连接基团链长度对季铵盐二聚表面活性剂C12-s-C12·2Br在水溶液中胶团化行为的影响

用电导法、稳态荧光法和粘度法研究了二聚表面活性剂C12-s-C12*2Br分子中的连接基团链长度(s=2, 3, 4, 6)对其在水溶液中聚集行为的影响. 实验发现, C12-s-C12*2Br的胶团生成能力远比其单体C12TABr强得多, 前者cmc值较后者降低一个数量级. 胶团聚集数N随表面活性剂浓度c的增大而增大, 其中当s=2时的N值在c=7.7 mmol/L后开始急剧增大. 计算结果表明, 此时胶团形状发生了明显变化, 形成了椭球形的胶团. 粘度测定结果也证实了这一点.     

The structure of 1-formyl-3-phenyl-Δ-pyrazoline in the gas phase (DFT calculations), in solution (NMR) and in the solid state (X-ray crystallography)

The molecular structure of 1-formyl-3-phenyl-Δ²-pyrazoline was determined by X-ray crystallography (triclinic, P-1). The geometry thus obtained was compared with that obtained by DFT calculations. The GIAO method was used to calculate absolute shieldings, which agree conveniently with those measured by ¹³C and ¹⁵N NMR. The title compound appears to be an essentially planar molecule.     

SYNTHETIC STUDIES ON BLOOD COMPATIBLE BIOMATERIALS 13:A NOVEL SEGMENTED POLYURETHANE CONTAINING PHOSPHORYLCHOLINE STRUCTURE:SYNTHESIS,CHARACTERIZATION AND BLOOD COMPATIBILITY EVALUATION

A new phosphorylcholine, (6-hydroxy) hexyl-2-(trimethylammonio) ethyl phosphate (HTEP), was synthesized andcharasterized. Segmented polyurethane (SPU) containing phosphorylcholine structure was synthesized based ondiphenylmethane diisocyanate (MDI), soft segment polytetramethylene glycol (PTMG) and HTEP, with 1,4-butanediol (BD)as a chain extender. The existence of phosphorylcholine structure on the surface of SPU was revealed by attenuated totalreflectance Fourier transform infrard spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and water contactangle measurements. The blood compatibilities of the polymers were evaluated by hemolytic testing and a platelet-richplasma (PRP) adhesion experiment, which was viewed by scanning electron microscopy (SEM) with polyurethane as areference. The novel segmented polyurethane containing phosphorylcholine structure showed improved blood compatibility.     

Three-dimensional aromaticity in deltahedral boranes and carboranes

Methods derived from topology and graph theory indicate that the deltahedral boranes B _n H _n ^2– and the corresponding carboranes C₂B_n–2H _n (6 n 12) may be regarded as three-dimensional delocalized aromatic systems in which surface bonding and core bonding correspond to -bonding and -bonding, respectively, in planar polygonal two-dimensional hydrocarbons CinnH _n ^(n–6)+ (n=5/7). The two extreme types of topologies which may be used to model core bonding in deltahedral boranes and carboranes are the deltahedral (D _n ) topology based on the skeleton of the underlying deltahedron and the complete (K _n ) topology based on the corresponding complete graph. Analyses of the Hoffmann-Lipscomb LCAO extended Hückel computations, the Armstrong—Perkins—Stewart self-consistent molecular orbital computations, and SCF MOab initio GAUSSIAN-82 computations on B₆H₆ ^2– indicate that the approximation of the atomic orbitals by the sum of the molecular orbitals, as is typical in modernab initio computations, leads to significantly weaker apparent core bonding approximated more closely by deltahedral (D _n ) topology than by complete (K _n ) topology.This work was presented at the Workshop The Modern Problems of Heteroorganic Chemistry sponsored by the A. N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences (May 8–13, 1993).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1353–1360, August, 1993.     

Crystallochemistry of some new niobium bromides with (Nb6Br18) units: Structures of CsErNb6Br18 and Cs2EuNb6Br18

Two new series of Nb₆ bromides, CsRENb₆Br₁₈ (RE = all the lanthanides excepted Eu and Yb, + Y) (type H ) and M₂RENb₆Br₁₈ (M = Cs, Rb, Tl; RE = Eu, Yb) (type R ) have been isolated. The crystal structures of CsErNb₆Br₁₈ and Cs₂EuNb₆Br₁₈, isotypic with the corresponding chlorides, have been determined by single crystal X-ray diffraction data. The (Nb₆Br₁₈) intra-unit strength is related to the nature and the charge of the counter cation. A comparison between the corresponding chlorides and bromides series, based on the chemical properties and the size of the halogen is discussed.     

[Ni(en)3]4[HVⅣ12VⅤ6O42(PO4)]复合物的合成及晶体结构

A new complex [Ni(en)₃]₄[HV^Ⅳ₁₂V^Ⅴ₆O₄₂(PO₄)] has been hydrothermally synthesized and characterized by X-Ray diffraction, IR and Elemental analysis. Single crystal X-ray analysis indicates that this compoud crystallizes in cubic system,space group Im 3m with a=17.4081(2)?, V=5275.38(10)?³, R=0.0420, wR=0.1055, Z=2, D_c=1.663g·cm^-3, μ=2.297mm^-1, F(000)=2636. The crystal structure consists of [Ni(en)₃]²⁺ cations and {HV₁₈O₄₂(PO₄)}^8- cluster anion which construct from 18 {VO₅} square pyramids. The VO₅ pyramids joined each other to form a {V₁₈O₄₂} cage hosting a tetrahedral {PO₄}^3- moiety with disordered oxygen atoms. CCDC: 185574.     

Synthesis and Crystal Structure of Two Modifications of Hexaaquamagnesium(II) Hypophosphite

Two modifications of hexaaquamagnesium(II) hypophosphite [Mg(H₂O)₆](H₂PO₂)₂ have been synthesized and structurally characterized. Literature data are available for one of these forms. The geometrical characteristics of hexaaqua cations, hypophosphite anions, and nets of hydrogen bonds between the hypophosphite anions and the coordinated water molecules are analyzed. The packing motif of the structure-forming fragments was found to be the same for the two structures, except that modification of the inner structure of the complex cation leads to different nets of hydrogen-bonded cations and anions.     

荧光素及其衍生物电子结构与光谱性质的理论研究

用ZINDO、从头算和密度泛函理论方法研究荧光素及其衍生物的电子结构和光谱性质.计算结果表明母体双阴离子荧光素分子(1)与单(2)、双(3)取代形成的单阴离子荧光素分子的基态电子结构不同,而且1与2和3的基态和激发态的电子转移方向相反.体系1~3的最大吸收波长依次发生红移,与实验结果相符合.     

Synthesis and Structure of Environmentally Relevant Perfluorinated Sulfonamides

Alkylated perfluorooctanesulfonamides are compounds of environmental concern. To make these compounds available for environmental and toxicological studies, a series of N-alkylated perfluorooctanesulfonamides and structurally related compounds were synthesized by reaction of the corresponding perfluoroalkanesulfonyl fluoride with a suitable primary or secondary amine. Perfluoroalkanesulfonamidoethanols were obtained from the N-alkyl perfluoroalkanesulfonamides either by direct alkylation with bromoethanol or alkylation with acetic acid 2-bromo-ethyl ester followed by hydrolysis of the acetate. N-Alkyl perfluorooctanesulfonamidoacetates were synthesized in an analogous way by alkylation of N-alkyl perfluoroalkanesulfonamides with a bromo acetic acid ester, followed by basic ester hydrolysis. Alternatively, N-alkyl perfluoroalkanesulfonamides can be alkylated with an appropriate alcohol using the Mitsunobu reaction. Perfluorooctanesulfonamide was synthesized from the perfluorooctanesulfonyl fluoride via the azide by reduction with Zn/HCl. All perfluorooctanesulfonamides contained linear as well as branched C₈F₁₇ isomers, typically in a 10:1 to 30:1 ratio. The crystal structures of N-ethyl and N,N-diethyl perfluorooctanesulfonamide show that the S-N bond has considerable double bond character. This double bond character results in a significant rotational barrier around the S-N bond (ΔG^≠ = 62-71 kJ mol⁻¹) and a preferred solid state and solution conformation in which the N-alkyl groups are oriented opposite to the perfluorooctyl group to minimize steric crowding around the S-N bond.