Synthesis, structure, magnetic properties and DFT calculations of novel bis-(5-tetrazolyl)amine copper(II) complexes

Four new multidimensional copper(II) complexes [Cu(BTA)(2,2′-bipy)H2O] (1), [Cu(BTA)(1,10′-phen)] (2), [Cu2(BTA)2(H2O)4] (3) and [Cu(BTA)(en)]n (4) have been synthesized by conventional and hydrothermal reactions of the bis(5-tetrazolyl)amine (H2BTA) with copper(II) salts in the presence of different ancillary ligands. X-ray diffraction studies on these compounds show 1 and 2 are mononuclear entities, in which the BTA ligand acts in a chelate coordination mode and the copper atoms exhibit a coordination environment intermediate between trigonal-bipyramidal and square-pyramidal for 1 and between square-planar and tetrahedral for 2. Complex 3 consists of centrosymmetric dinuclear molecules with the ligand acting in a μ2-1,1′:2 chelate/bridging tridentate coordination mode and 4 is a linear zigzag neutral chain bearing a BTA bridging ligand in a μ2-1,1′:3 chelate/bridging tridentate coordination mode. Complexes 3 and 4 exhibit antiferromagnetic and very weak ferromagnetic interactions, respectively. DFT calculations have been performed in order to explain their respective magnetic behaviors.

Four new multidimensional copper(II) complexes have been synthesized by conventional and hydrothermal reactions of the bis(5-tetrazolyl)amine (H2BTA) with copper(II) salts in the presence of different ancillary ligands. X-ray diffraction studies on these compounds show a great structural diversity highlighting a centrosymmetric dinuclear molecule and a linear zigzag neutral chain. These complexes exhibit antiferromagnetic and very weak ferromagnetic interactions, respectively. DFT calculations have been performed in order to explain their respective magnetic behaviors.Figure optionsDownload as PowerPoint slideHighlights
► Four novel copper complexes with bis(5-tetrazolyl)amine (H2BTA).
► Few copper(II) complexes bearing this ligand have been reported so far.
► Antiferromagnetic and ferromagnetic interactions are studied.
► The sign and value of magnetic couplings are analyzed by DFT calculations.