Coordination behaviour of N′¹,N′⁴-bis((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)methylene) succinohydrazide toward transition metal ions and their antimicrobial activities

Abstract

Complexes of Cu(II), Ni(II), Co(II), Mn(II), Zn(II) and Fe(III) with N 1 ,N 4 -bis((1,5-dimethyl-3-oxo-2-phenyl-2,3dihydro-1H-pyrazol-4-yl)methylene) succinohydrazide are reported and characterized using various analytical and spectroscopic techniques like 1 H NMR-, mass-, IR-, ESR-, UV-Vis. spectra, magnetic moment and molar conductivity measurements as well as elemental and thermal analyses. The ligand behaves as a dibasic hexadentate N 2 O 4 bonded covalency via the enolic carbonyl oxygen of hydrazide moiety and coordeinated via carbonyl oxygen of antipyrine moiety and azomethine nitrogen atoms. Based on magnetic and electronic spectra data a distorted octahedral geometry around the metal ions has been proposed. The ESR spectrum of copper(II) complexes (3) showed axial symmetry with g >g⊥>g e , indicating a distorted octahedral structure and presence of the unpaired electron in d (x2-y2) orbital. The antimicrobial activities results of the metal complexes 2, 3, 4, 5, 8, 11, 13 and 16 show that, all these complexes exhibit moderate to mild inhibitory effects aganist Bacillus subtilis, Escherichia Coli and Aspergillus niger while the parent ligand is inactive. This enhancement may be attrubied to their structures which possess an additional C=N bond. Moreover, coordination reduces the polarity of the metal ion mainly because of the partial sharing of its positive charge with the donor atom within the chelate ring system, which formed during the coordination. This process, in turn, increases the lipophilic nature of the central metal atom, which favors its permeation more efficiently through the lipid layer of the microorganism thus destroying them more aggressively.

Synthesis and Characterization of VO2+, Co2+, Ni2+, Cu2+ and Zn2+ Complexes of a Schiff base ligand derived from ethyl 2‐amino‐6‐ethyl‐4,5,6,7‐tetrahydrothieno[2,3‐c]pyridine‐3‐carboxylate and their Investigation as fungicide Agents

“…The presence of two new bands in the acetate complexes (3–4) and (6–7) in the 1531–1555 and 1339–1351 cm −1 are imputing to both the symmetric and asymmetric stretching band vibration of the acetate ion [(ν as (COO − ) and ν s (COO − ))]. The difference values (Δ) between ν as (COO − ) and ν s (COO − ) in (3–4) and (6–7) were in range 183–206 cm −1 implying to mono‐chelated acetate group . The sulfate complex (2) demonstrated bands at 1120, 1038 and 727 cm −1 distinctive for the mono‐chelated sulfate group, where the low conductance values of the compounds affirmed the later state…”

Synthesis and characterization of novel chromone Schiff base complexes as p53 activators

“…From a previous interest in the biological activity of both chromone and antipyrine moieties and in continuation of our effort to synthesize bioactive metal complexes, our goal in the work reported here was the preparation of a novel chromone Schiff base ligand and its complexes, and then to study the structure of the prepared compounds through elemental analysis and spectroscopic data. Moreover, we also studied the ability of these novel compounds to activate the tumour suppressor p53 in cancer cells.…”

Anti‐neurotoxic evaluation of synthetic and characterized metal complexes of thiosemicarbazone derivatives

“…The iron(III) complexes (7) and (17) gave magnetic moment value 5.6 and 5.65 BM respectively, compatible with high‐spin d 5 Fe(III) ion. The Fe(III) complexes (7) and (17) electronic spectra show bands at 500, 515 and 600, 615 nm assigned to 6 A 1g → 4 T 2g (G) and 6 A 1 (G)→ 4 T 1 (G) transitions respectively, assignable to octahedral Fe(III) (Figure ) .…”

“…Manganese(II) complex (8) shows only a weak and broad band at 760 nm corresponding to 6 A 1g → 4 T 1g and 6 A 1g → 4 T 2g transitions that are compatible with manganese(II) ion in an octahedral environment (Figure ) . However, the high intense charge transition tailing into the visible region, obscure the very weak d–d absorptions of the Mn(II) complexes . The electronic spectrum of manganese(II) complex (18) shows two bands at 660 and 585 nm, indicating that this complex has a square planar geometry (Figure ).…”