Self-assembled complexes between cage com-pounds cucurbit[n = 5—8]urils and hexamethylenetetramine were studied by using NMR techniques. Experimental results reveal that hexamethylenetetramine can lid cucurbit[5]uril...Self-assembled complexes between cage com-pounds cucurbit[n = 5—8]urils and hexamethylenetetramine were studied by using NMR techniques. Experimental results reveal that hexamethylenetetramine can lid cucurbit[5]uril to forming self-assembled capsules in which nothing is encap-sulated yet; the cavity of the cucurbit[7]uril can accommo-date a hexamethylenetetramine molecule to form a self- assembled host-guest inclusion. Moreover, both the cavity interaction of the cucurbit[7]uril with hexamethylenetetra-mine稨Cl and the portal interaction of the dipole carbonyl of the cucurbit[7]uril with hexamethylenetetramine稨Cl lead to form self-assembled capsules in which the hexamethylene-tetramine稨Cl are encapsulated in the hexamethylenetetra-mine稨Cl lidded cucurbit[7]uril. Although the structures of the portal and cavity to cucurbit[5]uril are similar, there is no obvious interaction between decamethylcucurbit[5]uril and hexamethylenetetramine, and also between cucurbit [6]uril or cucurbit[8]uril and hexamethylenetetramine.展开更多
Binding of non-activated alkyl halides(2-20)in water-soluble cavitand(1)through supramolecular forces is here reported,with emphasis on the role of size and polarizability of the halogen atom in the formation of intra...Binding of non-activated alkyl halides(2-20)in water-soluble cavitand(1)through supramolecular forces is here reported,with emphasis on the role of size and polarizability of the halogen atom in the formation of intramolecular C-H hydrogen bonds in confined spaces.Rare reverse affinity in water(RI<RBr<RCl)is surprisingly observed for the more water-soluble short alkyl halides in dynamic open-ended containers.Competitive bindings and theoretical calculations confirm the unusual selectivity and the presence of C-H hydrogen bonds in non-activated systems for the first time,pointing out the importance and effect of subtle forces on molecular recognition in confined spaces.展开更多
The mechanism for the conformational conversion of 1,3-dioxane guest encapsulated inside a capsular host was theoretically investigated using semiempirical PM3 method and DFT methods. The free-state process of the con...The mechanism for the conformational conversion of 1,3-dioxane guest encapsulated inside a capsular host was theoretically investigated using semiempirical PM3 method and DFT methods. The free-state process of the conformational conversion of 1,3-dioxane was also investigated to make a comparison between the two different states using the same theory. The influences of the inner phase of the capsule on the conformational conversion of guest molecule were discussed via analyzing the comparative results. It was found that the capsular host could accommodate 1,3-dioxane within its cavity by the weak attractive interactions between host and guest, and it responds to the conformational conversion of guest by the deformation of hydrogen-bonding seam at the middle of the capsule. When entrapped in the capsule, the guest molecule undergoes the conformational conversion from chair form to twist-boat form slower than that under the free condition. The deformation of the capsule is favorable to maximize the attractive interactions between host and guest.展开更多
Two functionalized calixarenes in cone conformation L 2-3 have been synthesized and their intramolecular inclusion complexes (1∶1) with organic neutral molecules CH 3CN and CH 3NO 2 have been prepared and c...Two functionalized calixarenes in cone conformation L 2-3 have been synthesized and their intramolecular inclusion complexes (1∶1) with organic neutral molecules CH 3CN and CH 3NO 2 have been prepared and characterized, respectively. The X-ray crystallographic analysis shows that L 2 in L 2·CH 3CN·C 2H 5OH has C 4 symmestry and L 3 in L 3·CH 3NO 2 exhibits C 2 symmestry. The CH-π aromatic interactions between the CH group of the guest and the phenyl rings of the calix backbond have been proved to be able to stabilize the intramolecular inclusion complexes formed. The interaction is directional, but it is independent of the acidity of the guest. To gain information on CH-π interactions, suitable geometrical parameters have been calculated from the crystal data of intramolecular inclusion complexes. The results show that L 3·CH 3NO 2 with L 3 in C 2 symmestry can also be bound stably in the intramolecular inclusion complex, being consistent with the thermal analysis. The geometrical parameters and the results of the thermal analysis of L 1·CH 3CN and L 1·CH 3NO 2 were also given and discussed.展开更多
3-Indolyl acetate can be soluhilized in dilute aqueous solution of beta cy clodextrin. dueto the formation of host-guest complex through hydrophobic interaction between the indolyl groupand the inside cave of the cycl...3-Indolyl acetate can be soluhilized in dilute aqueous solution of beta cy clodextrin. dueto the formation of host-guest complex through hydrophobic interaction between the indolyl groupand the inside cave of the cyclodextrin molecule. The thermodynamic pararneters of thecomplexing process can be estimated utilizing the spectrophotometric data.展开更多
Supramolecular incorporation of lanthanide complex has been obtained by loading of organic ligand into Eu3+-exchanged zeolite L. This was achieved by a two-step procedure: (1) zeolite L was ion-exchanged with Eu(Ⅲ) i...Supramolecular incorporation of lanthanide complex has been obtained by loading of organic ligand into Eu3+-exchanged zeolite L. This was achieved by a two-step procedure: (1) zeolite L was ion-exchanged with Eu(Ⅲ) ions; (2) organic ligand was then loaded into the channels of the Eu3+-exchanged zeolite by gas diffusion procedure. Loading of ligand into the channels of zeolite L was confirmed by element analysis. Luminescence spectroscopy has confirmed that lanthanide complex are formed in the nanochannels of zeolite L crystals. In addition to the sharp emissions of lanthanide ions, broad band ranged from 350～500 nm can also be observed. This study provides alternative method for fabricating full-color display materials.展开更多
基金supported by the Natural Science Foundation of Guizhou Province(Grant No.20013025)the Key Project of the Natural Science Foundation of Guizhou Province(Grant No.20023004)+1 种基金the International Collaborative Project of Guizhou Province(Grant No.200211003)and the National Natural Science Foundation of China(Grant No.20261002)
文摘Self-assembled complexes between cage com-pounds cucurbit[n = 5—8]urils and hexamethylenetetramine were studied by using NMR techniques. Experimental results reveal that hexamethylenetetramine can lid cucurbit[5]uril to forming self-assembled capsules in which nothing is encap-sulated yet; the cavity of the cucurbit[7]uril can accommo-date a hexamethylenetetramine molecule to form a self- assembled host-guest inclusion. Moreover, both the cavity interaction of the cucurbit[7]uril with hexamethylenetetra-mine稨Cl and the portal interaction of the dipole carbonyl of the cucurbit[7]uril with hexamethylenetetramine稨Cl lead to form self-assembled capsules in which the hexamethylene-tetramine稨Cl are encapsulated in the hexamethylenetetra-mine稨Cl lidded cucurbit[7]uril. Although the structures of the portal and cavity to cucurbit[5]uril are similar, there is no obvious interaction between decamethylcucurbit[5]uril and hexamethylenetetramine, and also between cucurbit [6]uril or cucurbit[8]uril and hexamethylenetetramine.
基金supported by the National Natural Science Foundation of China(Nos.22071144 and 21801164)Shanghai Scientific and Technological Committee(No.22010500300)the Program for Professor of Special Appointment(Dongfang Scholaship)of the Shanghai Education Committee。
文摘Binding of non-activated alkyl halides(2-20)in water-soluble cavitand(1)through supramolecular forces is here reported,with emphasis on the role of size and polarizability of the halogen atom in the formation of intramolecular C-H hydrogen bonds in confined spaces.Rare reverse affinity in water(RI<RBr<RCl)is surprisingly observed for the more water-soluble short alkyl halides in dynamic open-ended containers.Competitive bindings and theoretical calculations confirm the unusual selectivity and the presence of C-H hydrogen bonds in non-activated systems for the first time,pointing out the importance and effect of subtle forces on molecular recognition in confined spaces.
基金Supported by the Special Research Fund for the Doctoral Program of Higher Education(No20040010008)the Scientific Research Fund of Beijing University of Chemical Technology(NoQN0411)
文摘The mechanism for the conformational conversion of 1,3-dioxane guest encapsulated inside a capsular host was theoretically investigated using semiempirical PM3 method and DFT methods. The free-state process of the conformational conversion of 1,3-dioxane was also investigated to make a comparison between the two different states using the same theory. The influences of the inner phase of the capsule on the conformational conversion of guest molecule were discussed via analyzing the comparative results. It was found that the capsular host could accommodate 1,3-dioxane within its cavity by the weak attractive interactions between host and guest, and it responds to the conformational conversion of guest by the deformation of hydrogen-bonding seam at the middle of the capsule. When entrapped in the capsule, the guest molecule undergoes the conformational conversion from chair form to twist-boat form slower than that under the free condition. The deformation of the capsule is favorable to maximize the attractive interactions between host and guest.
基金theNationalNaturalScienceFoundationofChina (No .2 9872 0 34 )andtheNaturalScienceFoundationofHenan ,China
文摘Two functionalized calixarenes in cone conformation L 2-3 have been synthesized and their intramolecular inclusion complexes (1∶1) with organic neutral molecules CH 3CN and CH 3NO 2 have been prepared and characterized, respectively. The X-ray crystallographic analysis shows that L 2 in L 2·CH 3CN·C 2H 5OH has C 4 symmestry and L 3 in L 3·CH 3NO 2 exhibits C 2 symmestry. The CH-π aromatic interactions between the CH group of the guest and the phenyl rings of the calix backbond have been proved to be able to stabilize the intramolecular inclusion complexes formed. The interaction is directional, but it is independent of the acidity of the guest. To gain information on CH-π interactions, suitable geometrical parameters have been calculated from the crystal data of intramolecular inclusion complexes. The results show that L 3·CH 3NO 2 with L 3 in C 2 symmestry can also be bound stably in the intramolecular inclusion complex, being consistent with the thermal analysis. The geometrical parameters and the results of the thermal analysis of L 1·CH 3CN and L 1·CH 3NO 2 were also given and discussed.
文摘3-Indolyl acetate can be soluhilized in dilute aqueous solution of beta cy clodextrin. dueto the formation of host-guest complex through hydrophobic interaction between the indolyl groupand the inside cave of the cyclodextrin molecule. The thermodynamic pararneters of thecomplexing process can be estimated utilizing the spectrophotometric data.
文摘Supramolecular incorporation of lanthanide complex has been obtained by loading of organic ligand into Eu3+-exchanged zeolite L. This was achieved by a two-step procedure: (1) zeolite L was ion-exchanged with Eu(Ⅲ) ions; (2) organic ligand was then loaded into the channels of the Eu3+-exchanged zeolite by gas diffusion procedure. Loading of ligand into the channels of zeolite L was confirmed by element analysis. Luminescence spectroscopy has confirmed that lanthanide complex are formed in the nanochannels of zeolite L crystals. In addition to the sharp emissions of lanthanide ions, broad band ranged from 350～500 nm can also be observed. This study provides alternative method for fabricating full-color display materials.
