On the mechanism of reduction of maleate by a Co(I) complex with a macrocylic ligand in aqueous solutions

Abstract

2010) On the mechanism of reduction of maleate by a Co(I) complex with a macrocylic ligand in aqueous solutionsRecently, it was shown that a Ni(I) complex with a tetraazamacrocyclic ligand (Ni I (1, 4, 8, 11-tetraazacyclotetradecane) þ , NiðIÞL þ 2 , cyclam), reduces maleate in aqueous solutions. It was decided to investigate whether this is a general reaction of low valent transition metal complexes. In this study, the reactions of Co I L þ (L ¼ 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) with maleate were investigated. The effect of the addition of maleate to aqueous solutions containing this low valent metal complex, prepared via the pulse radiolysis technique, was studied. The d ! * complexes formed between the monovalent cobalt complex and maleate were detected and characterized by UV-Vis spectroscopy. The nature of the final products formed was studied and detailed mechanisms of the reduction processes are proposed. The mechanism and kinetics of the reaction of Co(I)L þ with maleate was studied applying pulse-radiolysis and analysis of the final products.

Developing electrochemical hydrogenation towards industrial application

“…Similar reactivity under reductive conditions was also reported for other alkenes earlier always accompanied by dimerization. [287][288][289][290] In combination with molecular nickel phosphine hydrogenation catalysts, 4 mediates the hydrogenation of alkynes and enones. 291 The application of the simple complex Ni(bpy) 3 2+ 5 (bpy = 2,2 0 -bipyridine) enabled the semihydrogenation of alkynes via molecular electrosynthesis.…”

“…Similar reactivity under reductive conditions was also reported for other alkenes earlier always accompanied by dimerization. 287–290 In combination with molecular nickel phosphine hydrogenation catalysts, 4 mediates the hydrogenation of alkynes and enones. 291…”