Highly-efficient N-arylation of imidazole catalyzed by Cu(II) complexes with quaternary ammonium-functionalized 2-acetylpyridine acylhydrazone

The reaction of (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium-chloride (HLCl) with copper(II) perchlorate led to mononuclear [CuLCl]ClO 4 complex (1). The same reaction with excess of sodium azide gives dinuclear azido double end-on bridged Cu(II) complex [Cu 2 L 2 (μ- 1,1 -N 3 ) 2 ](ClO 4 ) 2 (2). In both complexes hydrazone ligand is NNO coordinated in monodeprotonated formally neutral zwitter-ionic form. Complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray crystallography. Variable‐temperature magnetic susceptibility measurements for dinuclear Cu(II) complex showed intra-dimer ferromagnetic coupling between Cu(II) ions (J = 7.4 cm −1 ). DFT-BS calculations provided explanation for magnetic properties of dinuclear Cu(II) complex. Both complexes were shown to highly efficiently catalyze the N-arylation of imidazole and benzimidazole with electron-poor or electron-rich aryl iodides, under user-friendly and sustainable conditions. This is the peer-reviewed version of the following article: Milenković, M. R.; Papastavrou, A. T.; Radanović, D.; Pevec, A.; Jagličić, Z.; Zlatar, M.; Gruden, M.; Vougioukalakis, G. C.; Turel, I.; Anđelković, K.; et al. Highly-Efficient N-Arylation of Imidazole Catalyzed by Cu(II) Complexes with Quaternary Ammonium-Functionalized 2-Acetylpyridine Acylhydrazone. Polyhedron 2019, 165, 22–30. [https://doi.org/10.1016/j.poly.2019.03.001] Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3006]