Synthesis, characterization and crystal structure of [Cu2(LH)2]•(ClO4)2. Influence of the weak Cu•••O(perchlorate) interaction on the structure of Cu2N2O2 metallocycle

Abstract

The diimine-dioxime ligand, 4,9-diaza-3,10-diethyl-3,9-dodecadiene-2,11-dione bisoxime (LH2), containing a N4 donor set was prepared by Schiff base condensation of 2-hydroxyimino-3-pentanone and 1,4-diaminobutane in two ways: in protic and in aprotic solvent. Higher yield of (LH2) imine was obtained when the synthesis was carried out using protic solvent (C2H5OH) instead of aprotic benzene (78% and 30%, respectively). Cu(II) metal complex of diimine-dioxime was synthesized in CH3OH from metal salt and LH2 in mole ratio 1:1. The isolated complex was characterized by the elemental analysis, IR spectroscopy and cyclic voltammetry. The structure of [Cu2(LH)2]•(ClO4)2 was determined by the single-crystal X-ray diffraction analysis. Comparison with the structurally related diimine-dioxime Cu(II) complexes revealed the influence of the weak Cu•••O(perchlorate) interaction on the geometry of the metallocycle. [Projekat Ministarstva nauke Republike Srbije, br. 45015, br. 172013, br. 172065 i br. 172014]

Keywords

• Cu(II) complex
• weak interactions
• supramolecular aggregates
• diimine-dioxime ligand