Synthesis, spectroscopic and crystallographic studies on two copper(II) benzimidazole complexes: Supramolecular frameworks built from N-H ... O, N-H ... Cl and O-H ... Cl hydrogen bonds

Abstract

The tridentate ligands 2,6-bis(benzimidazole-2'-yl)pyridine (L¹) and N,N-bis(benzimidazole-2'-yl-methyl )amine (L²) with N₃ donor set form the corresponding mononuclear [Cu (L¹)(ClO₄)(Cl)].H₂O (<b>1</b>) and [Cu (L²)(ClO₄)(Cl)].H₂O (<b>2</b>) complexes, which have been characterized by elemental analysis. UV-Vis spectra, IR , EPR and magnetic moment studies. Single crystal X-ray structure studies for both the complexes show that coordination geometrics around the copper centre are best described as distorted square pyramidal with three nitrogen atoms of tridentatc ligand and a chloride ion defining the equatoriial planes. The apical positions in the complexes are occupied by a perchlorate O atom in <b>1</b> and a chloride ion in <b>2</b>. Metal directed assembly of infinite two-dimensional supramolecular network stabilizes the crystal structures of both complexes in the solid state. The global magnetic interactions in complexes <b>1</b> and <b>2</b> are found to be paramagnetic with μ_eff values of 1.65 BM and 1.63BM, respectively, which are typical for a Cu(II) <i>d</i>⁹ system.