Development of Visible Light-Driven Hybrid Catalysts Composed of Earth Abundant Metal Ion Modified TiO2 and B12 Complex
Keita Shichijo, Midori Watanabe, Yoshio Hisaeda, Hisashi Shimakoshi
Abstract
Abstract The development of highly-functional visible light-driven hybrid catalysts (B12-Mn+/TiO2) prepared from B12 complexes (B12) derived from natural vitamin B12, earth-abundant metal ions (Mn+), and titanium oxide (TiO2) was reported. The metal ions, such as Cu2+, Ni2+, Fe2+, Zn2+, Mn2+, Al3+, and Mg2+, were modified on the surface of TiO2 (2.4 × 10−5–9.9 × 10−5 mol/g) to obtain effective response to visible light, and the B12 complex was also loaded (6.2 × 10−6–1.1 × 10−5 mol/g) to produce a highly-functional hybrid catalyst. Amide formations from dichlorodiphenyltrichloroethane (DDT) catalyzed by the B12-Mn+/TiO2 proceeded in up to 89% yields in the presence of triethylamine (NEt3) under visible light irradiation (λ ≧ 420 nm) in air at room temperature. These hybrid catalysts could be classified into two groups based on these reactivities, and it was found that the B12-Mg2+/TiO2 showed the most effective catalytic activities of all the prepared samples. The B12-Mg2+/TiO2 also catalyzed the syntheses of fine chemicals, such as N,N-diethyl-3-methylbenzeamide (DEET), and N,N-diethylcyanoformamide, from the corresponding trichloromethyl compounds (FG-CCl3) with about 80% yields.