Introducing Weakly Ligated Tris(trifluoromethyl)copper(III)
Vladimir Motornov, Martin Procházka, Nora Alpuente, Pedro Salvador, Petr Slavı́ček, Blanka Klepetářová, Xavi Ribas, Petr Beier
Abstract
Abstract Tris(trifluoromethyl)copper(III), Cu(CF 3 ) 3 , was prepared for the first time and fully characterized in the form of weakly coordinated highly reactive solvent neutral adducts (DMF) 2 Cu(CF 3 ) 3 and (MeCN)Cu(CF 3 ) 3 . Free Cu(CF 3 ) 3 is an elusive molecule of distorted T‐shaped geometry with Lewis acid properties, which is stabilized by solvation. Substitution of solvent molecules with monoanionic ligands in mild conditions afforded the first Cu(III)(CF 3 ) 3 carboxylates [Cu(CF 3 ) 3 (OAc)] − and [Cu(CF 3 ) 3 (OBz)] − and Cu(III) nitrito complex [Cu(CF 3 ) 3 (ONO)] − . An improved synthesis of valuable Grushin's trifluoromethylation reagents via the intermediacy of (MeCN)Cu(CF 3 ) 3 was developed. (DMF) 2 Cu(CF 3 ) 3 demonstrated promising properties in photoinduced radical C‐H trifluoromethylation. Oxidation state theoretical studies showed the Cu(CF 3 ) 3 compounds to be borderline between classical Cu(III) and inverted ligand field Cu(I) assignment.