Novel Cu(II) Complexes of 3,5-Di-tert-butyl-2-hydroxy benzylidene-2-aminobenzhydrazide: Synthesis, Spectral Characterization, Antimicrobial and Antioxidant Properties

The present study reports the synthesis and characterization of three copper(II) complexes of novel hydrazone ligand 3,5-di-tert-butyl 2-hydroxy benzylidene 2-aminobenzhydrazide [H2L]. The complexes viz. [Cu(HL)(Cl2)H2O] (1a), [Cu(HL)(NO3)]·2/3H2O (2a), [{Cu(HL)}2(µ-SO4)]·11/3H2O (3a) and ligand (H2L) were characterized by elemental analysis, spectroscopic techniques (FT-IR, 1H NMR, 13C NMR, UV-visible, LC-MS and PXRD), molar conductance, magnetic susceptibility measurement and thermal analysis. Thermal data of complexes at different temperatures provides the valuable information about different fragments of structure, their molecular weights, thermal stability, coordinated and fractional number of lattice water molecules in the synthesized metal complexes. Complex 1a exhibit distorted octahedral geometry, whereas complexes 2a and 3a exhibit square planer to square pyramidal geometry inferred from magnetic, electronic and spectroscopic data. In all the complexes, the ligand coordinate to metal in tridentate mode through the ONO [OKetonic, Nazomethine and Ophenolic] chelating system. The antibacterial potential of synthesized molecules have been determined against Gram+ve and Gram-ve bacteria Bacillus subtilis, Bacillus cereus, Escherichia coli, Pseudomonas vulgaris, Staphylococcus aureus, etc. The antioxidant activity was also determined using DPPH radical scavenging assay. It is clear that the new complexes are good active compounds for use in a variety of applications.