Mixed ligand transition metal(II) complexes of Knoevenagel condensate-β-ketoesters with 1,2-diaminobenzene: Synthesis, structural characterization, electrochemical behaviour and antimicrobial study

Abstract

693-699New Schiff base mixed ligand transition metal complexes of the composition, [ML(DB)2]Cl2, where M=Cu(II ), Ni(II), Co(ll) and Zn(II); L=Knoevenagel <span style="font-size:13.5pt;mso-bidi-font-size: 6.5pt;font-family:HiddenHorzOCR;mso-hansi-font-family:Arial;mso-bidi-font-family: HiddenHorzOCR;color:black">condensate- <span style="font-size:19.0pt; mso-bidi-font-size:12.0pt;font-family:Arial;mso-fareast-font-family:HiddenHorzOCR; color:black">β<span style="font-size:19.0pt;mso-bidi-font-size:12.0pt; font-family:HiddenHorzOCR;mso-hansi-font-family:Arial;mso-bidi-font-family: HiddenHorzOCR;color:black">-<span style="font-size:20.5pt;mso-bidi-font-size: 13.5pt;color:black">ketoesters <span style="font-size:15.0pt;mso-bidi-font-size: 8.0pt;font-family:Arial;color:black">derived from 1-hydroxybenzaldehyde and methyl ester of 3- oxobutanoic acid (HMOA)/ethyl ester of 3-oxobutanoic acid (HEOA)/N-phenyl-2-oxobutanamide (HPOB) and 1,2- diaminobenzene(DB), were synthesized. They were characterized on the basis of elemental analyses, magnetic susceptibility, FAB-mass, electronic absorption spectra, IR, 1H NMR, 13C NMR and ESR data. All the complexes exhibit octahedral geometry. Their magnetic susceptibility measurements and conductance data provide evidence for the monomeric and 1:2 electrolytic natures or the complexes. respectively. The electrochemical behaviour, the anodic and cathodic potential and the number of electron transfer were calculated using cyclic voltammogram. The antimicrobial activities of the ligand and its complexes have been studied by screening the compounds against various microorganisms (both Gram-positive and Gram-negative bacteria) and the results have been compared with the standard drug, ampicillin. The data showed that the complexes were highly active than that of the free ligand and the standard. </span