Hydrophobic vitamin B12. Part 19:For Part 18 see ref. 22. Electroorganic reaction of DDT mediated by hydrophobic vitamin B12

Abstract

The controlled-potential electrolysis of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) was carried out at -1.4 V vs. Ag-AgCl in the presence of a hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate. DDT was dechlorinated to form 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD), 1,1-bis(4-chlorophenyl)-2,2-dichloroethylene (DDE), 1-chloro-2,2-bis(4-chlorophenyl)ethylene (DDMU) and 1,1,4,4-tetrakis(4-chlorophenyl)-2,3-dichloro-2-butene (TTDB)(E/Z), and quantitative recovery of the catalyst after the electrolysis was confirmed by electronic spectroscopy. A photo-sensitive intermediate having a cobalt-carbon bond formed during the electrolysis was characterized by electronic spectroscopy. A mechanism for the formation of various dechlorinated products was investigated by using deuterium solvents and various spectroscopic measurements such as UV-VIS and the EPR spin-trapping technique.

Enhanced reductive dechlorination of tetrachloroethene during reduction of cobalamin (III) by nano-mackinawite

“…Literatures show that active transition metal coenzymes such as cobalamin(III) (Co(III)), hematin, and cofactor F 430 can play an important role as electron transfer mediator (ETM) in reductive dechlorination of chlorinated organics [11,[14][15][16][17][18]. Among the coenzymes, Co(III) shows the fastest dechlorination kinetics of PCE and TCE with titanium(III) citrate [19].…”

Vitamin B12 Enables Consecutive Generation of Acyl and Alkyl Radicals from One Reagent

“…Dechlorination is one of the biomimetic reactions catalysed by vitamin B 12 thus utilizing halogenated derivatives in B 12 -catalyzed reactions is often plagued by the formation of a significant amount of dehalogenated products. [34][35][36][37][38][39][40][41]50] In accordance, the reaction with thioester 8 possessing the chlorine substituent afforded desired product 14 in only 23 % yield in contrast to 64 % for the respective bromide. For substrates with more reactive benzyl substituents the competing dehalogenation predominated under optimized conditions, for thioester S-pyridin- 2-yl-3-(chloromethyl)benzothioate (11) product 22 formed in only 29 % yield, while substrate (10) with benzyl bromide moiety was entirely dehalogenated affording product 23.…”

Catalytic reduction of 4,4′-(2,2,2-trichloroethane-1,1-diyl)bis(methoxybenzene) (methoxychlor) with nickel(I) salen electrogenerated at reticulated vitreous carbon cathodes

“…Although electrocatalytic reduction of methoxychlor has not previously been explored, it is useful to note several earlier publications pertaining to catalytic reduction of a close analogue, 4,4ʹ-(2,2,2-trichloroethane-1,1-diyl)bis(chlorobenzene) (DDT), by means of electrogenerated cobalt(I) species [17][18][19][20][21]. However, when one considers the catalytic reduction of methoxychlor, there is a distinct advantage to the use of electrogenerated nickel(I) salen [22]; the latter is not air-sensitive, which makes it more stable and easier to use than cobalt (I) salen.…”