Complexes of Cu(II) and Ni(II) with Bis(Phenylthiosemicarbazone): Synthesis, Spectral, EPR and in Vitro ‐ Antibacterial and Antioxidant Activity

Abstract

The synthesis of Cu(II) and Ni(II) complexes with 2,6‐diacetylpyridine bis(4‐phenyl‐3‐thiosemicarbazone) (L) ligand have been reported. The ligand was characterized by elemental analysis and spectral (IR and 1H NMR) studies and its complexes were characterized by electronic, UV/VIS, EPR and IR studies. The room‐temperature EPR spectrum of Cu(II) complex was recorded and the analysis of its spectrum gave {g} tensor with g1 = 2.25, g2 = 2.15, and g3 = 2.07 which were of distorted octahedral structure. The electronic spectrum of Ni(II) complex indicated the octahedral geometry around the Ni(II) ion. Their antibacterial activities were evaluated by the diameter of zone of inhibition (mm) against four bacteria such as B. subtilis, S. aureus, E. coli and K. pneumonia. The ligand and the 6‐coordinate Ni(II) complex did not inhibit the growth of the test organisms, while the Cu(II) complex showed good antibacterial activity than parent ligand against the same bacteria. The free ligand and its metal complexes have been tested for in vitro ‐ antioxidant activity by reduction of 1,1‐diphenyl‐2‐picryl hydrazyl (DPPH) and iron induced lipid peroxidation using rat brain homogenate. The ligand exhibited potent in vitro ‐ antioxidant activity than its Ni(II) and Cu(II)complexes.

Spectral, NLO, Fluorescence, and Biological Activity of Knoevenagel Condensate of β-Diketone Ligands and Their Metal(II) Complexes

“…Co(II) complex (L1b) exhibits three d-d bands at 9541 cm −1 , 16420 cm −1 , and 19047 cm −1 assigned to 4 T 1g (F) → 4 T 2g (F), 4 T 1g → 4 A 2g , and 4 T 1g (F) → 4 T 1g (P) transitions [27], respectively, and the magnetic moments for the cobalt(II) complexes in the 4.71 BM range are supportive of octahedral geometry [28]. Similarly, Ni(II) complex (L1c) shows bands at 10582 cm −1 , 14471 cm −1 , and 25038 cm −1 due to 3 A 2g → 3 T 2g , 3 A 2g → 3 T 1g (F), and 3 A 2g → 3 T 1g (P) transitions [29], respectively. The magnetic moment values of the above Ni(II) complexes fall in the range of 3.21 BM, which is in the normal range observed for octahedral Ni(II) complexes (μ eff = 2.9-3.3 BM) [26,30].…”

Facile Heterocyclic Synthesis and Antibacterial Activity of Substituted Isoxazol‐5(4H)‐ones

“…The in vitro antibacterial activity evaluation of our compounds was carried out by the cup‐plate agar diffusion method, based on the recommendations of the National Clinical Committee Laboratory Standards (NCCLS). The strains of pathogenic bacteria used are responsible for foodborne illness (G+ Clostridium perfringens [CECT 486]/G−: Escherichia coli [CECT 515], Enterococcus faecium [DSM 20477]) and are classified according to the inhibitory diameter.…”

Synthesis and spectral studies on metal complexes of s-triazine based ligand and non linear optical properties

“…3 T 1g (P)) transitions which strongly favors an octahedral geometry around metal ion and the magnetic moment value 2.94 B.M. obtained is the normal range of octahedral symmetry [36]. The electronic absorption spectrum of cobalt(II) complex (6) gives absorption bands at 9569, 16,260, 21,413 cm À1 due to ( 4 T 1g (F) ?…”