Visible light-driven photocatalytic duet reaction catalyzed by the B12-rhodium-titanium oxide hybrid catalyst.

The hybrid catalyst composed of the B 12 complex and rhodium ion (Rh3+) modified titanium oxide was synthesized for the visible light-driven B 12 inspired catalytic reaction. The hybrid catalyst contains 4.93 × 10−6 molg−1 of the B 12 complex and 5.43 × 10−5 molg−1 of the Rh(III) ion on the surface of titanium oxide. Visible light irradiation (λ ≧ 420 nm) of the hybrid catalyst in the presence of triethylamine (Et 3 N) as a sacrificial reagent showed absorption at 390 nm, typical for the Co(I) state of the B 12 complex monitored by diffuse reflectance UV–vis analysis, which imply that electron transfer from the titanium oxide to Co(III) center of the B 12 complex occurred by the visible light irradiation. Benzotrichloride was converted to N , N -diethylbenzamide by the visible light irradiation catalyzed by the hybrid catalyst in air at room temperature. Both the conduction band electron and valence band hole of the catalyst were utilized for the reaction to form the amide product. The reaction mechanism of the duet reaction was proposed. Image 1 • The hybrid catalyst composed of the B 12 complex, rhodium (III) ion, and TiO 2 was synthesized. • Various amides were formed from the benzotrichloride derivative by the B 12 modified visible light-driven photocatalyst under mild conditions. [ABSTRACT FROM AUTHOR]