含有酯基及酰胺基柔链的苯并菲盘状液晶的合成、分子间氢键对柱状介晶性的影响

合成了三个系列, 共二十四个有两种不同软链的对称和非对称苯并菲盘状液晶化合物, C₁₈H₆(OR)₃- (OCH₂COOEt)₃, C₁₈H₆(OR)₃(OCH₂COOBu)₃, C₁₈H₆(OR)₃(OCH₂CONHBu)₃, 其中R＝C₅H₁₁, C₆H₁₃, C₇H₁₅, C₈H₁₇. 化合物通过柱层析纯化, 结构通过¹H NMR, IR, 元素分析等确证. 化合物热稳定性通过TGA测定, 并显示出较高的热稳定性. 通过偏光显微镜和差视扫描量热法对这些化合物的热致液晶性进行了研究. 结果显示: 对于苯并菲液晶化合物C₁₈H₆(OR)₃(OCH₂COOEt)₃, 非对称性化合物较之对称异构体化合物有更低的熔点和更高的清亮点, 因而非对称性化合物有更宽的介晶温度范围. 对于分子中含有酰胺基的苯并菲液晶化合物C₁₈H₆(OR)₃(OCH₂CONHBu)₃, 对称化合物有比非对称异构体更高的清亮点和更有序的六方柱状介晶相, 且其与具有同样软链长度的分子中不含酰胺基的化合物系列C₁₈H₆(OR)₃(OCH₂COOBu)₃相比较, 由于柱内分子间氢键的形成, 不仅有更高的熔点和清亮点, 而且有更丰富的柱状介晶相.     

γ-苄基膦酸-磷酸锆的合成、表征及插层性能研究

于220℃水热晶化下制备了高结晶度的γ-ZrP,合成了3种γ-苄基膦酸-磷酸锆层状化合物Zr(PO₄).(H₂PO₄)_0.15(C₆H₅CH₂PO₃H)_0.85·0.4H₂O(1,d=1.86nm),Zr(PO₄)(H₂PO₄)_0.30(C₆H₅CH₂PO₃H)_0.70·0.6H₂O(2,d=1.78nm)和Zr(PO₄)(H₂PO₄)_0.50(C₆H₅CH₂PO₃H)_0.50·0.7H₂O(3,d=1.66nm).用X射线粉末衍射和³¹P固态核磁共振等手段表征其结构,并研究了其与α-苯乙胺的插层性能.     

有机磷杀虫剂的研究——Ⅶ.某些苯基对位取代硫代膦酸酯的合成

1.制备一些新型的硫代膦酰氯,其中R'为C₆H₅,R"为C₂H₅O,C₂H₅,(CH₃)₂N,(C₂H₅)₂N,C₂H₅S等。     

中国乌头之研究——Ⅵ.雪上一枝蒿的生物碱(2)

从云南省昭通县产的雪上一枝蒿中共分得生物碱五种,其中三种为已知物,即烏头碱、次岛头碱和一枝蒿乙素,另二种为新生物碱,暂名为一枝蒿戊素和己素。一枝蒿戊素的分子式为C₂₄H₃₉O₆N,其示性式为C₁₉H₂₂(OH)₃(OCH₃)3-(N·C₂H₅);一枝蒿己素的分子式为C₂₄H₃₉O₇N,其示性式为C₁₉H₂₁(OH)₄(OCH₃)₃(N·C₂H₅);另从云南省东川县出产的雪上一枝蒿中,尚分得一新生物碱,暂称为一枝蒿庚素,分子式为C₂₁H₃₁O₃N,其示性式为C₁₉H₂₄(:O)(OH)₂(N·C₂H₅)。     

NMR研究溶液中正十四烷基硫酸钠/正十四烷基聚氧乙烯醚(3)表面活性剂之间的相互作用

采用¹HNMR弛豫、自扩散系数和二维相敏(2DNOESY)实验研究了正十四烷基硫酸钠[n-CH₃(CH₂)₁₃OSO₃Na(STS)]和正十四烷基聚氧乙烯醚(3)[n-CH₃(CH₂)₁₃O(C₂H₄O)₃H(C₁₄E₃)]在溶液中的自聚集以及二者混合后的相互作用.结果表明,STS与C₁₄E₃混合后存在相互作用,并形成混合胶束;弛豫实验表明,混合胶束中STS疏水链质子运动更加受阻,C₁₄E₃的α-(4″)和β-CH₂(3″)处链堆积紧密.C₁₄E₃的亲水端(CH₂CH₂0)₃链卷曲紧贴在疏水壳表面外链堆积较紧密处.自扩散系数测量表明,混合胶束比单一阴离子表面活性剂形成的胶束大.单一非离子型胶束和混合胶束的亲水端(CH₂CH₂0)₃(5″)链构成相应较软和松散的外壳.单一C₁₄E₃在极性溶剂氯仿溶液中,质子运动比在水中自由度大,但2DNOESY谱中出现了少量分子间的交叉峰,也可能形成了一些小的聚集体.     

新型金属-双二硫杂戊烯(M-BDT)配合物的合成、表征及X射线的指标化

合成了4个新型NiBDT配位化合物,BDT为具有9个S原子的杂戊烯.元素分析、IR谱、UV谱确定这4个新配合物的化学式分别为[(CH₃)₄N]₂[Ni(C₅S₉)₂](1),[(C₂H₅)₄N]₂·[Ni(C₅S₉)₂](2),[(C₄H₉)₄N]₂[Ni(C₅S₉)₂](3),[(C₆H₅)(CH₃)₃N]₂[Ni(C₅S₉)₂](4).采用Ito法对配合物1的X射线粉末图进行了指标化,确定该晶体属单斜晶系,简单晶格,晶胞参数:a=0.680nm,b=0.714nm,c=2.302nm,γ=111.4°,Z=2.     

Ru-Fe异金属化合物及其在Au表面上SAM的电化学研究

为使不对称Ru-Fe化合物能在表面上自组装形成单分子膜,对trans-RuCl(dppm)₂(C≡CFc)[Fc=C₅H₄FeC₅H₅,dppm=(C₆H₅)₂PCH₂P(C₆H₅)₂](1)进行修饰,得到Ru(dppm)₂(C≡CFc)(C≡CPhOCH₃)(2),[Ru(dppm)₂(C≡CFc)(N≡CCH₂CH₂NH₂)][PF₆](3)和[Ru(dppm)₂(C≡CFc)(N≡CCH₂CH₂NHC(O)·(CH₂)₁₀SH)][PF₆](4),并详细研究了该系列化合物的电化学性质.循环伏安结果显示出Ru周围配体得失电子能力的差别,直接影响了Ru中心的氧化-还原性,但这种影响并没有通过共轭的炔键传递到二茂铁中的Fe中心.化合物4可以在Au表面上自组装形成稳定、有序的单分子膜.还利用循环伏安法研究了单分子膜的形成过程及其表面覆盖率.     

有玻璃态和液晶态的胆甾烯基苯并菲的合成及介晶性

将盘状液晶基元苯并菲与手性向列型液晶基元胆甾烯基结合的化合物, 可望出现全新的性质. 合成了含有胆甾烯基的苯并菲化合物C₁₈H₆(OC₅H₁₁)₅(OC₅H₁₀COOCh) (2), 2,7-C₁₈H₆(OC₅H₁₁)₄(OC₅H₁₀COOCh)₂ (4), C₁₈H₆(OR)₃(OC_nH_{2nCOO- Ch)3 (R＝C5H11, C7H15, C9H19, C11H23, n＝1, 5, 10) (6a～6f), C18H6(OC5H10COOCh)6 (Ch: cholesteryl) (8). 偏光显微镜和差示扫描量热法对这些化合物的热致介晶性研究结果显示, 化合物 4, 6a～6e具有手性盘状向列相和玻璃态, 8呈现近晶B相(SB)和玻璃态. 随间隔基长度n和烷基链R碳原子数的增加, 化合物玻璃化温度和清亮点呈下降趋势. 随着胆甾烯基数目减少, 化合物的玻璃化温度和清亮点降低.}     

有机锡9-芴酮-4-甲酸酯的合成、结构及抗癌活性

合成了3个有机锡9-芴酮-4-甲酸酯:三苯基锡9-芴酮-4-甲酸酯[(C₆H₅)₃Sn(C₁₄H₇O₃)](1)、三环己基锡9-芴酮-4-甲酸酯[(C₆H₁₁)₃Sn(C₁₄H₇O₃)](2)和三(2-甲基-2-苯基丙基)锡9-芴酮-4-甲酸酯[(C₆H₅C(CH₃)₂CH₂)₃Sn(C₁₄H₇O₃)](3)。通过元素分析、红外光谱、核磁共振谱(¹H、¹³C和¹¹⁹Sn)、热重分析进行了表征;用单晶X射线衍射方法测定了化合物的晶体结构,并对其进行了量子化学计算和体外抗...     

氢键稳定的苯并菲盘状液晶的合成及介晶性

盘状液晶分子能自组装成高度有序的六方柱状介晶相. 其各向异性的载流子高速迁移率使其成为较理想的有机光电子材料. 采用分子间氢键锚定柱状相, 获得介晶相温度范围宽、有序度高的苯并菲盘状液晶是本研究的目的. 本文通过分子设计, 合成了3个系列, 共18个有两种不同软链的苯并菲盘状液晶化合物C₁₈H₆(OR)₅(OCH₂COOEt), C₁₈H₆(OR)₅(OCH₂COOBu)和C₁₈H₆(OR)₅(OCH₂CONHBu), 其中R＝C_nH_2n＋1, n＝4～9. 化合物的纯度和结构通过¹H NMR和元素分析确证. 化合物热稳定性通过热重分析(TGA)测定, 并显示出较高的热稳定性. 通过偏光显微镜(POM)和差示扫描量热法(DSC)对这些化合物的热致液晶性进行了研究. 结果显示对于分子中含有酰胺基的苯并菲液晶化合物C₁₈H₆(OR)₅(OCH₂CONHBu), 与具有同样软链长度的分子中不含酰胺键的化合物系列C₁₈H₆(OR)₅(OCH₂COOBu)相比较, 前者由于柱内分子间氢键的形成, 具有更高的熔点和清亮点.     

Interchain doubly-bridged α-helical peptides for the development of protein binders

This work reported the design and synthesis of interchain doubly-bridged α-helical peptides, involving mutual stabilization of two α -helical peptides crosslinked by two interchain bisthioether crosslinkers.     

羰基化合物在Si(100)表面[2+2]环加成和α-H裂解反应的选择性

最近研究表明: 丙酮能与半导体Si(100)表面发生[2+2]环加成和α-H 裂解反应形成相应的Si―C键或Si―O键, 在半导体材料的合成方面具有重要意义. 为进一步弄清不同羰基化合物在Si(100)表面的反应机理,本文应用密度泛函理论方法在B3LYP/6-311++G(d,p)//6-31G(d)水平上较为系统地研究了一系列羰基化合物CH₃COR (R=CH₃, H, C₂H₅, C₆H₅)与Si(100)表面的反应. 研究结果表明: 不论是[2+2]环加成反应还是α-H 裂解反应都对应较低的反应势垒(小于25 kJ·mol^-1); 环加成反应的势垒比α-H 裂解反应的势垒略高; 羰基上的取代基对反应势垒的影响较少; α-H裂解反应产物为动力学和热力学控制产物; 对丁酮来说, 1-位和3-位H原子的裂解反应都比较容易, 势垒相差很小. 这些结果表明羰基化合物与Si(100)表面的反应将得到多种产物.     

Self-assembly of peptide-amphiphile nanofibers: the roles of hydrogen bonding and amphiphilic packing

The role of hydrogen bonding and amphiphilic packing in the self-assembly of peptide-amphiphiles (PAs) was investigated using a series of 26 PA derivatives, including 19 N-methylated variants and 7 alanine mutants. These were studied by circular dichroism spectroscopy, a variety of Fourier transform infrared spectroscopies, rheology, and vitreous ice cryo-transmission electron microscopy. From these studies, we have been able to determine which amino acids are critical for the self-assembly of PAs into nanofibers, why the nanofiber is favored over other possible nanostructures, the orientation of hydrogen bonding with respect to the nanofiber axis, and the constraints placed upon the portion of the peptide most intimately associated with the biological environment. Furthermore, by selectively eliminating key hydrogen bonds, we are able to completely change the nanostructure resulting from self-assembly in addition to modifying the macroscopic mechanical properties associated with the assembled gel. This study helps to clarify the mechanism of self-assembly for peptide amphiphiles and will thereby help in the design of future generations of PAs.     

Characterization of proanthocyanidins in grape seeds using electrospray mass spectrometry

Two proanthocyanidin (PA) fractions, one (Sdp3) with the mean degree of polymerization (mDP) of 3 and the other (Sdp9) with mDP of 9, were obtained from a Vitis vinifera cv. Shiraz grape seed extract. The PA fractions were directly analyzed by electrospray ionization mass spectrometry (ES-MS) and negative ion mass spectra were recorded. The mass spectrum of Sdp3 exhibited only singly charged ions corresponding to the molecular mass of PA with a degree of polymerization (DP) up to 9 (nonamers). In contrast, Sdp9 yielded rather complex mass spectra featuring ions with single [M - H](-), double [M - 2H](2-) and triple [M - 3H](3-) charge representing the molecular masses of PAs up to a DP of 28. In addition, the degree of galloylation per procyanidin (DG) was observed to be up to 5 (pentagallates) in Sdp3 and 8 (octagallates) in the Sdp9. This is the first evidence obtained by mass spectrometry for the distribution of grape seed PAs with such a high degree of polymerization and a broad diversity of galloylation. ES-MS data together with the complementary information provided by acid hydrolysis provides a detailed picture of the composition of grape seed PAs.     

醇/盐双水相体系中α-环己基扁桃酸手性分子识别

以含羟丙基-β-环糊精（HP-β-CD）手性识别剂的醇/盐双水相体系作为一种新型的手性识别萃取体系,研究了α-环己基扁桃酸(CHMA)对映体在其中的手性识别行为.详细考察了HP-β-CD浓度、CHMA浓度、乙醇和硫酸铵质量分数、体系温度和pH值等因素对CHMA对映体分配比（D）和分离因子(α)的影响.结果显示,含有手性识别剂HP-β-CD的乙醇∕硫酸铵双水相体系对CHMA对映体具有很强的手性识别能力;体系中HP-β-CD浓度、乙醇质量分数、温度和pH值等因素对对映体的分离度影响较大;在体系温度为40 ℃,pH值为2,乙醇质量分数为30%,硫酸铵质量分数为15%,HP-β-CD的浓度为50 g.L-1,CHMA浓度为0.5 mmol.L-1时,手性识别分离效果最佳,分离因子（α）达到了1.86.     

Self-assembly combining two bioactive peptide-amphiphile molecules into nanofibers by electrostatic attraction

We describe a new approach to peptide-amphiphile (PA) nanofiber preparation that allows PAs with different bioactive amino acid sequences to be combined into a single fiber. Oppositely charged PAs are synthesized separately and then mixed to produce gels of nanofiber networks at physiological pH. Transmission electron microscopy reveals the formation of fibers approximately 7 nm in diameter and several micrometers long in these dimeric systems. On the basis of NMR and microscopy, we suggest that these nanofibers are cylindrical micelles of mixed composition, formed due to electrostatic attraction between the oppositely charged PAs. This strategy for self-assembly may be useful in cell therapies that can be implemented without invasive surgery or in in vitro tissue engineering.     

萃取Fe3+和氨水-乙醇反萃沉淀法制备α-Fe2O3

以磷酸二异辛基酯(P204)为萃取剂,CCl4为溶剂,从Fe(NO3)2水溶液中萃取铁离子,以氨的乙醇溶液反萃含铁的有机相,通过优化控制相间传质过程,获得了Fe(OH)3前驱体,经煅烧后得α-Fe2O3粉体,采用TEM、FTIR、XRD等测试技术对α-Fe2O3进行表征。 研究表明,在油水相比为1∶1,水相c(Fe3+)=0.10 mol/L(pH=3.0)、油相P204为V(P204)∶V(CCl4)=1∶3、平衡时间为20 min,Fe3+萃取率达98.44%;反萃取溶液V(氨水)∶V(乙醇)=1∶7、陈化温度约10.0 ℃,制备纳米α-Fe2O3的煅烧温度为600 ℃较宜。     

Static polarizability and second hyperpolarizability of closed- and open-shell pi-conjugated polymers

The static longitudinal linear polarizability (alpha) and second order hyperpolarizability (gamma) for neutral and charged, closed- and open-shell trans-polyacetylene (PA) chains C(2n)H(2n+2), C(2n-1)H(2n+1), C(2n-1)H(2n+1) (+), C(2n)H(2n+2) (+), and C(2n)H(2n+2) (2+) are systematically investigated and compared. The polarizabilities are calculated within the Pariser-Parr-Pople model, and the electron correlation effect is included through density matrix renormalization group. It turns out that for both alpha, and gamma, two neutral PA chains C(2n)H(2n+2) and C(2n-1)H(2n+1) give similar values, while both singly charged and doubly charged systems present significantly larger magnitude of alpha and gamma values than the two neutral chains. The two singly charged PA chains C(2n-1)H(2n+1) (+) and C(2n)H(2n+2) (+) give more apparent nonlinear optical responses than doubly charged case C(2n)H(2n+2) (2+) and both present negative second order hyperpolarizabilities for short to medium sized oligomers. The sign inversion of gamma values in singly charged PA molecules is anticipated to take place at the much longer length than ever observed due to the significant effects of electron correlation and geometry.     

聚L-丙氨酸-聚乙二醇嵌段共聚物的胶束化行为研究

以氨基聚乙二醇单甲醚(MPEG-NH₂)为大分子引发剂, 采用开环聚合方法合成了聚L-丙氨酸-聚乙二醇嵌段共聚物(PAME), 并对其结构进行了表征; 用圆二色谱(CD)研究了嵌段共聚物在水溶液中的二级结构, 用芘荧光探针技术研究了共聚物胶束的形成及其临界胶束浓度(CMC), 利用动态光散射(DLS)和透射电镜(TEM)研究了胶束的粒径分布和形态. 结果表明, 在水溶液中共聚物链以α-螺旋构象形式存在, 在一定条件下嵌段共聚物能够形成球形的稳定胶束, PAME-1形成胶束的CMC为1.99×10^-5 mol/L, CMC值受共聚物中聚L-丙氨酸(PLA)链段含量的影响.     

Self assembled 12-tungstophosphoric acid-silica mesoporous nanocomposites as proton exchange membranes for direct alcohol fuel cells

A highly ordered inorganic electrolyte based on 12-tungstophosphoric acid (H(3)PW(12)O(40), abbreviated as HPW or PWA)-silica mesoporous nanocomposite was synthesized through a facile one-step self-assembly between the positively charged silica precursor and negatively charged PW(12)O(40)(3-) species. The self-assembled HPW-silica nanocomposites were characterized by small-angle XRD, TEM, nitrogen adsorption-desorption isotherms, ion exchange capacity, proton conductivity and solid-state (31)P NMR. The results show that highly ordered and uniform nanoarrays with long-range order are formed when the HPW content in the nanocomposites is equal to or lower than 25 wt%. The mesoporous structures/textures were clearly presented, with nanochannels of 3.2-3.5 nm in diameter. The (31)P NMR results indicates that there are (≡SiOH(2)(+))(H(2)PW(12)O(40)(-)) species in the HPW-silica nanocomposites. A HPW-silica (25/75 w/o) nanocomposite gave an activation energy of 13.0 kJ mol(-1) and proton conductivity of 0.076 S cm(-1) at 100 °C and 100 RH%, and an activation energy of 26.1 kJ mol(-1) and proton conductivity of 0.05 S cm(-1) at 200 °C with no external humidification. A fuel cell based on a 165 μm thick HPW-silica nanocomposite membrane achieved a maximum power output of 128.5 and 112.0 mW cm(-2) for methanol and ethanol fuels, respectively, at 200 °C. The high proton conductivity and good performance demonstrate the excellent water retention capability and great potential of the highly ordered HPW-silica mesoporous nanocomposites as high-temperature proton exchange membranes for direct alcohol fuel cells (DAFCs).