Di‐μ‐acetato‐O:O′‐di‐μ‐acetato‐O,O′:O′‐bis­{[(cyclo­penta­dienyl)tris­(di­methyl­phosphito‐P)­cobalt‐O,O′,O′′]neodymium(III)}

In the title compound, [{η⁵‐CpCo[P(O)(OMe)₂]₃}Nd(O₂CCH₃)₂]₂, with a centrosymmetric mol­ecule, each Nd atom has an eight‐coordination environment, surrounded by a tripodal {L_OMe = CpCo[P(O)(OMe)₂]₃} and four bridging acetato ligands. The coordination geometry around each Nd centre is described as a distorted square‐antiprism and the two different types of acetato ligands have μ‐O:O′‐ and μ‐O,O′:O′‐acetato coordination modes. The Nd—O distances are in the range 2.378 (4)–2.594 (5) Å and the Nd?Nd distance is 3.9913 (6) Å.     

Physicochemical and thermal studies of viscose rayon borate fiber and its carbon fiber

Nonhalogen compounds have been studied for improvements in the flameproofing property and toxicity of flame retardants. Borate compounds have properties of multifunctional smoke suppressants, flame retardants, and afterglow suppressants. In this study, borate was coupled onto the surface of viscose rayon felt. Coupling and carbonization were confirmed by attenuated total reflectance Fourier transform infrared (ATR FTIR). The initial carbonization temperature was certified with ATR FTIR, elemental analysis of carbon, and thermogravimetric analysis. In the carbonization step, all chemical groups of the surface of the viscose rayon felt degraded to the various gases. Moreover, the weight percentage of the carbon element increased with increasing carbonization temperature. Initial rapid thermal degradation temperatures of viscose rayon prepared at various temperatures increased with the increasing reaction temperature. The activation energy was calculated with the Freeman and Carroll method. The activation energy of borate‐coupled viscose rayon decreased much more than before coupling. However, the activation energy increased with the increasing carbonization temperature in the carbonization step. Viscose rayon borates showed higher limiting oxygen index (LOI) values and volumetric resistance rate values than viscose rayon phosphates. In this article, the relationship between the activation energy and LOI is studied. The synthesized viscose rayon borate is found to be highly effective as a flame retardant and electrically resistant. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3875–3883, 2001     

Synthesis and studies of chemical properties of arylthallium(III)bis(tetrafluoroborates)

Synthesis of arylthallium(III)bis(tetrafluoroborates) was carried out and their pyrolysis was studied. Synthetic procedure for preparation of fluoroaromatic compounds is developed.     

Influence of Diffusion on the Kinetics of an Enzyme-Catalyzed Reaction in Gelatin-Based Gels

The influence of mass-transport limitations on the initial reaction rates of a lipase-catalyzed stereoselective esterification reaction has been investigated for two structurally different gelatin-based gels. The time to reach equilibrium is much longer in pelleted hydrogels (pseudo-solid aqueous gels; PAGs) than in pelleted microemulsion-based gels (MBGs). R/S-(+/-)-2-Octanol and hexanoic acid were used as substrates. The reaction takes place by imbibition of the substrate-containing organic solvent into pores of the pelleted gel. To minimize the diffusion distances, the macroscopic surface areas of the gels were increased by granulating the gel pellets. The experimentally obtained initial reaction rates in granules were in good agreement with the theoretically obtained values from extrapolation to infinitely large areas. However, the still low initial reaction rates in the hydrogels compared to those in microemulsion-based gels cannot be explained by diffusion limitations. This finding was supported by the similar activation energies in both gels in granulated form. Changes in apparent molar standard enthalpy, entropy, and Gibbs energy for the activated complex formation were also estimated. The low reaction rate in hydrogels might thus be due to partial denaturation of the enzyme during the preparation step, to higher surface energy, or to the influence of a different solvent environment on the enzyme in these gels than in the microemulsion-based gels. Copyright 2001 Academic Press.     

Synthesis,characterization, and biological activity of Schiff bases metal complexes

The new Schiff base 1‐[(2‐{1‐[(dicyclohexylamino)‐methyl]‐1H‐indol‐3‐yl}‐ethylimino)‐methyl]naphthalen‐2‐ol (HL) was prepared from 1‐{[2‐(1H‐Indol‐3‐yl)‐ethylimino] methyl}‐naphthalen‐2‐ol and dicyclohexyl amine. From this Schiff base, monomeric complexes [M (L)_n (H₂O)₂ Cl₂] with M = Cr, Fe, Mn, Cd, and Hg were synthesized and characterized based on elemental analysis (EA), FT‐IR, mass(MS), UV‐visible, thermal analysis, magnetic moment, and molar conductance. The results showed that the geometrical structural were octahedral geometries for the Cr(III) and Fe(III) complexes, square planer for Pd(II) complex, and tetrahedral for Mn(II), Cd(II), and Hg(II) complexes. Kinetic parameters such as ΔE*,ΔH*, ΔG*, and K of the thermal decomposition stages were calculated from the TGA curves using Coats‐Redfern method. Additionally, density functional theory (DFT) was applied for calculations of both electronic structure and spectroscopic properties of synthesized Schiff base and its complexes. The analysis of electrostatic potential (EPS) maps correlates well with the computed energies providing on the dominant electrostatic nature of N‐H‐‐‐O interactions. The biological activities had been tested in vitro against Staphylococcus aureus, Pseudomonas aeruginosa, as well fungi like Penicillium expansum, Fusarium graminearum, Macrophomina phasealina, and Candida albicans bacteria in order to assess their antimicrobial potential.     

红外光曝露对于大鼠组织影响的傅里叶变换红外光谱研究

生物组织受到外界电磁场曝露以后,生物分子的结构可能会发生变化,所发生的变化可以从组织的红外光谱的变化得到确认。为了研究红外光曝露对血液、睾丸以及脑组织的影响,对曝露于红外光条件下30天的大鼠的血液、睾丸和脑组织进行了红外光谱测量,将测试结果在1 700～1 000 cm-1范围内与对照组进行了对比,并利用红外光谱的二阶导数谱进一步分析红外光曝露对生物各组织微观结构特性的影响,探讨了红外光曝露的作用位点及其机制。研究结果表明红外光曝露可致大鼠组织的红外光谱特征发生一定的变化,傅里叶变换红外光谱技术可以用于分析红外光曝露对于生物组织微观结构的影响及其发生机制。     

钛表面FHAP涂层的电沉积制备及其FTIR特征研究

在含有Ca2+,PO3-₄和F-的电解液中,用电化学恒电流方法,在工作电流为0.9 mA温度为60 ℃的条件下沉积60 min,在医用钛(Ti)表面上制得含氟羟基磷灰石(FHAP)涂层。采用扫描电镜(SEM)、能量弥散X射线谱(EDS)、X射线衍射(XRD)对涂层进行表征,用傅里叶变换红外光谱(FTIR)考察了氟离子的引入对涂层构象和生物活性的影响。结果表明：氟部分取代磷灰石中的羟基,FHAP晶格常数变小,涂层相貌由疏松的微米级的菊花瓣状变化为致密的纳米级的尖锥状。FTIR分析表明,涂层中羟基的伸缩和弯曲振动模式的对称性发生了改变,模拟体液浸泡后涂层覆盖碳磷灰石,涂层生物活性良好。     

Supramolecular self-assembly of new thiourea derivatives directed by intermolecular hydrogen bonds and weak interactions: crystal structures and Hirshfeld surface analysis

Research on Chemical Intermediates - We synthesized and characterized a series of four closely related thiourea derivatives (1–4) obtained by reaction of 4-R-benzoyl chloride (R: H, Cl, CH3,...