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.     

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.     

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.     

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.     

水溶性六元瓜环衍生物与1,ω-亚烷基吡啶主客体配合物的^1HNMR及晶体结构

利用^1HNMR技术以及单晶X衍射技术考察对称四甲基取代六元瓜环（TMeQ[6]）与几种1,ω-亚烷基吡啶阳离子（ω=2,4,6,8,10）客体的相互作用．在这些包结配合物中,TMeQ[6]的端口效应以及空腔效应同时存在,其主客体作用模式随着客体亚烷基碳链长短不一而各不相同．对于客体1,2-二乙基吡啶（Edpy）,TMeQ[6]包结Edpy的带正电荷的吡啶环部分,形成一不对称的包结配合物;对于客体1,4-二丁基吡啶（Bdpy）,TMeQ[6]选择性包结Bdpy的吡啶环部分或烷基部分存在竞争作用和快速交换;而具有较长碳链的客体1,6-二己基吡啶（Hdpy）和1,8-二丁庚基吡啶（Odpy）与TMeQ[6]通过空腔的疏水作用以及外部的离子-偶极作用形成稳定的类轮烷包结配合物;客体1,10-二癸基吡啶（Ddpy）的两个吡啶环分别被两个TMeQ[6]包结形成哑铃型的包结配合物．     

水溶性六元瓜环衍生物与1,ω-亚烷基吡啶主客体配合物的~1H NMR及晶体结构

利用1HNMR技术以及单晶X衍射技术考察对称四甲基取代六元瓜环(TMeQ[6])与几种1,ω-亚烷基吡啶阳离子(ω=2,4,6,8,10)客体的相互作用.在这些包结配合物中,TMeQ[6]的端口效应以及空腔效应同时存在,其主客体作用模式随着客体亚烷基碳链长短不一而各不相同.对于客体1,2-二乙基吡啶(Edpy),TMeQ[6]包结Edpy的带正电荷的吡啶环部分,形成一不对称的包结配合物;对于客体1,4-二丁基吡啶(Bdpy),TMeQ[6]选择性包结Bdpy的吡啶环部分或烷基部分存在竞争作用和快速交换;而具有较长碳链的客体1,6-二己基吡啶(Hdpy)和1,8-二丁庚基吡啶(Odpy)与TMeQ[6]通过空腔的疏水作用以及外部的离子-偶极作用形成稳定的类轮烷包结配合物;客体1,10-二癸基吡啶(Ddpy)的两个吡啶环分别被两个TMeQ[6]包结形成哑铃型的包结配合物.     

对称四甲基六元瓜环与1-丁基-4,4’-联吡啶的超分子自组装

设计合成了客体分子1-丁基-4,4’-联吡啶溴化物(BV+),利用核磁共振、紫外-可见吸收光谱、热重分析及X射线单晶衍射研究其与对称四甲基六元瓜环(TMeQ[6])的超分子自组装及形成的主客体包结配合物的结构特征.结果表明,在溶液中及固体状态下,TMeQ[6]均包结BV+的烷基链部分形成1∶1包结配合物.     

对称二环己基取代六元瓜环与3-吡啶甲酰肼的超分子自组装

本工作以对称二环己基取代六元瓜环(CyH2Q[6])为主体分子,3-吡啶甲酰肼(NH)为客体分子,利用核磁共振(1H NMR)、等温滴定量热(ITC)、基质辅助激光解吸电离飞行时间质谱(MALDI-TOF)研究客体分子与瓜环在水溶液中形成的物质的量比为1∶1的稳定配合物;用X-射线单晶衍射可以观察到客体分子通过离子-偶...     

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.     

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.     

Kinetic and thermodynamic inclusion complexes of symmetric teramethyl-substituted cucurbit[6]uril with HCl salts of N,N′-bis(pyridylmethyl)-1,6-hexanediamine

The host–guest interaction of symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril (TMeQ[6]) with the hydrochloride salts of N,N′-bis(4-pyridylmethyl)-1,6-hexanediamine (P6), N,N′-bis(3-pyridyl-methyl)-1,6-hexanediamine (M6) and N,N′-bis(2-pyridylmethyl)-1,6-hexanediamine (O6) was investigated via single crystal X-ray diffraction, ¹H NMR spectroscopy, electronic absorption spectroscopy and fluorescence spectroscopy. Single crystal X-ray diffraction showed that the hexyl moiety of P6 or M6 was incorporated in the cavity of TMeQ[6], while the two pyridylmethyl moieties of O6 were incorporated in the TMeQ[6] cavity in the solid state. The ¹H NMR results in aqueous solution revealed that the TMeQ[6]-P6 and TMeQ[6]-M6 host–guest interaction systems produce a kinetic dumbbell-shaped inclusion complex at the initial stage and then an equilibrium pseudorotaxane-shaped inclusion complex as the only product after heating. However, only the pseudorotaxane-shaped inclusion complex was observed for the TMeQ[6]-O6 host–guest interaction system. Aqueous absorption spectrophotometric analysis showed that the dumbbell-shaped inclusion complexes were stable at pH 5.6, had a host–guest ratio of 2:1 and formed quantitatively at ～10¹¹ l²/mol² for the TMeQ[6]-M6 and TMeQ[6]-O6 systems. The transformation from dumbbell to pseudorotaxane-shaped inclusion complexes for the TMeQ[6]-P6 and TMeQ[6]-M6 host–guest systems yielded activation energies of 59.35 ± 1.55 and 78.7 ± 3.45 kJ/mol, respectively. The pseudorotaxane-shaped inclusion complexes were stable at pH 5.6, had a host–guest ratio of 1:1 and formed quantitatively at ～10⁷ l/mol for the TMeQ[6]-M6 and TMeQ[6]-P6 systems.     

Host–guest complexes of some cucurbit[n]urils with the hydrochloride salts of some imidazole derivatives

Interaction between the normal cucurbit[n]urils (n = 6,7,8; Q[6], Q[7], Q[8]) and a sym-tetramethyl-substituted cucurbit[6]uril derivative (TMeQ[6]) with the hydrochloride salts of some imidazole derivatives N-(4-hydroxylphenyl)imidazole (g1), N-(4-aminophenyl)imidazole (g2), 2-phenylimidazole (g3) in aqueous solution was investigated by using ¹H NMR spectroscopy, electronic absorption spectroscopy and fluorescence spectroscopy, as well as by using a single crystal X-ray diffraction determination. The ¹H NMR spectra analysis established a basic interaction model in which inclusion complexes with a host:guest ratio of 1:1 forms for the Q[6]s and Q[7] cases, while with a host:guest ratio of 1:2 form for the Q[8] cases. It was common that the hosts selectively bound the phenyl moiety of the guests. Absorption spectrophotometric and fluorescence spectroscopic analysis in aqueous solution defined the stability of the host–guest inclusion complexes at pH 5.8 with a host:guest ratio of 1:1 form quantitatively as logK values between 4 and 5 for the smaller hosts Q[6 or 7]s, while with a host:guest ratio of 1:2 form quantitatively as logK values between 11 and 12 for the host Q[8]. Two single crystal X-ray structures of the inclusion complexes TMeQ[6]-g2 · HCl and TMeQ[6]-g3 · HCl showed the phenyl moiety of these two guests inserted into the host cavity, which supported particularly the ¹H NMR spectroscopic study in solution.     

Host–guest complexes of various cucurbit[n]urils with the hydrochloride salt of 2,4-diaminoazobenzene

The interaction products of normal cucurbit[n]urils (n = 7, 8; Q[7] Q[8]) and a sym- tetramethyl-substituted cucurbit[6]uril derivative (TMeQ[6]) with the hydrochloride salts of 2,4-diaminoazobenzene (g·HCl) were investigated in aqueous solution using ¹H NMR spectroscopy, electronic absorption spectroscopy, as well as single crystal X-ray diffraction. The ¹H NMR spectra analysis established a basic interaction model in which inclusion complexes with a host:guest ratio of 1:1 form for the TMeQ[6] and Q[7] cases, while they form with a host:guest ratio of 1:2 for the Q[8] case. Commonly, the hosts selectively bound to the phenyl moieties of the guests. Absorption spectrophotometric analysis in aqueous solution defined the stability of the host–guest inclusion complexes at pH 3.2. Quantitatively, at this pH, complexes with a host:guest ratio of 1:1—those with smaller hosts TMeQ[6] and Q[7]—formed with logK values between 6 and 7. That with host Q[8] and a host:guest ratio of 1:2 formed with a logK value of 10.8. Single crystal X-ray structures of the inclusion complexes TMeQ[6]–g·HCl and Q[8]–g·HCl showed the phenyl moiety of the guest inserted into the host cavity. This result supports the solution-based ¹H NMR spectroscopic study.     

Host-guest complexes of a water soluble cucurbit[6]uril derivative with some dications of 1,ω-alkyldipyridines: <Superscript>1</Superscript>H NMR and X-ray structures

Interactions between a symmetrical tetramethyl-substituted cucurbit[6]uril (host: TMeQ[6]) and 1,ω-alkylenedipyridine (ω = 2, 4, 6, 8, 10) dicationic guests were investigated using ¹H NMR spectroscopy and single crystal X-ray crystallography. In these inclusion complexes, combined cavity and portal binding in TMeQ[6] were observed, and the length of the bridged alkylene was found to play an important role not only in balancing the overall hydrophilic/hydrophobic interaction between the host and the guest, but also in defining the structure of the resulting inclusion complexes. For the guest 1,2-ethylenedipyridine (Edpy), TMeQ[6] includes a positively charged pyridine ring of Edpy to form an unsymmetrical inclusion complex; for the guest 1,4-butylenedipyridine (Bdpy), TMeQ[6] includes a positively charged pyridine ring of Bdpy, but the different competitive interactions in and between the related inclusion complexes could lead to a fast exchange between the hosts and guests. For the guests with longer bridge chains, such as 1,6-hexamethylenedipyridine (Hdpy) or 1,8-octylenedipyridine (Odpy), a stable pseudorotaxane inclusion complex is formed by combining the hydrophobic cavity and the outer portal dipole-ion interactions. However, for 1,10-decatylenedipyridine (Ddpy), the two TMeQ[6] host molecules include the two end pyridine rings of Ddpy and form a dumbbell inclusion complex. Supported by the National Natural Science Foundation of China (Grant Nos. 20662003 & 20767001), the International Collaborative Project of Guizhou Province (Grant No. 2007400108), the Science Technology Fund of Guizhou Province (Grant No. J-2008-2012) and the Natural Science Youth Foundation of Guizhou University (Grant No. 2007-005)     

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.     

Supramolecular assemblies of cucurbit[n]urils and 4-aminopyridine controlled by cucurbit[n]uril size (n = 5, 6, 7 and 8)

The binding interactions between 4-aminopyridine (4-AP) and a series of cucurbit[n]urils (Q[5], Q[6], TMeQ[6], Q[7], Q[8]) have been studied using ¹H NMR spectroscopy, UV–vis absorption spectroscopy, isothermal titration calorimetry (ITC) and X-ray crystallography. The data indicates that the Q[5]@4-AP complex exhibits exo binding, which is not observed in the other four host-guest complexes. Furthermore, X-ray crystallography clearly reveals how the Q[n]s bind with 4-AP to form complexes, for example Q[5] forms an outer-surface complex, whilst Q[6], TMeQ[6] and Q[7] formed 1:1 host and guest type complexes, and Q[8] formed a stable 1:2 ternary complex due to its large cavity, which can accommodate two 4-AP molecules.     

对称四甲基六元瓜环与2-苄基咪唑啉盐酸盐自组装包合物的晶体结构

以2-苄基-咪唑啉盐酸盐(Benid)为客体,对称四甲基六元瓜环(TMeQ[6])为主体,在水溶液中形成自组装包合物(TMeQ[6]-Benid)的晶体.X-射线单晶衍射实验表明,Benid-TMeQ[6]为单斜晶系,空间群P21,晶胞参数:a=1.18633(5) nm,b=2.06145(6) nm,c=1.35163(5) nm,α=90.00°,β=96.102(2)°,γ=90.00°,V=3.28676 nm3,Z=2,Mr=1626.95,Dc=1.569 g·cm-3,μ=0.169 mm-1,R1=0.0739,Wr2=0.1412.通过多种非共价键弱相互作用,主客体以1:1的包结比形成自组装包合物,客体的苯环被包结在主体的空腔内.1H NMR结果进一步证实了在溶液中也是同样的包结模式,包结稳定常数为7.23×105 mol-1·L.     

Host–guest Complex of a Water-soluble Cucurbit[6]uril Derivative with the Hydrochloride Salt of 3-amino-5-phenylpyrazole

Interaction between tetramethylcucurbit[6]uril and 3-amino-5-phenylpyrazole hydrochloride in aqueous solution has been investigated by using ¹H NMR spectroscopy, electronic absorption spectroscopy and fluorescence spectroscopy, as well as by a single crystal X-ray diffraction determination. The ¹H NMR spectra analysis established a basic interaction model in which an inclusion complex with a host:guest ratio of 1:1 forms, in which the host selectively binds the phenyl moiety of the guest. Absorption spectrophotometric and fluorescence spectroscopic analysis in aqueous solution defined the stability of the host–guest inclusion complexes quantitatively as 6.8 × 10⁵ mol^? 1 L at pH 2.6; the interaction is pH dependent, decreasing as pH rises. The single crystal X-ray structure of the isolated inclusion complex shows the phenyl moiety of the guest inserted into the host cavity, which supports particularly the ¹H NMR spectroscopic study in solution. In the crystal structure of the inclusion complex, the host–guest interaction involves both inter- and intra-complex hydrogen bonding, forming 2:2 dimers that stack in one dimension as supramolecular tubes.     

Host–guest interactions of thiabendazole with normal and modified cucurbituril: 1H NMR,phase solubility and antifungal activity studies

Guest–host inclusion complexes between thiabendazole (TBZ) and cucurbit[7]uril (Q[7]), symmetrical tetra-methylcucurbit[6]uril (TMeQ[6]) and meta-hexamethyl-substituted cucurbit[6]uril (HMeQ[6]) in aqueous solution were investigated by ¹H NMR spectroscopy and phase solubility studies. The antifungal activities of the inclusion complexes were also determined. Analysis of the ¹H NMR spectra revealed that the host Q[7] selectively binds the benzimidazole ring moiety of the guest molecule and that the thiazole ring is encapsulated into the cavities of TMeQ[6] and HMeQ[6]. Phase solubility diagrams were analysed using rigorous procedures to obtain estimates of the complex formation constants for Q[n]-TBZ complexation. The phase solubility studies showed that TBZ solubility increased as a function of Q[7], TMeQ[6] and HMeQ[6] concentrations. We found that complexation of TBZ with Q[n] increased the inhibitory effect of TBZ on the growth of Fusarium graminearum. Our results thus demonstrate that complexation of TBZ with Q[n] could be used to improve the solubility and antifungal activity of TBZ.