去叔丁基杯[8]芳烃乙酸钠对紫杉醇包合作用的研究

采用紫外分光光度法和荧光光谱法研究去叔丁基杯[8]芳烃乙酸钠对紫杉醇的包合和释放过程,考察了二者物质的量之比、温度等因素对包合作用的影响.结果显示去叔丁基杯[8]芳烃乙酸钠在一定条件下与紫杉醇可形成稳定的超分子包合物,包合后水溶性明显提高,且随着去叔丁基杯[8]芳烃乙酸钠/紫杉醇物质的量之比的增加,荧光强度明显增强.去叔丁基杯[8]芳烃乙酸钠今后有望成为紫杉醇类抗肿瘤药物的良好载体.     

对叔丁基杯[8]芳烃/12-钨(钼)磷(硅)杂多酸超分子包合物的合成与性质

用自识别自组装法合成了三种新型对叔丁基杯[8]芳烃/12-钨(钼)磷(硅)杂多酸超分子包合物,C88H115～116O8[XM12-040](X=P,Si;M=w,Mo),用元素分析,IR,UV,1H NMR,31P NMR,ESR,XPS,Fluorescence光谱进行了表征.结果表明,对叔丁基杯[8]芳烃主体化合物与12-钨(钼)磷(硅)杂多酸客体分子发生了主-客体包合反应,生成了稳定的发光包合物.     

5,11,17,23-四叔丁基-25,26,27,28-四[3-(甲氧基羰基)苄氧基]杯[4]芳烃包合性能的研究

杯芳烃是继冠醚和环糊精后的第三代主体化合物 .这类主体分子不仅可以识别和络合阳离子 ,而且还具有包合中性有机分子的性能 [1～ 5] .杯 [4]芳烃类包合物的晶体结构测定表明 ,它们可分为分子内和分子间包合两种类型 [3 ,5] ,前者是客体分子被包合在主体分子的空穴内 ,后者是客体分子被包合在主体分子之间 .对叔丁基杯 [4]芳烃的下沿酚氧基与上沿均可进行化学修饰得到不同的杯 [4]芳烃衍生物 .最早报道的对叔丁基杯 [4]芳烃及其衍生物的分子内包合物是与甲苯或乙腈的 1∶ 1包合物 [4 ,5] ,客体分子依靠 CH3 -π的作用被包结在主体分子内[6]…     

乙腈溶液中对叔丁基杯[4]芳烃与一些脂肪胺间的相互作用

用紫外可见光谱法和电导法研究了乙腈溶液中一些脂肪胺与对叔丁基杯[4]芳烃间的相互作用。考察了它们之间的反应机理,测定了它们之间各步反应的平衡常数及表观复合常数等。由紫外可见光谱得到的表观复合常数和同一方法得到的文献值数量级相同但数值相差几倍。电导测定表明在乙腈溶液中脂肪胺与对叔丁基杯[4]芳烃间的反应分两步进行:首先胺从杯芳烃得到一个质子生成胺正离子和杯负离子,然后离子再进一步包合。其总复合常数远小于其表观复合常数。且在对叔丁基杯[4]芳烃的饱和溶解度以下,质子转移所生成的离子是反应的主要产物。结果与文献中结论相反。     

富勒烯的杯芳烃包合物的研究现状与展望

介绍了[60/70]富勒烯与杯[8],[6],[5]芳烃、高氧杂杯[3]芳烃及双杯芳烃形成包合物的研究进展和应用前景。     

水溶液中对磺酸钠杯[8]芳烃醚与芘间的相互作用

用荧光法研究了一个长链水溶性杯芳烃醚-十二烷基对磺酸钠杯[8]芳烃醚与芘在水溶液中的相互作用,以及盐氯化钠和共溶剂甲醇对此作用的影响。结果表明:芘进入了此杯芳烃醚的疏水孔穴形成了包合物;其复合常数和短链对磺酸钠杯芳烃醚的复合常数相近,但其疏水孔穴的非极性明显加大;且在盐及甲醇浓度较小时,它们对上述相互作用及复合常数的影响都不大。     

脲基杯[4]二(9-冠-3)对钠-卤素离子对的识别作用

采用Oniom方法(B3LYP/LANL2DZ∶PM3)对脲基取代的二(9-冠-3)杯[4]芳烃衍生物(H)与离子对Na+X-(X=F-,Cl-,Br-)的包合作用进行了理论研究.在上述体系中存在2种包合方式:一是阴、阳离子在包合物中是分离的,阴离子与主体分子的上沿主要以N—H…X-氢键作用;二是阴、阳离子在包合物中存在明显的离子配对作用,阴离子主要以阳离子的配对作用存在.通过对包合物Na+X-/H的结构参数、自然键轨道(NBO)以及结合能分析可知,第1种包合方式更有利.研究表明脲基取代的二(9-冠-3)杯[4]芳烃衍生物可成为有效的离子对识别受体,研究结果进一步加深了杯芳烃类受体对离子对识别机理的认识,为实验上设计合成新型离子对受体提供了理论依据.     

杯芳烃的研究 II: 四羟基杯[4]芳烃包合性能的研究

本文利用X射线衍射法研究了四羟基杯[4]芳烃与水、氯仿的包合物的晶体结构,它们属六方晶系, 为分子间包合物。通过这些研究发现: 在晶体中, 四羟基杯[4]芳烃是通过六重螺旋轴的作用形成一种管道型的空间来包合客体分子, 这种管道具有对客体分子选择性等特点。     

杯芳烃的研究 II: 四羟基杯[4]芳烃包合性能的研究

本文利用X射线衍射法研究了四羟基杯[4]芳烃与水、氯仿的包合物的晶体结构,它们属六方晶系, 为分子间包合物。通过这些研究发现: 在晶体中, 四羟基杯[4]芳烃是通过六重螺旋轴的作用形成一种管道型的空间来包合客体分子, 这种管道具有对客体分子选择性等特点。     

叔丁基杯[6]芳烃的去叔丁基反应

报道了以对叔丁基杯[6]芳烃为原料,室温时,在三氯化铝催化下选择性脱去叔丁基的工艺.探讨了在合成去叔丁基杯[6]芳烃实验中催化剂用量对反应结果的影响,并对反应机理进行了讨论.结果表明,当n(AlCl3)∶n(p-tert-calix[6]arene)=8~9.5∶1时,分离得到了两种去叔丁基杯[6]芳烃:5-叔丁基-37,38,39,40,41,42-六羟基杯[6]芳烃和37,38,39,40,41,42-六羟基杯[6]芳烃,当n(AlCl3)∶n(p-tert-calix[6]arene)=10.5∶1时,得到37,38,39,40,41,42-六羟基杯[6]芳烃,产率90.8%.     

C_(60)键合硅胶液相色谱固定相的合成及其性能评价

 以γ－（乙二胺基）丙基三乙氧基硅烷为偶联剂合成了Ｃ６０键合硅胶固定相；用元素分析法测定得到该固定相的Ｃ６０键合量为５７．５７μｍｏｌ／ｇ。考察了多环芳烃和杯芳烃在Ｃ６０键合硅胶固定相上的分离，多环芳烃在该固定相上的洗脱顺序与ＯＤＳ固定相相似；杯芳烃的洗脱顺序为杯［８］、杯［４］和杯［６］芳烃。     

(C_(70))_2-对叔丁基杯[8]芳烃化学修饰电极对卤代酸的电催化行为

(C_(70))_2-对叔丁基杯[8]芳烃化学修饰电极在V（乙腈）：V（水）＝2：3混 合溶剂中,发生两步还原／再氧化反应,分别对应于两电子和四电子转移。用扫描 电子显微镜和光电子能谱对修饰电极进行了表征。循环伏安实验表明,(C_(70)) _2-对叔丁基杯[8]芳烃的两步还原过程均匀卤代酸的还原具有电催化作用。     

Supramolecular structures formed by calix[8]arene derivatives

Octamethoxy calix[8]arenes substituted in the para position by amide, urea, and imide functions were synthesized from the octamethyl ether of tert-butylcalix[8]arene by ipso nitration, reduction, and acylation. Scanning force microscopy of spin coated samples on graphite suggests that these derivatives self-organize into tubular nanorods via hydrogen bonds between p-amide functions. A single-crystal X-ray structure reveals a centrosymmetric conformation for the octanitro derivative. [structure: see text]     

Microwave-Assisted and Thermal Synthesis of Calix[4]arene Derivatives

Russian Journal of Organic Chemistry - Some tert-butylcalix[4]arene derivatives were synthesized by thermal and microwave methods. The microwave method was conducted in two ways: (1) all the...     

Stilbene-bridged tert-butylcalix[4]arene as photoswitchable molecular receptors

Using a designed control of conformations of tert-butylcalix[4]arene between cone and pinched cone, a highly selective receptor for small electron-deficient molecules with photoswitching binding ability was attained. [reaction: see text]     

Synergistic effect of ligating and ionic functions, prearranged on a calix[4]arene

The covalent attachment of two CMPO-functions and two anionic Cosan groups to the narrow rim of tert-butylcalix[4]arene leads to a dramatic increase of the extraction efficiency for the cone isomer; Am(3+) is removed from 5 x 10(-8) M solution to more than 99% by a single extraction step with a 3 x 10(-6) M solution of the calixarene.     

Adsorption of n-butanol from dilute aqueous solution with grafted calixarenes

Materials were synthesized for the recovery of n-butanol from dilute aqueous solutions, as may be useful for applications in biofuel-water separations. These materials are composed of hydrophobic, cavity-containing calixarenes covalently bound directly to porous, hydrophilic silica supports through a Si linker atom rather than a flexible organic linker, as is common, at surface coverages of up to ～0.25 calixarenes/nm(2) (～250 μmol calix/g matl). The calixarene ring size, upper rim groups, bridging group (calixarene vs thiacalixarene), and surface density were varied. The materials were characterized by NMR, UV-vis, and TGA. The absolute butanol uptake reached ～0.16 mmol butanol per gram of material at equilibrium concentrations below 0.12 M and increased monotonically with the calixarene surface density. The background adsorption onto the silica surface was small at high calixarene loading. At 298 K, the free energy of adsorption in the calixarene cavities became more favorable by 3 kJ/mol as the surface area of the hydrophobic calixarene upper rim groups increased from H to methyl to tert-butyl, consistent with adsorption driven by van der Waals interactions. A thiacalix[4]arene-SiO(2) material, containing polarizable sulfur bridges and a larger, more conformationally mobile calixarene structure, had slightly stronger adsorption still. All materials except this thiacalixarene exhibited fully reversible adsorption into solution. As a representative material, the adsorption of n-butanol from aqueous solution at a tert-butylcalix[4]arene site was accompanied by a negligible enthalpy change but a small, favorable entropy change of +50 ± 20 J/mol/K, indicating that adsorption is driven by desolvation. Butanol desorbed from tert-butylcalix[4]arene materials at ～150 °C into the gas phase, well within the range of stability of calixarenes (<300 °C), indicating that these materials have promise as regenerable adsorbents.     

Metastable tert-butylcalix[6]arene with unusually large tunable free volume for non-threshold enclathration of volatiles

A metastable material with tunable free volume of molecular size, vapor sorption properties of a porous sorbent and variable thermal stability was prepared from tert-butylcalix[6]arene.     

Formation and Optical Absorption of Clusters of the p-tert-butylcalix[8]arene:C60 Complex

Depending on the initial concentrations of fullerene (C₆₀) and p-tert-butyl calix[8]arene (C[8]A) in toluene, two regimes of their interaction were distinguished. The changes in optical absorption of C₆₀:C[8]A mixed solutions observed over a period of time suggest that the following consecutive processes take place upon interaction between C₆₀ and C[8]A in toluene: (1) molecular inclusion, and (2) growth and sedimentation of the insoluble C₆₀/C[8]A clusters. At increased concentrations of the components, process (2) is suppressed and stable C₆₀/C[8]A colloids can be formed. Spectral features of these colloids in different solvents clearly indicate the difference between self-aggregated C₆₀ and small clusters of the complex. A specific influence of the C[8]A cage on the entrapped C₆₀ molecules is also confirmed by IR spectroscopy of the complex in the solid state.     

Estimation of the Free Energy of the Supramolecular Effect on Host–Guest Complex Formation between Solid tert}-Butylcalix[4]arene and Vapors of Organic Compounds

The free energy of the supramolecular effect was estimated by the difference of the free energy of the solid host-guest complex formation between the vapor guest and the solid tert-butylcalix[4]arene ( 1) and the free energy of the guest solvation in toluene. These thermodynamic parameters were obtained from the vapor sorption isotherms of the guests with various molecular structure by solid 1 and limiting activity coefficients of the guests in toluene determined by headspace gas chromatographic analysis. The supramolecular effect was found to decrease slightly with the increase of the guest molecular size.