Supramolecular system composed of B12 model complex and organic photosensitizer: impact of the corrin framework of B12 on the visible-light-driven dechlorination without the use of noble metals
摘要:
The visible-light-driven dechlorination system without the use of a noble metal has been developed. We screened the combination of cobalt catalysts having square-planar monoanionic ligands (hydrophobic B-12 model complex 1/imine-oxime type complex 2) and typical red dyes (Rose Bengal 3/Rhodamine B 4/Nile Red 5) for the construction of a dehalogenation system via a noble-metal-free and visible-light-driven process. The combination of the hydrophobic B-12 model complex 1 and Rose Bengal 3 exhibited the highest catalytic activity to 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) to form the monodechlorinated compound, 1,1-bis(4-chlorophenyl)-2,2-dichloroethane, as the major product. The prolonged photocatalysis of DDT by the B-12-Rose Bengal system afforded the tri-dechlorinated compound, trans-4,4-dichlorostilbene, as the major product. Furthermore, we investigated the mechanism of the dehalogenation cycle using various methods such as UV-vis spectroscopy and laser flash photolysis. Finally, we clarified the advantage of using the hydrophobic B-12 model complex 1 as an electron acceptor as well as a cobalt catalyst in the organic dye-involved photocatalysis.
acid, was effectively immobilized on TiO 2 , and the hybrid Ti0 2 was characterized by UV―vis, XPS, MALDI-TOFMS as well as TEM analysis. The hybrid Ti0 2 exhibits high reactivity for dehalogenation of various organichalides such as phenethyl bromide, benzyl bromide, and 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) under irradiation with UV light at room temperature.
Dechlorination of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) was catalyzed by a hydrophobic vitamin B(12), heptamethyl cobyrinate perchlorate, with a visible light irradiation system containing a [Ru(ii)(bpy)(3)]Cl(2) photosensitizer, and the hydrophobic vitamin B(12) showed high catalytic efficiency and stability during the reaction.
作者:Larry L. Miller、Raginder S. Narang、Gerald D. Nordblom
DOI:10.1021/jo00942a030
日期:1973.1
Supramolecular system composed of B<sub>12</sub> model complex and organic photosensitizer: impact of the corrin framework of B<sub>12</sub> on the visible-light-driven dechlorination without the use of noble metals
The visible-light-driven dechlorination system without the use of a noble metal has been developed. We screened the combination of cobalt catalysts having square-planar monoanionic ligands (hydrophobic B-12 model complex 1/imine-oxime type complex 2) and typical red dyes (Rose Bengal 3/Rhodamine B 4/Nile Red 5) for the construction of a dehalogenation system via a noble-metal-free and visible-light-driven process. The combination of the hydrophobic B-12 model complex 1 and Rose Bengal 3 exhibited the highest catalytic activity to 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) to form the monodechlorinated compound, 1,1-bis(4-chlorophenyl)-2,2-dichloroethane, as the major product. The prolonged photocatalysis of DDT by the B-12-Rose Bengal system afforded the tri-dechlorinated compound, trans-4,4-dichlorostilbene, as the major product. Furthermore, we investigated the mechanism of the dehalogenation cycle using various methods such as UV-vis spectroscopy and laser flash photolysis. Finally, we clarified the advantage of using the hydrophobic B-12 model complex 1 as an electron acceptor as well as a cobalt catalyst in the organic dye-involved photocatalysis.