Designing, Synthesis, Spectral Characterization of Antimicrobial and Dna Active Tridentate Schiff Base Ligands and Their Complexes

Abstract

New neutral Schiff base tridentate ligand transition metal complexes of the composition, ML 2, where M= Cu(II), Ni(II), Co(II) and Zn(II); L= ligands derived from semicarbazide hydrochloride and 2,4pentanedione/methyl acetoacetate/acetoacetanilide, were synthesized and characterized by elemental analyses, magnetic susceptibility, IR, UV-Vis., 1 H-NMR, 13 C-NMR, CV, ESR, and FAB-mass spectral techniques. Electronic absorption spectra of the complexes indicate an octahedral geometry around the metal ion. The magnetic susceptibility measurements and low conductance data provide evidence for the monomeric and neutral natures of the complexes respectively. The electrochemical behaviour, the anodic and cathodic potential and the number of electron transfer were calculated using cyclic voltammogram. The X-band ESR spectrum of copper complex in DMSO at 300 K and 77 K was recorded and its salient features are reported. The antimicrobial activities of the ligands and their complexes have been studied by screening the compounds against the bacteria E. coli, P.aeruginosa, P.mirabilis, S. typhi, and B.subtilis and also the fungi C.albicans and R. stolonifer and results have been compared with the standard drug, amphicillin. The data indicate that most of the metal complexes have higher antimicrobial activity than the free ligands and the standard. The DNA cleavage experiments, performed using gel electrophoresis with the corresponding metal complexes in the presence of H 2 O 2 showed all the complexes afford a pronounced discernible DNA cleavage evidenced by the disappearance of Form I (supercoiled) of plasmid and the production of Form III (linear).

Interaction of E. coli DNA with diazine-bridged late first row transition metal complexes derived from hexadentate compartmental ligands: an approach to DNA cleavage/binding studies

“…A band at *750 cm -1 is assigned to the 4 T 1g ? 4 A 2g transition, well within the range for octahedral Co II complexes [22,23]. In [Ni 2 L 2 (l-Cl)Cl 2 (H 2 O) 2 ], the bands around 680, 530 and 495 nm can be attributed, in an octahedral [24,25] model, to the three spin allowed transitions, 3 A 2g ?…”

“…These bands show a shift of ±11-18 nm upon complexation, indicating coordination of the azomethine and hydrazide nitrogen atoms in all the complexes. [Co 2 L 1 (l-Cl)Cl 2 (H 2 O) 2 ]ÁH 2 O shows a well-resolved, medium-intensity band at *500 nm, in good agreement with octahedral Co II [22,23]. Charge transfer bands were present at 423 and 348 nm.…”

X-Ray Studies and Antibacterial Activity in Copper and Cobalt Complexes With Imidazole Derivative Ligands

“…4,5 Cobalt(II) ion is another important component in biological systems, since it is an essential micro nutrient for all living organisms. It is present in vitamin B 12 , which is involved in the production red of blood cells. 6 Another reason for the interest in transition metals and their complexes is their potential use as drugs and diagnostic agents to treat a variety of diseases.…”

“…Many inorganic complexes show antitumor and antibacterial activity. [7][8][9][10][11][12] There are numerous copper(II) compounds that present biological activity as antiinflammatory, anticonvulsive, antifungal, antibacterial, and antimicrobial agents. [13][14][15][16][17][18] An example is the trans-bis(acetate)bis(imidazole)copper(II) complex, which exhibits the strongest antitumor activity against the mouse melanoma cancer cell line B16.…”

Synthesis, structure analysis, anti-bacterial and in vitro anti-cancer activity of new Schiff base and its copper complex derived from sulfamethoxazole

“…The band at 26,525cm −1 can be assigned to n → π* (imine) transition. 26 The peak that appears at 22,500cm −1 is assigned to the transition 2 E 1g → 2 T 2g confirms octahedral geometry (figure 1). 27 The packing view of the octahedral complex is in figure 2.…”