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A new bismuth(III) Schiff‐base complex [Bi2(HL)2(NO3)4(CH3OH)]•2CH3OH was prepared by reaction of the equivalent molar of Schiff‐base ligand [H2L = (E)‐N′‐(2‐hydroxy‐4‐methoxybenzylidene)isonicotinohydrazide] and Bi (NO3)3•5H2O with the assistance of mannitol. The complex was structurally characterized by elemental analysis, spectroscopic methods (FT‐IR, MS, 1HNMR, and 13CNMR) and single crystal X‐ray diffraction. The molecular structure of the complex reveals that the ligand forms a 1:1 complex with bismuth(III) ion. It is composed of two 7‐coordinated bismuth(III) ions, two tetradentate O2N‐donor ligands, four nitrate ions, and three methanol molecules. The complex and its free ligand were evaluated against gram‐positive bacteria (Staphylococcus aureus, Bacillus subtilis) and gram‐negative bacteria (Escherichia coli, Pseudomonas aeruginosa). The complex was more active than the ligand against all bacterial strains. Their cytotoxic activity was also investigated against SNU‐16 cell. The complex is approximately three times more potent than the ligand, with the IC50 values 0.35 and 1.18 μM for the complex and its ligand, respectively. [ABSTRACT FROM AUTHOR]

A new bismuth(III) Schiff‐base complex [Bi2(HL)2(NO3)4] was synthesized by using equivalent molar of Schiff‐base ligand [H2L = (E)‐N′‐(2‐hydroxy‐3‐methoxybenzylidene)isonicotinohydrazide] and Bi(NO3)3•5H2O with the assistance of Mannitol. The complex was structurally characterized by elemental analysis, spectroscopic methods, and single crystal X‐ray diffraction. The experimental and theoretical vibrational bands (infrared and Raman spectra) have been discussed. The antimicrobial activity of the complex against Schizosaccharomyces pombe was evaluated by bio‐microcalorimetry at 32°C. Some thermokinetic parameters (k, Pmax, tG, and Qtotal) were obtained from the metabolic power–time curves of S. pombe, and their quantitative relationships with the concentration (c) were discussed. The half inhibition concentrations (IC50) of isoniazid, Schiff base, and the complex were calculated. The complex showed the strongest inhibition effect among three compounds. [ABSTRACT FROM AUTHOR]

Four dinuclear bismuth(III) Schiff-base complexes bearing Schiff-base ligands have been synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analysis, and spectral techniques (FT-IR, NMR and MS). The analytical data reveal the bismuth(III) complexes possess 1:1 metal–ligand ratios. In vitro biological studies have revealed that bismuth(III) complexes displayed much higher antibacterial and antitumor activities than their parent ligands, which involves two gram-negative (S. aureus , B. subtili) and two gram-positive (E. coli , P. aeruginosa) bacteria, and human gastric cancer SNU-16 cells. The power–time curves of S. pombe exposed to tested compounds were detected by bio-microcalorimetry. Some thermokinetic parameters (k , P max, t G and Q total) were derived based on the metabolic power–time curves, and their quantitative relationships with the concentrations (c) were further discussed. Four dinuclear bismuth(III) Schiff-base complexes have been synthesized and characterized. The complexes possess 1:1 metal–ligand ratios and display much higher bioactivities than the ligands. Five thermokinetic parameters (k , P max, t G and Q total) were derived by the power–time curves and their quantitative relationships with the concentrations (c) were discussed. [Display omitted] • Four dinuclear Bismuth(III) Schiff-base complexes were designed and synthesized. • Upon coordination to Bi(III) antibacterial and antitumor activities increased. • Five thermokinetic parameters (k , I , P max , t G and Q total) were derived. • The complex bearing halide group display more potent biological activities. [ABSTRACT FROM AUTHOR]

Reaction of BiCl 3 with 2-(2-hydroxy-3-methoxyphenyl)benzimidazole (HL) in tetrahydrofuran (THF) under reflux gave mononuclear complex of formula [Bi(HL) 2 Cl 3 ·H 2 O]. The binding interaction of the complex with bovine serum albumin (BSA) was investigated using the fluorescence quenching method. The experimental results showed that the complex could bind to BSA in the proportion of about 1:1. The binding reaction was spontaneous and hydrophobic force played major role in the reaction. The binding of the complex to BSA could change the microenvironment and conformation of BSA. [ABSTRACT FROM AUTHOR]