1. Macrocyclic Copper(II) Complexes as Catalysts for Electrochemically Mediated Atom Transfer.
- Author
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Naher M, Su C, Harmer JR, Williams CM, and Bernhardt PV
- Abstract
Copper-catalyzed electrochemical atom transfer radical addition ( e ATRA) is a new method for the creation of new C-C bonds under mild conditions. In this work, we have explored the reactivity of an analogous series of N
4 macrocyclic CuII complexes as e ATRA precatalysts, which are primed by reduction to their monovalent oxidation state. These complexes were fully characterized structurally, spectroscopically, and electrochemically. A spectrum of radical activation reactivity was found across the series [CuI (Me4 cyclen)(NCMe)]+ (Me4 cyclen = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane), [CuI (Me4 cyclam)(NCMe)]+ (Me4 cyclam = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), and [CuI (Me2 py2 clen)(NCMe)]+ (Me2 py2 clen = 3,7-dimethyl-3,7-diaza-1,5(2,6)-dipyridinacyclo-octaphane). The rate of radical production by [Cu(Me2 py2 clen)(NCMe)]+ was modest, but rapid radical capture to form the organocopper complex [CuI (Me2 py2 clen)(CH2 CN)] led to a dramatic acceleration in catalysis, greater than seen in any comparable Cu complex, but this led to rapid radical self-termination instead of radical addition.- Published
- 2024
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