瓜环与1,ω-亚烷基二吡啶二溴化合物主客体作用实体结构研究

合成并表征了六种不同碳链长度的1,ω-亚烷基二吡啶二溴化合物(客体),利用1HNMR技术、紫外吸收光谱和电化学方法考察了这些客体与六、七、八元瓜环(主体)相互作用,以及形成的主客体包结配合物的结构特征.研究结果表明,六种客体均能与六、七、八元瓜环形成主客体配合物,但作用模式随碳链的长度、瓜环的大小而各不相同.     

八元瓜环与二(2-亚甲基-1,2,3,4-四氢异喹啉)的自组装模式

以用1,2,3,4-四氢喹啉和二溴乙烷合成的二(2-亚甲基-1,2,3,4-四氢异喹啉)的溴化氢酸盐为客体, 八元瓜环为主体, 利用1H NMR技术, 单晶X射线衍射方法以及理论计算等方法, 考察了两者的自组装模式. 1H NMR分析结果表明, 在溶液状态条件下, 不仅每一个八元瓜环分子同时与两个客体分子的芳环部分相互作用, 而且每一个客体分子两端的芳环部分同时与两个八元瓜环分子相互作用, 从而形成一维的自组装超分子链; 而在固体状态下, 每一个八元瓜环也可同时包结两个客体的芳环部分而形成三元的自组装结构, 但八元瓜环包结两个客体形成一独立的三元自组装结构. 利用晶体结构建立模型的计算结果说明, 模拟溶液状态比固体状态条件下的主客体包结更有利于体系能量的降低, 与主客体在溶液中1H NMR实验结果相符.     

六元瓜环与二氯化-1,8-二(2-苯并咪唑基)辛烷的自组装模式

采用¹H NMR、 荧光光谱和紫外吸收光谱法考察了主体六元瓜环与合成客体二氯化-1,8-二(2-苯并咪唑基)辛烷的自组装模式. 结果表明, 六元瓜环能与二氯化-1,8-二(2-苯并咪唑基)辛烷发生相互作用, 瓜环包结客体分子的苯并咪唑基团, 烷基链置于瓜环端口外侧. 自组装模式与主客体的摩尔比密切相关. 当主客体的摩尔比为1:1时, 1个瓜环包结客体分子的一端苯并咪唑基团形成棒槌形的包结配合物; 当主客体的摩尔比为2:1时, 2个瓜环分别包结客体分子的两端苯并咪唑基团形成哑铃型的主客体包结配合物.     

八元瓜环对1,ω-二(2-氨基吡啶)烷烃光致环加成反应的超分子催化性能的研究

合成了三种不同链长的1,ω-二(2-氨基吡啶)烷烃,分别为二溴化1,4-二(2-氨基吡啶)丁烷(C4)、二溴化1,6-二(2-氨基吡啶)己烷(C6)、二溴化1,8-二(2-氨基吡啶)辛烷(C8).考察了八元瓜环(Q[8])与上述三种1,ω-二取代烷烃的主客体相互作用,运用1H NMR及UV-vis证明三种客体与Q[8]的作用模式均不相同.在此基础上,考察了八元瓜环对三种底物光致环加成反应的超分子催化性能.结果表明,由于三种底物与Q[8]的主客体作用模式不同,八元瓜环对它们光二聚反应的超分子催化性能也各有差异.     

瓜环与含羟基功能基二胺包结配合物的晶体结构及相互作用的研究

合成并表征了含羟基功能基的二胺1,3-二(2-氨基苯氧基)-2-丙醇(客体). 利用X射线衍射方法研究了客体与八元瓜环Q[8]所形成包结配合物的晶体结构. 结果表明主客体间形成了1∶2的包结配合物, 两个客体分子分别从瓜环的两个端口进入瓜环内腔, 在腔内两个客体分子中的苯环间存在着π-π相互作用. 利用1H NMR技术及紫外-可见吸收光谱对主客体间的相互作用进行考察, 所得结果与晶体结构吻合.     

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.     

两种七元瓜环与3-(2-萘基)-丙氨酸的包结行为分析

以反式七元瓜环(i Q[7])和七元瓜环(Q[7])作为主体分子,一对氨基酸对映体L-3-(2-萘基)-丙氨酸(L-NA)及D-3-(2-萘基)-丙氨酸(D-NA)为客体分子,利用紫外-可见吸收光谱、荧光光谱、等温滴定量热分析、基质辅助激光解吸电离飞行时间质谱以及核磁共振技术等手段,对比探究了这两种具有不同空腔大小的七元瓜环与这一对氨基酸对映体之间的自组装模式的异同点,实验结果表明:这四组主客体包结物具有相同的作用模式,均为瓜环的空腔包结了客体分子的萘环部分而客体分子的氨基及羧酸部分位于瓜环的端口外侧,主客体均以1∶1的作用比相互配位形成较为稳定的超分子自组装体,同时发现两种七元瓜环对L/D-NA手性对映体的分子选择性略有不同.     

七、八元瓜环与N,N''''-二金刚烷基二铵盐酸盐的相互作用

合成了三种二元金刚烷胺化合物(客体)盐酸盐.利用1H NMR技术和质谱分析方法表征了这些客体,考察了七、八元瓜环(主体)分别与上述客体的盐酸盐的相互作用和结构特征.研究结果表明,七元瓜环与三种二元金刚烷胺化合物(客体)盐酸盐形成2:1的哑铃型包结配合物,八元瓜环与三种二元金刚烷胺化合物(客体)盐酸盐形成1:1的棒锤型包结配合物.     

六元瓜环、对称四甲基六元瓜环与2,2'-(1,8-辛烷)-二异喹啉二溴化物的自组装模式

利用核磁共振波谱、 紫外吸收光谱、 荧光光谱和单晶X射线衍射分析等考察了六元瓜环(Q[6])及对称四甲基六元瓜环(TMeQ[6])与2,2'-(1,8-辛烷)-二异喹啉二溴化物的相互作用. 实验结果表明, 客体分子分别与这2种瓜环自组装形成相似的1∶1包结配合物, 但晶体结构分析结果表明两个体系在主客体分子间作用力诱导下形成了不同的空间堆积模式, 其包结常数分别为K_K8-Q[6]=4.18×10⁷ L/mol, K_K8-TMeQ[6]=6.11×10⁷ L/mol.     

七、八元瓜环与N,N'-二金刚烷基二铵盐酸盐的相互作用

合成了三种二元金刚烷胺化合物(客体)盐酸盐. 利用¹H NMR技术和质谱分析方法表征了这些客体, 考察了七、八元瓜环(主体)分别与上述客体的盐酸盐的相互作用和结构特征. 研究结果表明, 七元瓜环与三种二元金刚烷胺化合物(客体)盐酸盐形成2∶1的哑铃型包结配合物, 八元瓜环与三种二元金刚烷胺化合物(客体)盐酸盐形成1∶1的棒锤型包结配合物.     

Host-guest complexes of cucubit[8]uril with phenanthrolines and some methyl derivatives

Cucurbituril a molecular container (or host) has a rigid hollow interior cavity which is large enough to accommodate, one or more, smaller molecules (or guests). The cavity is accessible through two carbonyl portal openings. Molecules or guests enter the …     

瓜环与4,4'-二氨基二苯甲烷衍生物的相互作用

合成了三种长链多芳环多胺基客体, 它们分别由三种醛基吡啶异构体与4,4'-二氨基二苯甲烷形成的Schiff碱还原而成, 并得到¹H NMR以及质谱分析方法表征证实. 以核磁共振技术、紫外吸收光谱分析方法以及滴定¹H NMR方法为研究手段, 对瓜环(cucurbit[n]urils, n＝6～8)分别与三种4,4'-二[N-(吡啶甲基)氨基]二苯甲烷盐酸盐相互作用进行了考察. 实验结果表明, 六元瓜环与三种4,4'-二[N-(吡啶甲基)氨基]二苯甲烷盐酸盐相互作用均形成物质的量之比为2∶1的哑铃型包结配合物; 八元瓜环与三种N,N'-二(N-(吡啶甲基)二苯甲烷盐酸盐相互作用形成以类轮烷结构为主的包结配合物; 七元瓜环与三种N,N'-二(N-(吡啶甲基)二苯甲烷盐酸盐相互作用存在多种模式的竞争.     

瓜环与哌嗪衍生物主客体配合物的研究(英)

本文采用核磁共振技术研究瓜环与哌嗪衍生物主客体配合物的结构特征。¹H核磁共振谱证实八元瓜环能与一些哌嗪衍生物形成稳定的双客体主客体配合物,六元瓜环与一些哌嗪衍生物形成稳定的1∶1主客体配合物。而五、七元瓜环和哌嗪衍生物则未表现出明显地相互作用。形成的自组装主客体配合物得到质谱的进一步证实。     

A cucurbit[6]uril analogue: host properties monitored by fluorescence spectroscopy

This paper describes the host properties of a new cucurbit[6]uril analogue, studied by fluorescence and 1H NMR spectroscopy. This host has an elongated cavity with oval-shaped portals. It is intrinsically fluorescent, and more importantly, this fluorescence is sensitive to guest encapsulation, allowing for the study of the inclusion of nonfluorescent guests by fluorescence spectroscopy. In the case of benzene as guest, significant enhancement of the cucurbit[6]uril analogue host fluorescence was observed upon addition of benzene; this allowed for the determination of the binding constant for 1:1 host-guest complexation, yielding a value of K = 6900 +/- 1100 M(-1). This complexation was also studied by 1H NMR, yielding a similar value of K = 8980 +/- 500 M(-1). The binding of a much larger guest, the dye Nile Red, was also studied, but in this case using guest fluorescence. Significant suppression of the Nile Red fluorescence was observed upon 1:1 complexation with the cucurbit[6]uril analogue, with an extremely large binding constant of 8.2 +/- 0.5 x 10(6) M(-1), indicating a very strong host-guest interaction and an excellent size and shape match. In both cases, binding was much stronger than in the case of the same guests with cucurbit[6]uril itself, and in the case of Nile Red, binding was also much stronger than with modified beta- or gamma-cyclodextrins. This is partly a result of the partial aromatic nature of the host walls, which allow for pi-pi interactions not possible in cucurbiturils or cyclodextrins. The ability to study its inclusion complexes using either host or guest fluorescence, and the very high binding constants observed, illustrates the versatility and potential usefulness of this new host compound.     

Inclusion of Carboxyl Function Inside of Cucurbiturils and its Use in Molecular Switches

We have prepared organic guest molecules in which two pyridinium rings are connected through an aromatic/aliphatic bridge bearing a carboxyl group. The supramolecular interactions between these guests and macrocyclic hosts cucurbit[7]uril ( CB7 ) and cucurbit[8]uril ( CB8 ) has been studied. We have demonstrated that the binding modes of the complexes depend on the type of central bridge present in the guest molecules and the size of the macrocycle. We have also showed that the binding mode between cucurbiturils and guests with aromatic bridges is pH independent. On the other hand, a guest containing an aliphatic bridge and CB7 formed a pseudorotaxane, which behaved as a pH‐driven molecular switch.     

七、八元瓜环对萘二胺异构体相互作用的考察

利用紫外吸收光谱、荧光光谱以及¹H NMR方法考察了七、八元瓜环(Q[7], Q[8])与1,8-萘二胺(g1), 2,3-萘二胺(g2), 1,5-萘二胺(g3)的相互作用. 实验结果表明: Q[7]与客体g1发生端口作用, 作用比为1∶1; Q[7]与客体g2, g3相互作用也形成1∶1的包结配合物. Q[8]与三种客体相互作用情况各不相同, 除Q[8]与客体g2相互作用形成1∶2的包结配合物; Q[8]与客体g1或g3可发生相互作用, 形成溶解性较差的作用产物, 其表观相互作用的比例为1∶1. 考察溶液酸度对主客体相互作用的影响还表明: 当pH大于某一值之后, 如Q[7]主客体体系, pH大于6.0; Q[8]主客体体系, pH大于12.0, 用光谱方法观察不到瓜环与客体的相互作用. Q[7], Q[8]为主体的上述主客体作用产物分别与金刚烷胺盐酸盐、1,10-癸二胺盐酸盐的竞争反应结果表明, 已作用的萘二胺异构体容易被所选用的竞争客体所取代, 只有g2与Q[8]形成的包结配合物被1,10-癸二胺盐酸盐部分取代.     

Interaction between tetramethylcucurbit[6]uril and some pyridine derivates

Interaction between tetramethylcucurbit[6]uril (TMeQ[6], host) with hydrochloride salts of 2-phenylpridine (G1), 2-benzylpyridine (G2), and 4-benzylpyridine (G3) (guests) have been investigated by using 1H NMR spectroscopy and electronic absorption spectroscopy and theoretical calculations. The 1H NMR spectra analysis established an interaction model in which the host selectively included the phenyl moiety of the HCl salt of the above three guests, and formed inclusion complexes with a host-guest ratio of 1:1. Absorption spectrophotometric analysis allowed quantitative measurement of the stability of these host-guest inclusion complexes. Particularly, we have established a competitive interaction in which one host-guest inclusion complex pair is much more stable than another host-guest inclusion complex pair. The stability constants for the three host-guest inclusion complexes of TMeQ[6]-G1, TMeQ[6]-G2, and TMeQ[6]-G3 are approximately 2x10(6), 60.7, and 19.9 mol-1.L, respectively. To understand how subtle differences in the structure of the title guests lead to a significant difference in the stability of the corresponding host-guest inclusion complexes with the TMeQ[6], ab initio theoretical calculations have been performed, not only for the gas phase but also the solution phase (water as solvent) in all cases. The calculation results revealed that when the phenyl moiety of the three pyridine derivate guests was included, the host-guest complexation reached the minimum, and the corresponding energy differences for the formation of the title host-guest inclusion complexes are qualitatively consistent with the experimental results.     

Complexation of ferrocene derivatives by the cucurbit[7]uril host: a comparative study of the cucurbituril and cyclodextrin host families

The formation of inclusion complexes between cucurbit[7]uril (CB[7]) and ferrocene and its derivatives has been investigated. The X-ray crystal structure of the 1:1 inclusion complex between ferrocene and CB[7] revealed that the guest molecule resides in the host cavity with two different orientations. Inclusion of a set of five water-soluble ferrocene derivatives in CB[7] was investigated by 1H NMR spectroscopy and calorimetric and voltammetric techniques. Our data indicate that all neutral and cationic guests form highly stable inclusion complexes with CB[7], with binding constants in the 10(9)-10(10) M(-)(1) and 10(12)-10(13) M(-1) ranges, respectively. However, the anionic ferrocenecarboxylate, the only negatively charged guest among those surveyed, was not bound by CB[7] at all. These results are in sharp contrast to the known binding behavior of the same guests to beta-cyclodextrin (beta-CD), since all the guests form stable inclusion complexes with beta-CD, with binding constants in the range 10(3)-10(4) M(-1). The electrostatic surface potentials of CB[6], CB[7], and CB[8] and their size-equivalent CDs were calculated and compared. The CD portals and cavities exhibit low surface potential values, whereas the regions around the carbonyl oxygens in CBs are significantly negative, which explains the strong affinity of CBs for positively charged guests and also provides a rationalization for the rejection of anionic guests. Taken together, our data suggest that cucurbiturils may form very stable complexes. However, the host-guest interactions are very sensitive to some structural features, such as a negatively charged carboxylate group attached to the ferrocene residue, which may completely disrupt the stability of the complexes.     

Cucurbit[7]uril host-guest complexes with small polar organic guests in aqueous solution

The host-guest stability constants for the inclusion of a series of small neutral polar organic guests in cucurbit[7]uril (CB[7]) have been determined in aqueous solution by (1)H NMR titrations. The dependence of the stability constant on the nature of the guests indicates that hydrophobic and dipole-quadrupole interactions are responsible for the binding. The complexation-induced chemical shift changes in the guest proton resonances, coupled with energy-minimization calculations, suggest that the guests are located such that their dipole moment is aligned perpendicular with the quadrupole moment of the CB[7] host. The stability constants for acetone and acetophenone decrease in the presence of Na(+) or K(+) cations as a result of cation capping of the CB[7] portals.     

Binding selectivity of cucurbit[7]uril: bis(pyridinium)-1,4-xylylene versus 4,4'-bipyridinium guest sites

The binding interactions between the host cucurbit[7]uril (CB7) and a series of linear guests containing bis(pyridinium)-1,4-xylylene and/or 4,4'-bipyridinium residues were investigated by (1)H NMR spectroscopy. CB7 was found to exhibit considerable binding selectivity for bis(pyridinium)-1,4-xylylene over 4,4'-bipyridinium sites. New pseudo-rotaxane and rotaxane compounds were synthesized utilizing the host-guest interactions between CB7 and the surveyed guests. [structure: see text]