Structure and magnetic properties of diaqua(4,4′-bipyridine) terbium(III) and the zinc(II) carboxylate dimer [Tb2Zn2(CH2C(CH3)COO)10(bipy)(H2O)2]2

A novel heteronuclear complex, [Tb₂Zn₂L₁₀(bipy)(H₂O)₂]₂ (HL = -methylacrylic acid, bipy = 4,4-bipyridine), was synthesized and characterized by elemental analysis and i.r. absorption spectra. Its structure, determined by X-ray diffraction, is a discrete octanuclear molecule, in which two Zn^II ions are linked by a bipy molecule and between Tb^III ions, or Tb^III and Zn^II ions are bridged by bidentate -methylacrylato groups. The temperature dependence of the magnetic susceptibility of the complex shows strong ferromagnetic interaction between the terbium atoms.     

Rearrangement of 5-trimethylsilylthebaine on treatment with L-selectride: an efficient synthesis of (+)-bractazonine

Treatment of 5-trimethylsilylthebaine with L-Selectride gave rise to a rearrangement to 10-trimethylsilylbractazonine through migration of the phenyl group, whereas treatment of thebaine with strong Lewis acids is known to lead to a similar rearrangement through migration of the alkyl bridge to give, after reduction, (+)-neodihydrothebaine. It is suggested that the rearrangement of the alkyl group of thebaine is favored due to the formation of a tertiary benzylic cation. However, for 5-trimethylsilylthebaine, the lithium ion of L-Selectride acts as the Lewis acid and the beta-silyl effect dominates in the stabilization of any positive charge. This rearrangement provides a clear example of the greater relative migratory aptitude of phenyl groups over alkyl groups, and provides an efficient synthesis of (+)-bractazonine from thebaine.     

Detection of synergistic effect of superoxide dismutase and jujubosides on scavenging superoxide anion radical by capillary electrophoresis

A new capillary electrophoresis method was developed to study the synergistic effect of superoxide dismutase and jujuboside A or B on scavenging superoxide anion radical in serum matrix respectively, in which superoxide anion radical was generated from pyrogallol autoxidation. The electrophoresis conditions, and the factors affecting the productive rate of purpurogallin, such as pyrogallol autoxidation product and the activity of superoxide dismutase, were optimized. Under optimal conditions, the content of superoxide dismutase in Gibco newborn calf serum was 7.06 mg/L, RSD was 2.01% and the average recovery was 98.4%. The values of IC₅₀ for jujuboside A and B in the serum matrix were 157.67 and 31.60 mg/L respectively, and they both had synergy on scavenging superoxide anion radical with superoxide dismutase, but there was no the dose‐dependency on this synergy.     

In vitro anticomplementary activity and quality evaluation of dried blossoms of Inula nervosa Wall. from different geographical origins

Blossoms of Inula nervosa Wall. (BINW) are traditionally used as an analgesic and antitussive in China. In this study, in vitro anticomplementary activities of crude extract from BINW in 21 batches and of extracts of four monomeric compounds were evaluated by the classical pathway. The effect of the region of origin on the quality of BINW was evaluated by fingerprint analysis for the first time. Furthermore, chemometric methods including similarity analysis and principal component analysis were employed to evaluate the quality of BINW. The nine major monomeric compounds were quantitated by ultra‐high‐performance liquid chromatography. All nine analytes demonstrated excellent linearity with recoveries ranging from 97.25% to 102.76%. The limits of detection and quantification were 0.07–12.20 μg/mL and 0.22–40.27 μg/mL, respectively. Results indicate that different regions of origin have a significant effect on the quality of BINW. Fingerprint analysis in combination with chemometrics and multi‐ingredient determination is an efficient and reliable approach for quality evaluation. The BINW samples from Yunnan had the highest ratio of 1,5‐dicaffeoylquinic acid and thymol; they also exhibited significantly higher anticomplementary activity than those from three other areas. This study successfully established a rapid and efficient method to evaluate the quality and biological activity of BINW.     

Syntheses,Characterization, and Fluorescence Properties of Four Divalent Lead Coordination Polymers based on Zwitterionic Ligands

Four novel divalent lead coordination polymers based on a series of zwitterionic ligands, Pb₂Cl₄L₁ ( 1 ), [Pb₂Cl₄L₂]·2H₂O ( 2 ), Pb₂Cl₂(CH₃COO)₂L₂ ( 3 ), and Pb₃Cl₄(NO₃)₂L₃ ( 4 ) were solvothermally synthesized and successfully characterized. Single crystal structure studies reveal that compound 1 is a chain structure based on the inorganic “PbCl₂” chain motif, whereas compounds 2 – 4 are sheet structures each constructed by inorganic “PbCl₂”, “PbCl(CH₃COO)”, and “Pb₃Cl₄” chain motifs. Hydrogen bonding interactions in term of C–H ··· Cl and C–H ··· O play a key role to form supramolecular 3D structures of 1 – 4 . Additionally, studies of solid state fluorescence indicate 1 – 4 emit in the ultraviolet and visible region that can be assigned to the inter‐ligand π*–π and/or π*–n transitions.     

A New Planar Hexanuclear Dysprosium Cluster Exhibiting Slow Magnetic Relaxation Features

Reaction of the Schiff base ligand H₂L and dysprosium acetate result in a new planar Dy₆ cluster [Dy₆(μ₃‐OH)L₆(Ac)₆] · MeOH ( 1 ) [H₂L = N'‐(2‐hydroxybenzylidene)‐2‐(hydroxyimino)propanohydrazide, HAc = acetic acid], which was successfully structurally and magnetically characterized. Single‐crystal X‐ray diffraction analysis revealed that 1 contained a hexanuclear dysprosium cluster [Dy₆], which is composed of four Dy₃ triangular units. Magnetic measurements suggest that 1 displays single‐molecule magnet (SMM) behavior which is enhanced by applying a 4000 Oe direct‐current field. The effective anisotropic barrier U_eff/k_B = 14.9 K and the pre‐exponential factor τ₀ = 1.31 × 10^–6 s are also obtained. This work may provide more insights for the design and investigation of lanthanide‐based SMMs.     

Highly Sensitive and Selective Fluorescence Probe for 2,4‐Dinitrophenylhydrazine Detection in Wastewater Using Water‐Soluble CdTe QDs

A simple, cheap, sensitive and selective probe for determination of DNPH in wastewater using thioglycolic acid (TGA)‐coated CdTe QDs (TGA‐QDs) as fluorescence probe has been established, and the properties of CdTe QDs were characterized by TEM, FT‐IR, DLS, XRD and zeta potentials. CdTe QDs fluorescence is highly efficiently quenched after adding DNPH on account of electron transfer effect, and the fluorescence quenching behavior of CdTe QDs interaction with DNPH is static quenching process. A good linear relationship is observed between the relative fluorescence intensity (F₀/F) and 0.06–10 ng mL^?1 of DNPH. As compared with some of reported methods, LOD of this method for analysis of DNPH (0.23 ng mL^?1) is the lowest. Masking agents of DDTC and NH₄OH can eliminate the interference of Cu²⁺, Ag⁺ and Hg²⁺. Hence, DNPH can be selectively and accurately detected and the established method was successfully used for detecting DNPH in wastewater with acceptable recovery of 90.6–102%.     

Characterization of the chemical constituents in Hongjingtian injection by liquid chromatography quadrupole time‐of‐flight mass spectrometry

Hongjingtian injection is made from Rhodiola wallichiana and used in the treatment of stable angina pectoris associated with coronary heart disease. In this study, the chemical constituents in Hongjingtian injection were comprehensively studied using liquid chromatography quadrupole time‐of‐flight mass spectrometry. A total of 49 compounds were identified or assumed, including 10 organic acids, nine phenylethanoids, 10 phenylpropanoids, two flavonoid glycosides, seven monoterpene glycosides, seven octylglycosides and four other types of compounds. The structures of seven compounds were confirmed by comparing their retention times, MS and UV spectra with the corresponding authentic standards. Amongst the 49 compounds, 35 were firstly found in R. wallichiana, while they have been reported in other species of the genus Rhodiola, including Rhodiola crenulata, Rhodiola sacra, Rhodiola rosea and Rhodiola kirilowii. The possible fragmentation pathways in the mass spectrometry of the major types of compounds are proposed and summarized. Our study demonstrates a rapid method for characterizing the chemical constituents present in the Hongjingtian injection, which could also be applied to the identification of chemical constituents in other TCM formulae containing R. wallichiana.     

Adsorption of Th(IV) from aqueous solution by the graphene oxide nanoribbons/chitosan composite material

Journal of Radioanalytical and Nuclear Chemistry - In order to reduce the potential toxicity to the environment after treatment of radioactive waste water, an eco-friendly graphene oxide...