Synthesis, characterization, antimicrobial and anti-biofilm studies of Ni(II) complex with Schiff base derived from 2-thiophene carboxaldehyde and phenyl acetic hydrazide

Abstract

Schiff base titled (Z)-2-phenyl-N'-(thiophen-2-ylmethylene)acetohydrazide (HL) and its Ni (II) complex were obtained by the condensation of 2-thiophene carboxaldehyde and phenyl acetic hydrazide. The ligand (HL) was characterized using elemental analysis, Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1HNMR ), Ultraviolet–visible (UV–Vis.) spectroscopy, and Liquid chromatography–mass spectrometry (LC/MS) methods. Elemental analysis, FTIR, UV–Vis, and X-ray single crystal studies were used to elucidate the structure of the [NiL2] complex. The brown single crystal structure of the Ni(II) complex was elucidated by X-ray diffraction technique, and the complex structure was found to crystallize in a triclinic crystal system with P1¯ space group. With symmetries of 1-x, 1-y, and -z and -x, 1-y, and 1-z, the nickel atoms in the asymmetric unit are positioned on an inversion centre. It was determined that the antimicrobial activity of the newly synthesized HL and [NiL2] compounds was high on clinically important strains and had low minimal inhibitory concentration (MIC) values. In addition, the anti-biofilm activity of the compounds showed 45.14 % and 42.28 % biofilm inhibition, respectively, on the E. coli ATCC 25,922 strain at a concentration of 100 µg/ml, whereas it showed 56.36 % and 42.28 % inhibition, respectively, on the P. aeruginosa ATCC 278533 strain showed an inhibitory effect.