Synthesis, structure, spectral characterization, electrochemistry and evaluation of antibacterial potentiality of a novel oxime-based palladium(II) compound

• Synthesis of oxime-based ligand and its Pd(II) complex.
• Spectroscopic aspects and X-ray single crystal structure of the complex.
• Quasi-reversible Pd(II)/Pd(I) reduction couple.
• This complex exhibits satisfactory bactericidal as well as bacteriostatic activity.
• The bioactivity was substantiated by SEM study.

The title monomeric Pd(II) compound, [Pd(L)(Cl)], was synthesized in moderate yield out of the reaction of equimolar proportion of Na2[PdCl4] and 3-[(5-bromo-2-hydroxy-benzylidene)-hydrazono]-butan-2-one oxime (LH) in tetrahydrofuran milieu. LH is a 1:1 Schiff-base condensate of 2,3-butanedionemonoxime monohydrazone and 5-bromosalicylaldehyde. [Pd(L)(Cl)] has been characterized by C, H and N microanalyses, 1H and 13C NMR, FAB-MS, FT-IR, Raman spectra, UV–Vis spectra and molar electrical conductivity measurements. [Pd(L)(Cl)] is diamagnetic. Structural elucidation reveals that the palladium center in [Pd(L)(Cl)] is nested in ‘N2OCl’ coordination environment. The geometry around Pd in [Pd(L)(Cl)] is distorted square-planar. The redox behavior of [Pd(L)(Cl)] in DMF shows a reduction couple, Pd(II)/Pd(I) at −0.836 V versus Ag/AgCl. The in vitro antimicrobial activity of [Pd(L)(Cl)] was screened against both Gram-positive and Gram-negative human pathogenic bacteria. This bioactivity was substantiated with SEM study. [Pd(L)(Cl)] exhibits satisfactory bactericidal as well as bacteriostatic activity.

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