Qiang-Guo Li

Synthesis, crystal structure and biological properties of a bismuth(III) Schiff-base complex

In this paper, a new bismuth(III) Schiff-base complex [Bi9O8(vanen)3(NO3)2(CH3OH)2(H2O)]·3NO3·5.5H2O was synthesized by reaction of [H2vanen = N,N′-ethylene bis(3-methoxysalicylideneimine)] and Bi(NO3)3·5H2O in methanol at 45–60 °C. The inhibitory effects of the complex and its ligand on Schizosaccharomyces pombe (S. pombe) growth were investigated by microcalorimetry. The experimental results indicated the complex had a stronger inhibitory activity towards S. pombe than that of the ligand. The interaction between bovine serum albumin (BSA) and the complex under physiological conditions was studied by fluorescence spectroscopy. The complex had a quite strong ability to quench the fluorescence of BSA and their combination reactions were a static quenching process. The complex could bind BSA via a binding site and the binding distance r was 3.52 nm. The synchronous fluorescence spectroscopy further revealed that the complex had partly inserted into the hydrophobic pocket of BSA.

Synthesis of nordihydroguaiaretic acid derivatives and their bioactivities on S. pombe and K562 cell lines

Nordihydroguaiaretic acid (NDGA) and its synthetic analogues are potentially useful in treating diseases related to cancers, diabetes, viral and bacterial infections, and inflammation. In this paper, we report the optimal synthetic methods and the bioactivity study of terameprocol 2, NDGA derivative 3, and its cyclized analogue 4. The IC50 of these three compounds 2, 3 and 4 on the growth metabolism of Schizosacchromyces pombe and K562 cell lines were determined by microcalorimetry. The preliminary results showed that the compounds 2, 3 and 4 possessed good inhibition activities on S. pombe and K562 cell lines, and exhibited bidirectional biological effect and Hormesis effect. In particular, terameprocol 2 was found to possess the most potent inhibitory effect on K562 cell lines.

Thermochemical Study on Coordination Complex of Samarium with Salicylic Acid and 8-Hydroxyquinoline

Abstract The coordination complex Sm(C7H5O3)2·(C9H6NO), synthesized from the reaction of samarium chloride six-hydrate with salicylic acid and 8-hydroxyquinoline, was characterized with IR, elemental analysis, molar conductance, and thermogravimatric analysis. The standard molar enthalpies of solution of [SmCl3·6H2O (s)], [2C7H6O3 (s), [C9H7NO(s)] and [Sm(C7H5O3)2·(C9H6NO)(s)] in the calorimetric solvent were determined with the solution-reaction isoperibol calorimeter at 298.15 K to be ΔsHΘm[SmCl3·6H2O (s), 298.15 K] = −103.98 ± 0.04 kJ·mol−1, ΔsHΘm [2 C7H6O3 (s), 298.15 K] = 16.35 ± 0.14 kJ·mol−1, ΔsHΘm[C9H7NO (s), 298.15 K] = −6.11 ± 0.08 kJ·mol−1 and ΔsHΘm[SmC7H5O3)2·(C9H6NO) (s), 298.15 K] = −130.08 ± 0.04 kJ·mol−1, respectively. The enthalpy was determined to be ΔrHΘm = 89.59 ± 0.18 kJ·mol−1 for the reaction SmCl3·6H2O(s) + 2C7H6O3(s) + C9H7NO(s) = Sm (C7H5O3)2·(C9H6NO) (s) + 3HCl(g) + 6H2O(1). According to the above results and the data given in literature and through Hess′ law, the standard molar enthalpy of formation of Sm(C7H5O3)2·(C9H7NO)(s) was estimated to be ΔrHΘm[Sm(C7H5O3)2·(C9H6NO)(s), 298.15 K] = −2055.9 ± 3.03 kJ·mol−1.

Synthesis, crystal structure and spectroscopic studies of bismuth(III) complex with 2-substituted benzimidazole ligands.

Reaction of BiCl3 with 2-(2-hydroxy-3-methoxyphenyl)benzimidazole (HL) in tetrahydrofuran (THF) under reflux gave mononuclear complex of formula [Bi(HL)2Cl3·H2O]. 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.

Synthesis and bioactivity of a novel bismuthoxide Schiff-base complex derived from Salen-like ligand and bismuth(III) nitrate

In this paper, a novel bismuthoxide Schiff-base complex [Bi9O8(vanen)3(NO3)2(CH3OH)2(H2O)·3NO3·5.5H2O](abbreviated as Bivanen) was synthesized with Salen-like ligand[H2vanen=N,N’-ethylene bis(3-methoxy-salicylideneimine)] and bismuth(III) nitrate. Its structure was characterized by IR spectra, NMR spectra and X-ray diffraction. In particular, the biology activities of the ligand and the complex against Schizosaccharomyces pombe (S. pombe) were studied using biological microcalorimetry. The metabolic thermogenic curves of S. pombe were measured at 32.00 °C. Then, some quantitative thermokinetic parameters of growth metabolism of S. pombe including the rate constant(k), inhibition ratio(I) and half inhibition concentration(IC50) were calculated. Experimental results showed that the k values of S. pombe decreased while I values of S. pombe increased with the increase of concentrations of the ligand and the complex. The IC50 of the ligand and the complex were found to be 0.067 and 0.037 mmol/L, respectively.