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Visible‐light‐driven organic synthesis is a green and sustainable method for producing fine chemicals and is highly desirable at both laboratory and industrial scales. In this study, we developed a broad‐range (including the red region) visible‐light‐driven carbonylation of CCl4, CBr4, and CBr3F with nucleophiles, such as amines and alcohols, using a B12−Mg2+/TiO2 hybrid catalyst. Carbonyl molecules such as ureas, carbamates, carbonate esters, and carbamoyl fluorides were synthesized with high selectivity and efficiency under mild conditions. Diffuse reflectance UV‐vis spectroscopy, femtosecond time‐resolved diffuse reflectance spectroscopy, and density functional theory calculations revealed the reaction mechanism is a combination of SN2 and single‐electron transfer. This is a rare example of a low‐energy, red‐light‐driven photocatalysis, which has been a highly desired organic reaction in recent years. We believe that this study provides a general platform to access diverse carbonyl molecules and could promote photocatalytic carbonylation reactions on a pilot scale. [ABSTRACT FROM AUTHOR]

This concept focuses on dual‐catalysis using metal complexes and heterogeneous photocatalysts. Vitamin B12 derivatives are sophisticated metal complexes that facilitate enzymatic reactions in the biological systems. The B12 enzymes inspired reactions catalytically proceed in dual‐catalyst systems of B12 derivatives and heterogeneous photocatalysts, such as titanium oxide (TiO2) and metal‐organic frameworks (MOFs), under light irradiation. The cobalt ions in B12 derivatives are effectively reduced by photoexcited photocatalysts, producing low‐valent Co(I) species. The photoinduced nucleophilic Co(I) species react with an alkyl halide to form an organometallic complex with a Co−C bond. The Co−C bond dissociates during photolysis to generate alkyl radicals. Based on this mechanism, dual‐catalysis effectively promotes various light‐driven organic syntheses and light‐driven dehalogenation reactions of toxic alkyl halides. The trends of the dual‐catalyst system and recent progress in this field are discussed in this concept. [ABSTRACT FROM AUTHOR]

A B12 complex–BODIPY dyad was synthesized by peripheral modification of cobalamin derivatives. The photophysical properties of the dyad were investigated by UV-vis, PL, and transient absorption spectroscopy. A visible light-driven dechlorination reaction of a trichlorinated organic compound, DDT, was reported. The dyad showed efficient catalysis for dechlorination under N2 with turnover numbers of over 220 for the reaction. One-pot syntheses of an ester and amide from DDT and benzotrichloride were also achieved using the dyad under air. [ABSTRACT FROM AUTHOR]

This concept focuses on dual-catalysis using metal complexes and heterogeneous photocatalysts. Vitamin B 12 derivatives are sophisticated metal complexes that facilitate enzymatic reactions in the biological systems. The B 12 enzymes inspired reactions catalytically proceed in dual-catalyst systems of B 12 derivatives and heterogeneous photocatalysts, such as titanium oxide (TiO 2 ) and metal-organic frameworks (MOFs), under light irradiation. The cobalt ions in B 12 derivatives are effectively reduced by photoexcited photocatalysts, producing low-valent Co(I) species. The photoinduced nucleophilic Co(I) species react with an alkyl halide to form an organometallic complex with a Co-C bond. The Co-C bond dissociates during photolysis to generate alkyl radicals. Based on this mechanism, dual-catalysis effectively promotes various light-driven organic syntheses and light-driven dehalogenation reactions of toxic alkyl halides. The trends of the dual-catalyst system and recent progress in this field are discussed in this concept., (© 2024 The Authors. ChemPlusChem published by Wiley-VCH GmbH.)

A B 12 complex-BODIPY dyad was synthesized by peripheral modification of cobalamin derivatives. The photophysical properties of the dyad were investigated by UV-vis, PL, and transient absorption spectroscopy. A visible light-driven dechlorination reaction of a trichlorinated organic compound, DDT, was reported. The dyad showed efficient catalysis for dechlorination under N 2 with turnover numbers of over 220 for the reaction. One-pot syntheses of an ester and amide from DDT and benzotrichloride were also achieved using the dyad under air.