Synthesis and Aerobic Oxidation of Perfluoroalkyl d10 Metal Complexes Supported by 2,7-Dimethyl-1,8-Naphthyridine

Abstract

The coordination chemistry of 2,7-dimethyl-1,8-naphthyridine has been explored with perfluoroalkyl d¹⁰ metals, Cu^I, Zn^II, and Ag^I. This ligand was shown to form dicoordinate Cu^I and Ag^I mono-perfluoroalkyl complexes where naphthyridine coordinates with only one N-donor, while bidentate coordination with both N-atoms was observed in Zn bis(perfluoroalkyl) complexes forming a strained four-membered chelate ring. Copper complexes undergo facile oxidation in the presence of air or excess O₂ to give tetracoordinate Cu^II complexes coordinated to perfluorocarboxylates formed by oxygenation of the metal-adjacent α-CF₂ position of the corresponding perfluoroalkyl ligands. Another type of product formed by the oxidation of perfluoroethylcopper(I) complexes in the presence of substoichiometric O₂ are binuclear Cu^I⋅⋅⋅Cu^I complexes with two perfluorocarboxylate ligands. In the presence of an external substrate, alkene, O-atom transfer was observed to give oxygenated products, resembling the recently reported O-transfer reactivity of naphthyridine-supported Ni long-chain perfluoroalkyl complexes.