Molecular structure of potassium [N,N′-bis(salicylideneamino)nitroguanidonate-N,N′,-O,O′]nickel(ii), the product of condensation of (salicylideneamino)nitroguanidine with salicylaldehyde on a Ni2+ ion template

The crystal structure of the product of the condensation of (salicylideneamino)nitroguanidine with salicylaldehyde on a Ni²⁺ ion template, K[Ni(C₁₅H₁₀N₅O₄)] · DMF, has been studied. It was established that a planar Ni complex, consisting of isolated [NiL]^– anions and solvated [K⁺ · DMF] cations, is formed. The negative charge of the anion is localized mainly on the O atoms of the nitro group. The nitroguanidine fragment of the ligand occurs in the tautomeric form, which was not reported previously.Deceased in 1995Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2273–2277, September, 1996.     

Ar原子电离能谱和Ar3p电子动量谱研究

电子动量谱学（ElectronMomentumSPectroscoP则是近．二十年来发展起来的一种新兴的探测原子、分子和固体结构的手段，它不仅能够获得轨道结合能的信息，而且能够能壳分辨地得到轨道电子的动量分布（即动量表象中的波函数模方）；同时它还是研究电子关联的最有效的实验手段．其     

Molecular Structure of 1,3,5-Tris (Trimethylstannyl) Benzene: An Electron Diffraction Study

The molecular structure of 1,3,5-tris (trimethylstannyl) benzene has been determined by gas-phase electron diffraction. The C — C bond length is in good agreement with that in benzene. In agreement with the somewhat electron-releasing character of the substituents, the endocyclic bond angles at the substituents are somewhat smaller than 120°. The mean value of Sn — C bond lengths is greater than that in tetraphenyltin and tetramethyltin. The SnMe₃ groups appear freely rotating around the C_aryl — Sn bonds. The following bond lengths (r _g) and bond angles were determined: (Sn — C)_mean 2.150 ± 0.007 Å, C — C 1.399 ± 0.005 Å, (C — H)_mean 1.105 ± 0.006 Å, < C — C(Sn) — C 117.7 ± 1.7º, < C_aryl — Sn — C_methyl 106.7 ± 0.7º < Sn — C — H 111.5 ± 0.9º.     

A study on the bioactivity of chitosan/nano-hydroxyapatite composite scaffolds for bone tissue engineering

In order to increase the biocompatibility and bioactivity of chitosan, hydroxyapatite had been in situ combined into chitosan scaffolds. The bioactivity of the composite scaffolds was studied by examining the apatite formed on the scaffolds by incubating in simulated body fluid and the activity of preosteoblasts cultured on them. The apatite layer was assessed using scanning electronic microscope (SEM), X-ray diffraction (XRD), Fourier-Transformed Infrared spectroscopy (FTIR) and weight measurement. Composite analysis showed that after incubation in simulated body fluid on both of the scaffolds carbonate hydroxyapatite was formed. With increasing nano-hydroxyapatite content in the composite, the quantity of the apatite formed on the scaffolds increased. Compared with pure chitosan, the composite with nano-hydroxyapatite could form apatite more readily during the biomimetic process, which suggests that the composite possessed better mineralization activity. Furthermore, preosteoblast cells cultured on the apatite-coated scaffolds showed different behavior. On the apatite-coated composite scaffolds cells presented better proliferation than on apatite-coated chitosan scaffolds. In addition, alkaline phosphatase activities of cells cultured on the scaffolds in conditioned medium were assessed. The cells on composite scaffolds showed a higher alkaline phosphatase activity which suggested a higher differentiation level. The results indicated that the addition of nano-hydroxyapatite improved the bioactivity of chitosan/nano-hydroxyapatite composite scaffolds. On the other hand, that is to say composition of substrates could affect the apatite formation on them, and pre-loaded hydroxyapatite can enhance the apatite-coating. It will also be significant in preparation of apatite-coating polymer scaffolds for bone tissue engineering.     

Highly tilted antiferroelectric (R) enantiomers useful for the formulation of eutectic mixtures

ABSTRACT

Novel chiral three-ring (R) enantiomers were synthesised using optically active (R)-(?)-2-octanol. Properties, such as the sequence of phases, the transition temperatures and enthalpies, were tested by a polarising optical microscope and differential scanning calorimeter. An antiferroelectric smectic phase (SmC_A*) with a direct transition from the antiferroelectric to the isotropic phase (SmC_A*-Iso) was observed for three esters with an achiral C₃F₇CH₂O(CH₂)₃O– terminal chain. Bi- and multicomponent mixtures with a broad temperature range of the antiferroelectric phase and good electro-optical properties were formulated. Helical pitch of pure esters and mixtures was measured by spectrophotometry method.     

ICP-AES法测定锌阳极中的铝、镉、铁、铜、铅

通过分析高频功率、雾化压力、辅助气流量和泵速等试验条件，建立了ICP-AES法测定锌阳极中铝、镉、铁、铜、铅的方法。用该方法测定锌阳极中的铝、镉、铁、铜、铅，其RSD分别为0.17%、0.63%、2.7%、5.2%、2.5%，回收率分别为99.3%-101.2%，99.3%-100.3%、97.1%-102.2%、97.8%-102.9%。对锌阳极试样进行测定，该方法的测定结果与GB4951-85方法的测定结果基本一致。     

Zur Synthese von fungizid wirksamen Isocamphanderivaten: Synthesen in der Isocamphanreihe, 34. Mitt.

Summary Some esters of isocamphenilanic acid (4) have been prepared and tested for their fungicidal and insecticidal activity. Esters of various acids with isocamphanyl ethylalcohol (5) have also been synthesized and included in the fungicidal/acaricidal/insecticidal screening programme. All esters bear a geminal dimethyl group at C-3 of the bicyclus which is important because of its shielding effect.

     

Synthesis of Sulfur-Containing Bis-Terpenoids Based on Monoterpene Oxides

Ethanedithiol and di(mercaptoethyl)sulfide react regio- and stereoselectively with (+)-3-carene and -hydroxy(-)--pinene -oxides in the presence of sodium ethoxide to give the corresponding bis- and tris-sulfides with two terpene fragments     

Crystallization behavior and biodegradation of poly(3-hydroxybutyrate) and poly(ethylene glycol) multiblock copolymers

Block copolymerization by using isocyanates is an effective method for incorporating PHB and PEG because it can prepare copolymers with good properties, such as toughness, strength, and so on. In this study, we adopted soil suspension system to estimate the biodegradability of a series of PHB/PEG multiblock copolymers with different compositions and block lengths. In the degradation process, the changes in weight loss, molecular weight, and tensile strength were periodically measured to determine the biodegradability, and the surface morphology was also observed by SEM. In contrast to pure PHB, the weight loss of the copolymer was relatively lower. On the other hand, the tensile strength and molecular weight experienced apparent decrease, and for BHG1000-3-1, they reached 46.7% and 77.7% of the initial value, respectively. SEM observation showed that the surface was covered with numerous erosion pits. All these indicate that the degradation indeed took place and long-chain molecules have been hydrolyzed into shorter ones. The crystallization behavior was also investigated by DSC and WAXD. The results showed that both the segments, PEG and PHB, can form crystalline phases at lower PHB contents ranging from 29% to 44%, and when PHB component was more than 60%, only PHB phase can crystallize.