title: Electrochemistry and catalytic properties of amphiphilic vitamin B12 derivatives in nonaqueous media.
abstract: The reduction pathway of cobalester (CN)Cble, an amphiphilic vitamin B12 derivative, was investigated in organic solvents under electrochemical conditions and compared with mono- and dicyanocobyrinates. The redox characteristics were determined using cyclic voltammetry and spectroelectrochemical methods. The presence of a nucleotide moiety in B12-derivative impedes the in situ formation of dicyano-species thus facilitating the (CN)Co(iii) to Co(i) reduction. The (CN)Cble shows stepwise reduction to Co(i) via (CN)Co(ii). The reduction of (CN)Co(ii)/Co(i) was found to depend on cyanide-solvent exchange equilibrium with weakly coordinating solvents and bulky peripheral chains promoting intact (CN)Co(ii) species existence. The studied complexes were also utilized as catalysts in bulk electrolysis of benzyl bromide affording bibenzyl in very good yield.
authors.affiliation: Institute of Organic Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. dorota.gryko@icho.edu.pl.
authors.forename: M
authors.initials: M
authors.lastname: Giedyk
authors.affiliation: Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka, 819-0395, Japan. shimakoshi@mail.cstm.kyushu-u.ac.jp yhisatcm@mail.cstm.kyushu-u.ac.jp.
authors.forename: H
authors.initials: H
authors.lastname: Shimakoshi
authors.affiliation: Institute of Organic Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. dorota.gryko@icho.edu.pl.
authors.forename: K
authors.initials: K
authors.lastname: Goliszewska
authors.affiliation: Institute of Organic Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. dorota.gryko@icho.edu.pl.
authors.forename: D
authors.initials: D
authors.lastname: Gryko
authors.affiliation: Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka, 819-0395, Japan. shimakoshi@mail.cstm.kyushu-u.ac.jp yhisatcm@mail.cstm.kyushu-u.ac.jp.
authors.forename: Y
authors.initials: Y
authors.lastname: Hisaeda
mesh_terms: D001593:Benzyl Compounds / Q000737:chemistry; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry; D003486:Cyanides / Q000737:chemistry; D055664:Electrochemical Techniques; D004572:Electrolysis; D010084:Oxidation-Reduction; D012997:Solvents / Q000737:chemistry*; D013053:Spectrophotometry; D014805:Vitamin B 12 / Q000031:analogs & derivatives*
chemical_list: D001593:Benzyl Compounds; D003486:Cyanides; D012997:Solvents; D003035:Cobalt; D014805:Vitamin B 12; C038682:benzyl bromide