七元瓜环与N,N’-二烷基-1,3-(4,4’-二吡啶基)丙烷衍生物的相互作用

以1,3-(4,4’-二吡啶基)丙烷为母体, 合成了N,N’-二乙基、二丁基、二己基以及二辛基1,3-(4,4’-二吡啶基)丙烷衍生物. 利用1H NMR技术和紫外吸收光谱法, 考察了Q[7]与上述链状吡啶衍生物的相互作用. 实验结果表明, Q[7]与客体PC0, PC2作用, 瓜环包结客体的二吡啶基丙烷部分形成1∶1的包结配合物; 对于取代烷基碳链数大于4的N,N’-二烷基-1,3-(4,4’-二吡啶基)丙烷衍生物, 随着主体与客体摩尔比值的增加, 体系中主-客体相互作用的主导模式是Q[7]逐渐包结了客体二吡啶基丙烷部分, 进而形成Q[7]包结客体两端取代烷基, 甚至形成一个客体分子上“挂满”3个主体瓜环的包结物.     

七元瓜环与N,N′-二烷基-1,3-(4,4′-二吡啶基)丙烷衍生物的相互作用

以1,3-(4,4′-二吡啶基)丙烷为母体,合成了N,N′-二乙基\,二丁基\,二己基以及二辛基1,3-(4,4′-二吡啶基)丙烷衍生物.利用 1H NMR技术和紫外吸收光谱法,考察了Q[7]与上述链状吡啶衍生物的相互作用.实验结果表明,Q[7]与客体PC0,PC2作用,瓜环包结客体的二吡啶基丙烷部分形成1∶1的包结配合物;对于取代烷基碳链数大于4的N,N′-二烷基-1,3-(4,4′-二吡啶基)丙烷衍生物,随着主体与客体摩尔比值的增加,体系中主-客体相互作用的主导模式是Q[7]逐渐包结了客体二吡啶基丙烷部分,进而形成Q[7]包结客体两端取代烷基,甚至形成一个客体分子上"挂满"3个主体瓜环的包结物.     

荧光光谱法研究葫芦[7]脲与6-巯嘌呤和腺嘌呤的包结作用

采用荧光光谱法分别研究了葫芦[7]脲(CB[7])对6-巯嘌呤(6-MP)和腺嘌呤(ADP)的包结作用。实验考察了时间、pH值以及温度对荧光强度和包结作用的影响,利用Benesi-Hildebrand方程分别计算出6-MP和ADP与CB[7]的包结常数。结果表明:酸度对体系的包结有明显的影响。在pH值为8.0和2.0左右时,6-MP和ADP分别具有稳定和最佳激发和发射波长,随着CB[7]浓度的增大,体系的荧光强度都有明显增强,包结作用迅速(小于5 min)。实验得出CB[7]与6-MP和ADP的包结比均为1∶1,在298 K时的包结常数分别为3.6797×102L·mol-1和2.2033×102L·mol-1。通过热力学参数的变化,探讨了维系包结物稳定性的主要作用力。CB[7]是葫芦脲家族中水溶性最强的主体分子,作为一种安全低毒的药物载体极具潜力。     

瓜环[8]与盐酸异丙嗪药物的相互作用研究

本文通过核磁共振(1H NMR)技术、电喷雾质谱(ESI-MS)、红外(IR)光谱以及紫外-可见(UV-Vis)吸收光谱等方法研究了瓜环[8](CB[8])与盐酸异丙嗪(YBQ)形成的超分子体系。实验结果表明,YBQ与CB[8]形成了稳定的1∶1包合物,整个YBQ分子都被包结在CB[8]空腔内。通过UV-Vis法得到CB[8]与YBQ的包结稳定常数约为5 276L/mol,其包结稳定常数处于102~103 L/mol之间,表明CB[8]对YBQ具有潜在的药物缓释作用。     

六元瓜环与含双苯并咪唑功能基烷烃的自组装模式及晶体结构

以含有双苯并咪唑功能基的烷烃化合物二氯化-1,4-二(2,2’-苯并咪唑基)丁烷(SBB)为客体,普通六元瓜环(Q[6])为主体,利用1H NMR技术、荧光发射光谱和X-单晶衍射实验等考察了主客体的自组装模式.1 H NMR技术结果显示,当主客体的比例为1:1时,在水溶液中,1个Q[6]包结1个客体分子的一端苯并咪唑基团;在结晶固态条件下,X-单晶衍射实验测试结果是Q[6]包结客体分子的烷基链.荧光发射光谱表明,当主客体比例为2:1时,2个Q[6]分别包结1个客体分子的两端苯并咪唑基团形成哑铃型的实体配合物。     

苯乙烯基-4-吡啶菁-β-环糊精的合成及光稳定性研究

近年来,人们将菁染料应用光存储材料、非线性光学材料和生物荧光标记[1-4]等领域.然而,菁染料光稳定性较差的缺陷影响了其广泛应用.当前,环糊精的研究已经成为化学领域的热点之一,许多化合物与环糊精形成包合物或被环糊精修饰后对热、光、氧化剂更加稳定[5].本文首次合成了一种新型的苯乙烯基-4-吡啶菁-β-环糊精,这种新型的苯乙烯基吡啶菁可以利用分子内或分子间的包结作用使其稳定性得到提高,克服了菁染料稳定性差的缺点.     

七、八元瓜环与3-氨基香豆素的主客体相互作用

利用紫外-可见吸收光谱法、荧光光谱法、等温量热滴定法和核磁共振波谱法考察了七、八元瓜环(Q[7]、Q[8])与3-氨基香豆素(3-AC)之间的主客体相互作用。结果表明Q[7]与3-AC在pH=1.03的条件下形成包结比为1∶1的主客体配合物,紫外-可见吸收光谱和荧光吸收光谱测得的主客体包结稳定常数分别为3.789×10~4 L·mol~(-1)、4.136×10~4 L·mol~(-1);Q[8]与3-AC在pH=1.03～6.97条件下均形成包结比为1∶1的主客体配合物,在中性条件下,紫外-可见吸收光谱和荧光吸收光谱测得的主客体包结稳定常数分别为2.551×10~5 L·mol~(-1)、2.455×10~5 L·mol~(-1)。其包结模式为3-氨基香豆素分子完全进入Q[7]或Q[8]分子空腔,主客体相互作用过程主要由焓和熵驱动。相溶解度法研究表明Q[7]、Q[8]的介入使3-AC在水中的溶解度分别增加了1.26倍和2.04倍。     

八元瓜环与1,7-二(2-苯并咪唑)-庚烷的超分子自组装

以氯化1,7-二（2-苯并咪唑）-庚烷（SBHt）为客体,八元瓜环（Q[8]）为主体,利用¹H NMR技术、动态光散射实验、荧光发射光谱、紫外吸收光谱详细探索了其在溶液中的相互作用、超分子自组装过程及作用模式. 首先考察了八元瓜环对客体pKa的影响,确定了研究主客体相互作用的条件,并详细探索了主客体的超分子自组装过程及作用模式. 主体Q[8]与客体SBHt相互作用的¹H NMR谱图表明,主客体相互作用自组装形成1：1超分子聚合物. 这一推断得到动态光散射实验、紫外吸收光谱、荧光发射光谱测定结果的证实,并通过紫外吸收光谱、荧光发射光谱确定其表观稳定常数分别为2.79×10⁵ L/mol及2.48×10⁵ L/mol. 而晶体结构测定表明主体Q[8]与客体SBHt自组装形成1：2的简单包结配合物. 导致Q[8]与SBHt在溶液中和固体状态下形成不同自组装结构可能源于瓜环的外壁作用与包结作用竞争所致.     

葫芦[7]脲的合成及其与甲基橙的超分子行为研究——综合性研究型实验设计

以尿素为原料合成甘脲,再与甲醛反应合成葫芦脲,然后通过红外、紫外、核磁对其进行表征。详细研究了葫芦[7]脲与甲基橙的超分子包结行为。本实验可使学生接触到超分子化学,有利于学生了解有关葫芦脲的合成方法和包结性质,提高综合分析问题和解决问题的能力。     

反式七元瓜环与N,N'-二苄基-4,4'-联吡啶氯化物的络合行为研究

利用核磁共振技术、 紫外-可见吸收光谱、 荧光发射光谱、 等温量热滴定及基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)等方法研究了N,N'-二苄基-4,4'-联吡啶氯化物(G1, 客体分子)与反式七元瓜环(iQ[7], 主体分子)的相互作用及形成的主客体包结配合物的结构特征. 结果表明, 客体分子两端的苄基部分分别进入iQ[7]的空腔, 而4,4'-联吡啶则一部分被iQ[7]的空腔所包结, 另一部分处于iQ[7]的端口, 形成包结比为2:1的哑铃型主客体超分子组装体.     

Conformation perturbation of p-sulfonatocalix[5]arene via complexation of 1,4-diazabicyclo[2.2.2]octane

A novel conformation of p-sulfonatocalix[5]arene has been established in the solid state with two calixarenes organised in a 'bis-molecular capsule' shrouding two di-protonated DABCO molecules and two water molecules within.     

Phosphorus-based p-tert-butylcalix[5]arene ligands

New calix[5]arene trivalent phosphorus derivatives have been synthesized which should be excellent ligands with which to study and control the interaction of a ligand atom with a metal. The larger cavity of the calix[5]arene (compared to calix[4]arene) provides a good balance between constraint and flexibility. Treatment of p-tert-butylcalix[5]arene with 2 equiv of either tris(dimethylamino)phosphine or dichlorophenylphosphine inserts two RP moieties into the calix[5]arene framework to give calix[5](PR)2(OH) (1, R = Me2N; 2, R = Ph). Further treatment of 1 with 4 equiv of HCl gives calix[5](PCl)2(OH) (3). Heating a solution of the monophosphorus compound calix[5](PNMe2)(OH)3 (4) releases dimethylamine to yield both monomeric calix[5](P)(OH)2 (6) and dimeric [calix[5](P)(OH)2](2) (7), the latter having a tubelike geometry. X-ray crystallographic studies confirm the structures and show that 1 and 2 have approximate cone conformations while 3 has an approximate 1,2-alternate conformation. The orientations of the phosphorus lone pairs and oxygen atoms in all derivatives provide a framework for both soft and hard ligand interactions within the calix[5]arene.     

An Interesting Approach to Bis-calix[5]arene Analogue from Calix[6]arene

Calix [n] arenas {n = 4, 6 or 8} are easily prepared from formaldehyde and para-substituted phenols via cyclic condensation under alkaline conditions in one step. It is not surprising that the calyx [n] arene (n = 4, 6, 8) chemistry has been developing very rapidly during the latest 20 years1. However, it is not the case for calixarenes with odd benzene rings (for example, n = 5). The yield of p-tert-butylcalix [5] arene synthesized in one-step from p-tert-butylphenol and formaldehyde was a…     

Complexation of 1,4-bis(pyridinium)butanes by negatively charged carboxylatopillar[5]arene

The binding behavior of substituted 1,4-bis(pyridinium)butane derivatives (X-Py(CH(2))(4)Py-X, X = H, 2-methyl, 3-methyl, 4-methyl, 2,6-dimethyl, 4-pyridyl, and 4-COOEthyl) 1(2+)-7(2+), with negatively charged carboxylatopillar[5]arene (CP5A) has been comprehensively investigated by (1)H NMR and 2D ROESY and UV absorption and fluorescence spectroscopy in aqueous phosphate buffer solution (pH 7.2). The results indicated that the position of the substituents attached on pyridinium ring dramatically affects the association constants and binding modes. 3- and 4-Substituted guests (1(2+), 3(2+), 4(2+), 6(2+), 7(2+)) form [2]pseudorotaxane geometries with CP5A host, giving very large association constants (>10(5) M(-1)), while 2,6-dimethyl-substituted 5(2+) forms external complex with relatively small K(a) values [(2.4 ± 0.3) × 10(3) M(-1)] because the 2,6-dimethylpyridinium unit is too bulky to thread the host cavity. Both of the binding geometries mentioned above are observed for 2(2+), having one methyl group in the 2-position of pyridinium. Typically, the association constant of [2]pseudorotaxane 1(2+)?CP5A exceeds 10(6) M(-1) in water, which is significantly higher than those of previously reported analogues in organic solvents. The remarkably improved complexation of bis(pyridinium) guests by the anionic host was due to electrostatic attraction forces and hydrophobic interactions.     

Voltammetric Behavior of 1,4‐Dimethoxypillar[m]arene[n]quinones

The electrochemical properties of a series of 1,4‐dimethoxypillar[m]arene[n]quinones (DMP[m]A[n]Qs) and the interactions between individual quinone units have been investigated on glassy carbon electrode in acetonitrile. All the quinone units showed relative electron uptake behavior except 1,4‐dimethoxypillar[5]quinones (DMP[5]Q). The results have shown that the electrochemical behavior of the DMP[m]A[n]Qs is comparatively different from that of their related linear quinone analogues. The resultant properties were attributed to the close proximity of redox‐active sites as well as the delocalization of electrons on the aromatic rings. Another aspect to be considered responsible for their electronic properties was suggested to be the electrostatic repulsions between adjacent quinone units in these complex structures. Current studies provide a better understanding on the voltammetric behavior of pillararene derivatives with different numbers of quinone units as well as their future scope in certain future electrochemical applications.     

Comparison of pillar[5]arene and calix[4]arene anion receptor ability in aqueous media

Abstract

Recognition ability of both cationic pillar[5]arene and calix[4]arene has been studied in aqueous media. Anion complexation can be evaluated from their ability to complex their counterions as well as an added external organic anion. DOSY NMR experiments and fluorescence quenching show that pillararenes have a larger ability for including their own counterions than calixarenes irrespective of the anion (tetrafluoroborate or chloride or bromide) and the structure of the cationic moiety (trimethylammonium or methylimidazolium). Counterion complexation shows a picture where four to five positive charges of the pillar[5]arene are neutralised, meanwhile only one positive charge of the calixarene is neutralised for a 1 mM solution of the macrocycle. Irrespective of the smaller net positive charge in the pillar[5]arene, its binding ability for organic anions (toluenesulfonate or hydroxybenzoate) is larger than for calix[4]arene allowing a better accommodation of the guest in its cavity. The larger separation between the cationic groups of the receptor and its electron-rich aromatic region improves the anion recognition ability for pillar[5]arene.     

Syntheses of a pillar[4]arene[1]quinone and a difunctionalized pillar[5]arene by partial oxidation

A pillar[4]arene[1]quinone and a difunctionalized pillar[5]arene have been synthesized by partial oxidation.