A new dinuclear copper(II) complex of unexpected formation with the 1-[2-(ethylamino)methyl]pyrazole ligand presents a curious Ferris wheel-like shape at supramolecular self-assembly

The crystallization of [CuCl2(L1)] (L1 = bis-[(1-pyrazolyl)methyl]ethylamine) by ethanol/hexane solvent diffusion afforded the compound [CuCl2(L2)]2 (L2 = 1-[2-(ethylamino)methyl]pyrazole), which has been characterized by single-crystal X-ray diffraction, elemental analysis, conductivity measurements, infrared and UV–vis spectroscopies. There are very few polynuclear complexes with N-alkylaminopyrazole ligands reported so far. Especially L2 ligand, which is forming the binuclear copper(II) complex has been obtained for the first time here. The crystal structure consists of a dimeric unit in which the copper(II) atoms are five-coordinated in a distorted square pyramidal geometry with two nitrogen and two chlorine atoms in the base and one chlorine in the apical vertex. At the supramolecular level attractive structural designs are obtained, particularly, a peculiar Ferris wheel-like shape along the (110) direction. Hydrogen bonds constitute the main pillars of the supramolecular self-assembly observed.