1 Synthesis , X - ray Crystal Structures , Computational 2 Studies and Catechol Oxidase Activity of New 3 Acylhydrazone Derivatives 4

To make low-cost catalytic materials that mimic the activity of tyrosinase enzymes 29 (Catechol oxidase) is an exciting challenge of biochemical technology. Herein, we report the 30 synthesis of a series of acylhydrazone-pyrazoles based biomolecule materials (L1-L7) with superior 31 catecholase activity. These biomolecules were synthesized by a one pot chemical condensation 32 between 5-methyl-1H-pyrazole-3-carbohydrazide and benzaldehyde derivatives. The X-ray single 33 crystal diffraction (XRD) for two ligands L1 and L2 have been studied and the molecular structures 34 were optimized and confirmed using the density functional theory (DFT/B3LYP) method. Copper 35 (II) complexes of the biomolecules (L1-L7), generated in-situ, and were studied for their catalytic 36 activities towards the oxidation reaction of catechol to ortho-quinone according to two parameters: 37 the nature of the ligand and the nature of counter anion. The L7-CuSO4 was found to have an 38 excellent catalytic activity (105.42 μmol·L−1·min−1) among the catalysts recently reported in the 39 existing literature. 40