Synthesis, crystal structure, and spectroscopy of (azido-N1)bis(2,2′-bi-imidazoline)copper(II) perchlorate

The compound [Cu(biz)2(N3)](ClO4) (biz = 2,2′-bi-imidazoline) has been synthesized and characterized by X-ray crystallography and infrared spectroscopy. In addition, EPR and magnetic measurements have been performed. The compound crystallizes in the monoclinic space group P21/c, with a = 9.2716(2), b = 27.6454(4), c = 7.4285(1) Å, β = 102.1417(6)°, V = 1861.46(5) Å3, and Z = 4. The coordination geometry around the Cu(II) ion is distorted square pyrimidal, with 4 nitrogen atoms of 2 bis-chelating ligand molecules in the basal plane and one nitrogen of the azide molecule in the apical position. The perchlorate ion is noncoordinating. In the infrared the vibrations of the coordinated azide anion are observed at 2050, 1286, and 620 cm−1, while the vibrations of the free perchlorate anion are observed at 1071, 1035, and 919 cm−1; Cu—N vibrations are observed at 418 and 336 cm−1. The molecules are connected in the lattice via relatively strong hydrogen bonding between the N—H groups at the back of the biz ligand and the N1 and N3 atoms of the azide ligand forming layers. No intermolecular magnetic interaction was observed for this compound.