[Copper(phenanthroline)(bisisonitrile)]⁺‑Complexes for the Visible-Light-Mediated Atom Transfer Radical Addition and Allylation Reactions

A series of heteroleptic [Cu­(phenantroline)­(bisisonitrile)]+-complexes was synthesized, and their structural, spectroscopic, and electrochemical properties were investigated. The new copper­(I) complexes were employed as photoredox-catalysts in the visible-light-mediated atom transfer radical addition (ATRA). Especially, [Cu­(dpp)­(binc)]­BF4 (6a-BF4)­(dpp = 2,9-diphenyl-1,10-phenanthroline; binc = bis­(2-isocyanophenyl) phenylphosphonate) proved to be highly active owing to an enhanced excited-state lifetime compared to the commonly employed [Cu­(dap)2]Cl (1-Cl)­(dap = 2,9-di­(p-anisyl)-1,10-phenanthroline). Furthermore, the catalyst could be applied to allylation reactions with trimethylallylsilane under mild visible-light photoredox conditions.