Development of Visible Light-Driven Hybrid Catalysts Composed of Earth Abundant Metal Ion Modified TiO₂ and B₁₂ Complex

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 × 10¹⁵9.9 × 10¹⁵ mol/g) to obtain effective response to visible light, and the B₁₂ complex was also loaded (6.2 × 10¹⁶1.1 × 10¹⁵ 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 ½ 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.