Synthesis, crystal structure and investigation of the catalytic and spectroscopic properties of a Zn(II) complex with coumarin-hydrazone ligand

A Zn(II) complex with coumarin-hydrazone ligand, [ZnCl(HL)(CH3OH)(0.76)(H2O)(0.24)]center dot 0.24(CH3OH) (1), was synthesized from the reaction of equimolar amount of ZnCl2 center dot 4H(2)O and (E)-2-hydroxy-N'-(1-(2-oxo-2H-chromen-3-yl)ethylidene)benzohydrazide (H2L) in methanol solvent. The complex was characterized by elemental analysis, spectroscopic methods and single crystal X-ray diffraction studies. Single crystal X-ray analysis indicated that the Zn(II) ion in complex 1 has a distorted square pyramidal environment and the coumarin-hydrazone ligand is coordinated as a mononegative tridentate ONO-donor ligand, (HL)(-). The photoluminescent studies indicated that complex 1 has emission at about 470 nm. The catalytic potential of complex I was investigated for preparing tetrazole based compounds from the azide-nitrile cycloaddition reactions. The catalytic reactions were carried out in water as a green solvent. The results indicated that complex 1 is an active catalyst for preparing tetrazole compounds. The effects of temperature and electronic properties of the substituent connected to the nitrile group on the activity of this catalytic system were also considered. (C) 2018 Elsevier Ltd. All rights reserved.