Photo-induced ring-expansion reactions mediated by B12-TiO 2 hybrid catalyst

Shin Ichiro Izumi, Hisashi Shimakoshi, Masaaki Abe, Yoshio Hisaeda

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20 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)3302-3307
Number of pages6
JournalDalton Transactions
Issue number13
Publication statusPublished - Mar 23 2010

All Science Journal Classification (ASJC) codes

  • Inorganic Chemistry

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