Synthesis, structural and magnetic characterization of a copper(II) complex of 2,6-di(1H-imidazol-2-yl)pyridine and its application in copper-mediated polymerization catalysis

Abstract

The 2,6-di(1H-imidazol-2-yl)pyridine (H2dimpy) ligand is synthesized and suggested as an alternative ligand for copper mediated catalysis. A Cu(II) complex was obtained with this ligand and characterized via ESI-MS, FT-IR, UV–vis and the structure was confirmed by single crystal XRD. The crystal showed the [Cu2(H2dimpy)2(μ-Cl)2](PF6)2·2H2O dimeric complex, in which Cu(II) is in a distorted square-pyramidal geometry (τ=0.301). Ferromagnetic coupling with J=-11.1 cm−1 was confirmed by experiment and corroborated by density functional calculations. In order to evaluate the applicability of H2dimpy in atom transfer radical polymerization (ATRP), polystyrene was produced in DMF solution at low polydispersity (1.3) while maintaining the livingness of the polymer chain. The good performance of the H2dimpy compared to a standard ligand for ATRP (5,5′-dimethyl-2,2′-dipyridyl) indicates that it is suitable for this reaction.