Rapid synthesis and characterization of silicon substituted nano hydroxyapatite using microwave irradiation

Nano sized hydroxyapatites with silicon substitution of three different silicon concentrations were successfully prepared first time by a rapid microwave assisted synthesis method, with a time saving and energy efficient technique. The effects of the Si substitution on crystallite size, particle size and morphology of the powders were investigated. The crystalline phase, microstructure, chemical composition, and morphology and particle size of hydroxyapatite and silicon substituted hydroxyapatites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and dynamic light scattering. The crystallite size and particle size decreases with increase in silicon content and particle morphology spheroidal for pure hydroxyapatite changes to elongated ellipsoidal crystals while silicon substitution increases. Fourier Transform Infrared Spectroscopy analysis reveals, the silicon incorporation to hydroxyapatite lattice occurs via substitution of silicate groups for phosphate groups. Substitution of phosphate group by silicate in the apatite structure results in a small increase in the lattice parameters in both a-axis and c-axis of the unit cell.     

黄酮甙类化合物中的酰基取代及其取代位置的确定

研究了黄酮甙类化合物的酰基取代现象，借助２ Ｄ ＮＭＲ技术，举例研究了一黄酮醇三乙酰基三糖甙的结构，着重研究糖上酰基的取代位置，并归纳总结了黄酮甙类化合物中各种常见的酰基的＾１３ ＣＮＭＲ谱及其取代所产生的位移现象。     

Kinetics ofEDTA substitution of N,N′-ethylenedisalicylamidato cuprate(II) in alkaline media

Summary The kinetics ofEDTA reaction with N,N-ethylenedisalicylamidato cuprate(II) is followed at 30°C in borate buffer and is found to be first order in each reactant. The reaction ispH dependent and involves protonation of a deprotonated peptide nitrogen followed by nucleophilic attack byEDTA.

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Kinetik derEDTA-Substitution von N,N-Ethylendisalizylamidatokupfer(II) in alkalischem Medium (Kurze Mitt.)

Zusammenfassung Die Kinetik derEDTA-Reaktion mit N,N-Ethylendisalizylamidatokupfer(II) wurde bei 30°C in Borat-Puffer verfolgt. Es wurde erste Ordnung bezüglich jedes Reaktanden festgestellt. DiepH-abhängige Reaktion beinhaltet die Protonierung eines deprotonierten Peptid-Stickstoffs, gefogt von einem nucleophilen Angriff einesEDTA-Moleküls.

     

有机磷化合物的质谱研究(Ⅵ)——磷酰二胺酯类化合物的电子轰击质谱和化学电离质谱

本文报道了7种新的N-烷基-N′-乙氧羰基甲基-N′-芳磺酰基-O-乙基磷酰二胺酯化合物的电子轰击质谱(EIMS)和化学电离质谱(CIMS,甲烷为反应气)。结果表明,无论是EIMS,还是CIMS均存在较多的骨架重排离子峰;取代基对谱图有较大的影响;EIMS中P—N键的断裂为重要质谱特征,CIMS中MH~+准分子离子为重要特征离子,还存在分子离子反应的产物。     

Investigation of the kinetics of formation of 1 : 1 complex between chromium(III) with 1,3-propanediamine-N,N′-diacetate-N,N′-di-3-propionate ion in aqueous acidic media

The kinetics of formation of the 1?:?1 complex of chromium(III) with 1,3-propanediamine-N,N′-diacetate-N,N′-di-3-propionate (1,3-pddadp) were followed spectrophotometrically at λ _max?=?557?nm. The reaction was first-order in chromium(III). Increasing the 1,3-pddadp concentration from 2.2?×?10^?2 to 0.11?mol?dm^?3 accelerated the reaction rate. Increasing the hydrogen ion concentration from 1.995?×?10^?5 to 6.31?×?10^?4 mol?dm^?3 retarded the reaction rate. The reaction rate was also retarded by increasing ionic strength and dielectric constant of the reaction medium. A mechanism was suggested to account for the results obtained which involves ion-pair formation between the various reactants. Values of 22?kJ?mol^?1 and ?115?J?K^?1 mol^?1 were obtained for the energy and the entropy of activation, respectively, which indicate an associative mechanism. The logarithm of the formation constant of the 1?:?1 complex formed was 11.3.     

Synthesis of thieno[3,4-d]-1,3-dithiol-2-one derivatives

A series of mono-substituted and bis-substituted derivatives of thieno [3,4-d]-1,3-dithiol-2-one were prepared through halogenation, chloromethylation, and subsequent nucleophilic substitution reactions. Compounds were characterized by NMR, FT-IR, and HRMS.     

Characteristic and spectroscopic properties of the Schiff-base model compounds

Two series of conjugated aromatic imines (Schiff-base model compounds) with different central groups and various side-group substitutions have been synthesized and characterized by elemental analysis, differential scanning calorimetry (DSC) technique, hydrogen nuclear magnetic resonance (¹H NMR), Fourier transform infrared (FTIR) and ultra-violet and visible light (UV–vis) spectroscopy measurements. The UV–vis absorption of solutions of these compounds in dimethylacetamid (DMA), chloroform and methanol was investigated in the optical range from 240 to 450 nm, where two distinct absorption bands: at 250–280 and 315–360 nm with the different level of absorption have been observed. The influence of compound molecular structure and polarity of solvent on the absorption spectra and the possible optical transitions have been discussed. Structure of diamines in the azomethine models fundamentally affected their spectroscopic properties and conjugation of π-electrons.