Infrared Spectroscopy and Structure of Trigonal Zirconium Orthophosphates with Lanthanides and Actinides

Binary zirconium orthophosphates R_1/3Zr₂(PO₄)₃ and M_1/4Zr₂(PO₄)₃, where R = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu; M = Th, U, have been synthesized and studied by IR spectroscopy [structural family of NaZr₂(PO₄)₃ (NZP)]. Vibrational analysis for the PO₄ tetrahedron and investigation of symmetry relations among trigonal NZP phases showed that ordering of lanthanide atoms in structures of NaZr₂(PO₄)₃ type with space group R c leads to symmetry reduced to P c. The lanthanide atoms occupy the 2b sites. The phosphorus atoms occupy two independent sites: 6f with C ₂ symmetry and 12g with C ₁ symmetry. Factor group analysis admits that the IR spectrum can contain eight v₃ bands and two v₁ bands of the stretching vibrations of the PO₄ ions. The M atoms of actinides occupy statistical positions in the structure, and space group R c is retained.Original Russian Text Copyright © 2004 by V. S. Kurazhkovskaya, D. M. Bykov, and A. I. Orlova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1013–1019, November–December, 2004.     

Influence of Pretreatment Conditions on Methane Aromatization Performance of Mo／HZSM—5 and Mo—Cu／HZSM—5 Catalysts

Mo/HZSM-5 is a good catalyst for methane aromatization, and the reaction performance of Mo/HZSM-5 and Cu modified Mo/HZSM-5 catalysts under various pretreatment conditions has been studied. The results indicate that the catalyst presented a distinguished catalytic activity, benzene selectivity and a high stability when the bed temperature was raised in N2 atmosphere.     

Investigation on the Interaction of Bendazac with β-, Hydroxypropyl-β-, and γ-, yclodextrins

The interactions of Bendazac, a topical non-steroidal anti-inflammatory drug, with-cyclodextrin, hydroxypropyl--cyclodextrin and -cyclodextrinwere investigated to evaluate possibilities to improve the drug's poor water solubilityand eventually to enhance the topical delivery of Bendazac. Phase solubility studiesdemonstrated the ability of the selected cyclodextrins to complex with Bendazac andincrease drug solubility. The amount of solubilized Bendazac increased linearly withthe addition of each cyclodextrin according toA_L type plots. ¹³C-NMR studiesshowed that the Bendazac A-ring was included in the cavity of the three cyclodextrins.The -cyclodextrin was also able to include the B-ring of Bendazac, forminga complex where one drug molecule fitted into two cyclodextrin molecules. Equimolarsolid systems of the drug with each cyclodextrin carrier were prepared using varioustechniques (physical mixing, spray-drying and freeze-drying). The results of differential scanning calorimetry and Fourier transform infrared analysis, performed on the solid systems, demonstrated that freeze-dried and spray-dried products had a high degree of amorphization and agreed with the hypothesis of the existence of drug–cyclodextrin interaction in the solid state. The cyclodextrins tested were able to improve the dissolution of Bendazac. The dissolution profile of the drug was also affected by the physico-chemical properties of each solid system, the freeze-dried products being the most rapidly dissolving forms.     

Fourier transform infrared spectroscopy and the analytical study of works of art for purposes of diagnosis and conservation

This paper is a study of the analytical capacity of Fourier transform infrared spectroscopy (FT-IR) for any type of samples from works of art. The analytical information obtained with this technique on organic and inorganic compounds is extremely useful in the preliminary studies necessary for diagnosis and to decide on the conservation process. This paper reports the analysis and study with FT-IR on samples extracted from the microlayers in several works of art from different periods (16th to 18th century) comprising wall paintings and canvas. The most outstanding of these being the frescoes by A. Palomino from two ceilings in the Santos Juanes church. The analytical procedures for the different components of the works studied such as

1. (a) varnish applied to wood panels and canvas paintings,

2. (b) binding media and pigments used by the artists,

3. (c) inerts, mortars, stuccos and grounds have been optimized. The FT-IR technique offers a quick analysis of microsamples (less than 0.5 mg) and is able to characterise the different molecular groups which provide information on the nature of the different materials of organic and inorganic origin used by the artist and thus permits the diagnosis of pathologies requiring conservation treatment.

Synthesis and properties of functional derivatives ofN′-phosphoryl- andN′-phosphonoyldiazeneN-oxides; molecular structure ofN-(2,2-dimethyl-5-nitro-1,3-dioxan-5-yl)-N′-[methoxy(phenyl)phosphoryl]diazeneN-oxide

Methods for the synthesis of polyfunctionalN-phosphoryl- andN-phosphonoyldiazeneN-oxides containing hydroxyl, acetoxyl, and nitrate groups, and dibromoallyl and dibromopropyl fragments have been developed. The molecular structure ofN-(2,2-dimethyl-5-nitro-1,3-dioxan-5-yl)-N-[methoxy(phenyl)phosphoryl)diazeneN-oxide was established by X-ray structural analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1284–1289, July, 1994.     

河豚鱼脂肪酸的气相色谱—质谱分析

采用ＧＣ／ＭＳ技术对２种河豚鱼（黄鳍、红鳍）脂肪提取物中的脂肪酸进行定性定量分析，共鉴别出２４种脂肪酸。多不饱和脂肪酸尤其是二十二碳六烯酸（ＤＨＡ）的含量很高，在黄猪中相对含量达３２．３２％，在红鳍中达２４．１１％。检出了在其它海产品中较少发现的１５－二十四烯酸（神经酸），是人体生长发育不可缺少的一种脂肪酸。对鱼肉脂肪提取方法及不同极性毛细管柱分离情况进行了讨论。     

Calculation of the proton affinities of polyfluorobenzenes and the activation energies for 1,2-hydrogen shifts in their carbocations

Isolated polyfluorobenzene (PFB) molecules and their protonated forms are investigated by the AM1 method with full geometry optimization. The proton affinities of PFB are estimated for different protonated positions. The proton affinity of PFB averaged over all isomers is shown to decrease monotonically as the number of fluorine atoms in the molecule increases. The relative populations of different isomers of arenonium ions (AI) formed by PFB protonation are determined. From the calculated data, the value of ⁺ for the F atom in theipso-position is estimated as 1.00. The activation energies of the 1,2-hydrogen shifts in AI are calculated. The dependences of the proton affinity and the activation energies of 1,2-hydrogen shifts on the number of halogen atoms are found to have distinct characters for PFB and polychlorobenzenes. The physical reasons for these difference are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1878–1882, November, 1993.     

聚酰亚胺/二氧化硅纳米尺度复合材料的研究

通过正硅酸乙酯（ＴＥＯＳ）在聚酰胺酸（ＰＡＡ）的Ｎ，Ｎ’ 二甲基乙酰胺（ＤＭＡｃ），溶液中进行溶胶 凝胶反应，制备出不同二氧化硅含量的聚酰亚胺／二氧化硅（ＰＩ／ＳｉＯ２）复合薄膜材料．二氧化硅含量低于１０ｗｔ％的样品是透明浅黄色薄膜；二氧化硅含量高于１０ｗｔ％的样品是不透明棕黄色薄膜．利用红外光谱、扫描电镜、热失重分析、动态力学分析、热膨胀系数测试和应力 应变测试等方法研究了此类材料的结构与性能．结果表明，ＰＩ／ＳｉＯ２纳米复合材料具有较聚酰亚胺更高的热稳定性和更高的模量；线膨胀系数显著降低；拉伸强度和断裂伸长随二氧化硅含量而变化，分别在１０ｗｔ％和３０ｗｔ％附近出现最大值     

Hydrolysis rates of alkyl and aryl sulfinamides: evidence of general acid catalysis

Sulfinamides are important in enantioselective synthesis, as rare post-translational modifications of proteins and as isosteres of the amide bond. Little is known about the rates of hydrolysis for aliphatic sulfinamides or the mechanism of hydrolysis. In this Letter, we show that sulfinamides hydrolyse by predominantly a non-specific acid/base catalysis with phosphate buffer but by varying the buffer concentration, it was possible to determine the hydrolysis rates of a range of sulfinamides with water through non-linear least squares regression.     

Aromatic H／D Exchange Reaction Catalyzed by Groups 5 and 6 Metal Chlorides

Groups 5 and 6 metal chlorides such as MoCl5, WCI6, NbCl5 and TaCl5 were found to be simple and very efficientcatalysts for the aromatic H/D exchange reactions. Compared with other metal chlorides such as ZnCl2, SnCl4 and TiCl4, groups 5 and 6 metal chlorides showed better catalytic activity in the H/D exchange reaction of naphthalene with C6D6. Deuteration of anthracene using MoC15 as a catalyst proceeded within 24 h at room temperature. Other aromatic compounds such as toluene, diphenylmethane and 1,1,2-triphenylethane were also deuterated smoothly in C6D6 within 24 h at room temperature.