiency was strongly dependent on the kind of solvent. The oxidation reaction of the solvent by holes at TiO2 nanoparticle surfaces had a crucial role in the overall catalytic reaction.
All Science Journal Classification (ASJC) codes
- Inorganic Chemistry