X-ray spectroscopic study of the thiomalic acid complex of cobalt

The cobalt K absorption spectrum has been studied in thiomalic acid complex of cobalt using a bent crystal X-ray spectrograph. It has been observed that the position of the absorption discontinuity taken with the freshly prepared complex differs from that of the discontinuity obtained with the complex kept in air for about 24 hours. It has been shown that this shift of the absorption edge is due to the change in valency of cobalt in the complex. The shape of the absorption discontinuity has revealed that the complex has an octahedral structure with the hybridizationsp ³ d ². On the molecular orbital theory the electronic configuration in this complex can be described asa _1g ^Emphasis>2 t _1u ^Emphasis>6 e _g ^Emphasis>4 t _2g ^Emphasis>4 e _g ^Emphasis>*2 .     

Modification of Lytle’s theory: Interpretation of the extended fine structure associated with LIII absorption discontinuity of some ytterbium systems

In Lytle’s theory for the extended fine structure in x-ray absorption spectra, the potential at the boundary of the ‘equivalent sphere’ around the absorbing atom, having volume equal to that of the Wigner-Seitz cell is considered to be infinite. It has been observed that Lytle’s theory is applicable only in the case of metals and metallic systems. In the present paper the extended fine structure associated with the L_III absorption spectra of some systems of ytterbium is interpreted on the basis of Lytle’s model, modified by using a finite potential instead of an infinite one at the boundary of the equivalent sphere. The values of this potential are estimated for eight systems of ytterbium. It has been shown that there exists a correlation between the potentials and covalency of the compounds.     

Improved synthesis of monohydroxytriphenylenes (MHTs)—important precursors to discotic liquid crystal families

Monohydroxypentaalkoxytriphenylenes are important intermediates for elaboration into complex covalently linked discotic liquid crystal assemblies. An improved, simple synthetic protocol is described that gives rapid access to these precursors in a single step.     

Temperature-dependent structure of methyltributylammonium bis(trifluoromethylsulfonyl)amide: X ray scattering and simulations

We report the combined results of computational and x ray scattering studies of amorphous methyltributylammonium bis(trifluoromethylsulfonyl)amide as a function of temperature. These studies included the temperature range for the normal isotropic liquid, a deeply supercooled liquid and the glass. The low q peaks in the range from 0.3 to 1.5 A(-1) in the structure function of this liquid can be properly accounted for by correlations between first and second nearest neighbors. The lowest q peak can be assigned to real space correlations between ions of the same charge, while the second peak arises mostly from nearest neighbors of opposite charge. Peaks at larger q values are mostly intramolecular in nature. While our simulated structure functions provide an excellent match to our experimental results and our experimental findings agree with previous studies reported for this liquid, the prior interpretation of the experimental data in terms of an interdigitated smectic A phase is not supported by our simulations. In this work, we introduce a set of general theoretical partitions of real and reciprocal space correlations that allow for unambiguous analysis of all intra- and interionic contributions to the structure function and coherent scattering intensity. We find that the intermolecular contributions to the x ray scattering intensity are dominated by the anions and cross terms between cations and anions for this ionic liquid.     

Synthesis and liquid crystal properties of triphenylene liquid crystals bearing polymerisable acrylate and methacrylate groups

The synthesis and liquid crystalline properties of some new triphenylene discotics bearing pendant acrylate groups are described. Mesophase behaviour is found to be sensitive to the number and position of substituents, the linking chain length, and to change between acrylate and methacrylate termini. Investigation of the isomerically pure triphenylene acrylate and methacrylate derivatives showed that the molecular symmetry also has a modest effect on mesophase behaviour. Unsurprisingly columnar phases are formed only when all substituent chains are of comparable length and methacrylates are far superior to simple acrylate termini, probably due to favourable space filling in the mesophase.     

Analgesic and Anticancer Activity of Benzoxazole Clubbed 2-Pyrrolidinones as Novel Inhibitors of Monoacylglycerol Lipase

Ten benzoxazole clubbed 2-pyrrolidinones (11–20) as human monoacylglycerol lipase inhibitors were designed on the criteria fulfilling the structural requirements and on the basis of previously reported inhibitors. The designed, synthesized, and characterized compounds (11–20) were screened against monoacylglycerol lipase (MAGL) in order to find potential inhibitors. Compounds 19 (4-NO₂ derivative) and 20 (4-SO₂NH₂ derivative), with an IC₅₀ value of 8.4 and 7.6 nM, were found most active, respectively. Both of them showed micromolar potency (IC₅₀ value above 50 µM) against a close analogue, fatty acid amide hydrolase (FAAH), therefore considered as selective inhibitors of MAGL. Molecular docking studies of compounds 19 and 20 revealed that carbonyl of 2-pyrrolidinone moiety sited at the oxyanion hole of catalytic site of the enzyme stabilized with three hydrogen bonds (~2 Å) with Ala51, Met123, and Ser122, the amino acid residues responsible for the catalytic function of the enzyme. Remarkably, the physiochemical and pharmacokinetic properties of compounds 19 and 20, computed by QikProp, were found to be in the qualifying range as per the proposed guideline for good orally bioactive CNS drugs. In formalin-induced nociception test, compound 20 reduced the pain response in acute and late stages in a dose-dependent manner. They significantly demonstrated the reduction in pain response, having better potency than the positive control gabapentin (GBP), at 30 mg/kg dose. Compounds 19 and 20 were submitted to NCI, USA, for anticancer activity screening. Compounds 19 (NSC: 778839) and 20 (NSC: 778842) were found to have good anticancer activity on SNB-75 cell line of CNS cancer, exhibiting 35.49 and 31.88% growth inhibition (% GI), respectively.     

Dichiral [4.4.3.01,5]tridecane copper(II) cluster derived from a tripodal ligand having unsymmetrical podands and the linker: Synthesis,structure, surface grafting and catalytic aspects

Pseudo‐atranes have a significant role in catalysis; however, obtaining chiral pseudo‐atranes for covalent functionalization of heterogeneous catalytic surfaces is very challenging. Herein, synthesis of a chiral tripodal amine [N{CH (CH₂Ph)CH₂OH}{CH₂(4? Br? C₆H₃OH)}{CH₂(2? CHO? 4? Me? C₆H₂OH)}] ( 1 ) and a dichiral [4.4.3.0^1,5]tridecane copper(II) cluster, that is, (Cu[N{CH (CH₂Ph)CH₂OH}{CH₂(4? Br? C₆H₃O)}{CH₂(2? CHO? 4? Me? C₆H₂O)}])₂ ( 2 ) is described. The compounds are characterized by elemental analyses, Fourier transform infrared (FT‐IR) spectroscopy, mass spectrometry and single‐crystal X‐ray crystallography (for 2 ). The compound 2 is the first example of chiral pseudo‐copper(II)atrane in which three unsymmetrical arms (two phenolic and a chiral ethanolic arm) are fused via Cu? N transannular bond. The free ? CHO group present in one of the tricyclic arms of the 2 is tested as a linker to load it on 3‐aminopropyltriethoxysilane‐functionalized magnetic nanosilica for catalytic applications. The loading of 2 on magnetic nanosilica through ? CHO was confirmed by FT‐IR spectroscopy, and the 2 ‐loaded magnetic nanosilica ( Fe ₃ O ₄ @SiO ₂ /2 ) was characterized by powder X‐ray diffraction, vibrating sample magnetometry, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy and elemental mapping. The Fe ₃ O ₄ @SiO ₂ /2 was found highly efficient, retrievable, eco‐friendly and green catalyst for obtaining β‐amino alcohols in excellent yields in an aqueous medium. Overall, present work is the first report on synthetic, structural and catalytic aspects of dichiral cluster of copper(II)atrane possessing unsymmetrical tricyclic arms.     

高分辨率中红外温度自适应夜视成像系统

针对现代最先进的像元尺寸为15 m、像元数640480的中红外焦平面大面阵探测器,设计了一种全球面轻小型高分辨率温度自适应夜视成像系统,系统工作波段为3~5 m,全视场角为8.58,相对孔径为1/2,焦距为80 mm,四片式结构,使用锗、硒化锌和硅三种材料,系统采用全球面结构,避免了以往该种系统中使用衍射面或非球面,大大降低了加工检测难度且成本低。设计结果表明,该高分辨率温度自适应夜视成像系统具有结构简单、体积小、分辨率高、成像质量高等特点,满足设计要求,可用于机载光电探测和跟踪系统。     

On the cohomology of orbit space of free ℤ<Subscript><Emphasis Type="Italic">p</Emphasis></Subscript>-actions on lens spaces

Let G = ℤ _p , p an odd prime, act freely on a finite-dimensional CW-complex X with mod p cohomology isomorphic to that of a lens space L ^2m−1(p; q ₁, …, q _m ). In this paper, we determine the mod p cohomology ring of the orbit space X/G, when p ² ∤ m.