Anion modulated structural variations in copper(II) complexes with a flexidentate ligand derived from 2-((2-aminoethyl)amino)ethan-1-ol: Synthesis and spectroscopic and X-ray structural characterization

Flexidentate ligand, HL has been prepared by the condensation of aminoethylethanolamine (AEEA) with benzoylacetone (bezac). On reaction with copper(II) salts it gives complexes CuLClO₄.H₂O (1), CuLN₃ (2) and [Cu₃L₃Br]Br₂ . H₂O (3). All complexes have been characterized by X-ray crystallography. The results show that the hydroxyl group of the flexidentate ligand can coordinate to the Cu(II) center or remain as an uncoordinated group. In (1), the coordination number around the copper(II) ion is five coordinated and the ligand is tetradentate with the OH group coordinated to the copper(II) ion. Complex (2) has a square planar geometry and the L⁻ ligand is tridentate with the hydroxyl group left uncoordinated. The X-ray diffraction analysis of the trinuclear complex (3) shows that the copper(II) centers are five-coordinate and L− is a tetradentate ligand with the hydroxyl group being both terminal and bridging. The Hirshfeld surface analysis and the 2D fingerprint plot were used to analyze all of the intermolecular contacts in the crystal structures.