Structure and EPR investigation of Cu(II) bifluoride complexes with zwitterionic N-hydroxyimidazole ligands

Abstract Copper(II) bifluoride complexes with zwitterionic N-hydroxyimidazole ligands 1-hydroxy-4methyl-2-(pyridin-2-yl)-5-phenylimidazole (HL1) and 1-hydroxy-2-(pyridin-2-yl)-4,5,6,7-tetrahydrobenzimidazole (HL2) were synthesized as a result of reaction of copper(II) fluoride dihydrate with corresponding ligand (metal-to-ligand ratio equal to 1:2) in hydrofluoric acid. The X-ray crystal structures of two compounds CuL12(HF2)2 and [CuL22(HF2)]2·(H2F3)·(H1.4F2.4) were solved. Solvent molecules enter the crystal structures stabilizing them due to the formation of hydrogen bonds. Both of the complexes were investigated with the EPR technique giving the spectra with S=1/2, gxx=2.06(1), gyy=2.11(1), gzz=2.21(1) and S=1, gxx=2.07(1), gyy=2.07(1), gzz=2.24(1), |D|=61.6(5) mT, |E|=0 (5) mT, respectively. The magnetic susceptibility measurements results correlate with EPR data. The calculations were performed in the framework of DFT theory; the g-tensors calculated are in good agreement with experimentally obtained.