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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]

(mu-Oxo)bis(mu-acetato)diiron(III) complexes, which exhibit kinetic and thermodynamic stability, are achieved first by synthesizing the novel ligand 1,2-bis(2- bis 2-pyridyl methyl -6-pyridyl)ethane. The ligand is produced upon a carbon-carbon homo-coupling of a carbanion of 2-(bis(2-pyridyl)methyl)-6-methylpyridine. The starting ligand, in turn, is formed by the reaction of a carbanion of 2,6-lutidine with 2-bromopyridine. Spectroscopic studies of the two resulting complexes reveal a strong correlation with their (mu-oxo)bis(mu-acetato)diiron(III) core structure.

Naturally‐occurring B12‐dependent enzymes catalyze various molecular transformations that are of particular interest from the viewpoint of biological chemistry as well as synthetic organic chemistry. Inspired by the unique property of the B12‐dependent enzymes, various catalytic reactions have been developed using its model complex. Among the B12 model complexes, heptamethyl cobyrinate, synthesized from natural vitamin B12, is highly soluble in various organic solvents and a redox active cobalt complex with an excellent catalysis in electroorganic synthesis. The electrochemical dechlorination of pollutant organic chlorides, such as DDT, was effectively catalyzed by the B12 complex. Modification of the electrode surface by the sol‐gel method to immobilize the B12 complex was also developed. The B12 modified electrodes were effective for the dehalogenation of organic halides with high turnover numbers based on the immobilized B12 complex. Electrolysis of an organic halide catalyzed by the B12 complex provided dechlorinated products under anaerobic conditions, while the electrolysis under aerobic conditions afforded oxygen incorporated products, such as an ester and amide along with dechlorination. Benzotrichloride was transformed into ethylbenzoate or N,N‐diethylbenzamide in the presence of ethanol or diethylamine, respectively. This amide formation was further expanded to a unique paired electrolysis. Electrochemical reductions of an alkene and alkyne were also catalyzed by the B12 complex. A cobalt‐hydrogen complex should be formed as a bioinspired intermediate. Using the B12 complex, light‐assisted electrosynthesis was also developed to save the applied energy. [ABSTRACT FROM AUTHOR]