Synthesis, characterization and crystal structures of copper(II) complexes containing multidentate polypyridine ligands†

Abstract

Three mononuclear copper(II) complexes of the tetrapyridyl ligand bis[di(2-pyridyl)methyl]amine have been synthesised and crystallized. The corresponding X-ray crystal structures displayed different geometries around the metal ion, which are mainly induced by the nature of the anionic ligands of the copper(II) salt. Cu(BDPMA)Cl₂ 1, Cu(BDPMA)(SO₄)MeOH 2 and [Cu(BDPMA)(BF₄)CH₃CN]BF₄ 3 exhibited distorted trigonal bipyramidal, square pyramidal and octahedral geometries, respectively. FAB mass spectra and ESR spectra of crystalline samples and frozen solutions suggested that the overall structures are not modified for complexes 1–3 on going from the solid to the solution states.