Mono-alkyl-functionalized pillar[5]arenes PI, P2, and P3 were synthesized by click reaction, which exhibited different self-assembly behavior in polar solvent DMSO. Stable pseudo[ 1 ]rotaxane was formed by the self-co...Mono-alkyl-functionalized pillar[5]arenes PI, P2, and P3 were synthesized by click reaction, which exhibited different self-assembly behavior in polar solvent DMSO. Stable pseudo[ 1 ]rotaxane was formed by the self-complexation from P1 or P2, whereas, concentration-dependent pseudorotaxane structures were generated by P3 which bearing more flexible side chain. Interestingly, the obtained pseudo[1]rotaxanes exhibited a dynamic fast assembly process upon adding NaBF4, resulting in the formation of Na＋-induced pseudorotaxanes.展开更多
This research article is focused on the recognition interaction of a new host naphtho-21-crown-7 and four sec-ondary dialkylammonium salts.In acetone,they can form 1∶1 host-guest complexes which belong to slow-exchan...This research article is focused on the recognition interaction of a new host naphtho-21-crown-7 and four sec-ondary dialkylammonium salts.In acetone,they can form 1∶1 host-guest complexes which belong to slow-exchange systems.We also found the differences of binding affinity and binding selectivity between the host and its complementary guest moieties,which could be ascribed to the aromaticπ-πstacking effect and the acidity increase of N-methylene and ammonium hydrogens due to the increasing electron withdrawing ability from butyl to methoxyphenyl to phenyl to p-cyanophenyl substituents in the recognition motif.展开更多
A novel[2]pseudorotaxane of cucurbit[6]uril(CB[6])and 1-butyl-3-methyl-imidazolium bromide([C4mim]Br)was synthesized by directly mixing the host and the guest molecules in non-aqueous system.Structural characteri-zati...A novel[2]pseudorotaxane of cucurbit[6]uril(CB[6])and 1-butyl-3-methyl-imidazolium bromide([C4mim]Br)was synthesized by directly mixing the host and the guest molecules in non-aqueous system.Structural characteri-zations of the[2]pseudorotaxane were carried out by 1D,2D NMR and X-ray crystallography techniques both in solution and in crystal structure.The crystal structure demonstrated that CB[6]and[C4mim]Br formed a complex with the ratio 1∶1,in which one guest[C4mim]Br was included inside the CB[6],while two other[C4mim]Br molecules were free and surrounded the[2]pseudorotaxane as solvent molecules,which could stabilize the crystal structure through hydrogen bonds.Moreover,parallel solvent channels consisting by free[C4mim]Br molecules occupied the pores among the frame of the pseudorotaxanes and formed zigzag lines in the crystal structure.[C4mim]Br can serve as not only the guest reactant but also the solvent in the formation of[2]pseudorotaxane for-mation.展开更多
The [2] pseudorotaxane of cucurbit[6]uril(CB[6]) with guest molecule 1,6-bis(imidazol-1-yl)hexane dihydrochloride(BIMH-Cl) made pBR322 DNA hydrolyzed efficiently in physiological environment. The cleavage mechanism wa...The [2] pseudorotaxane of cucurbit[6]uril(CB[6]) with guest molecule 1,6-bis(imidazol-1-yl)hexane dihydrochloride(BIMH-Cl) made pBR322 DNA hydrolyzed efficiently in physiological environment. The cleavage mechanism was proposed that was a cooperation process of the CB[6] molecule and the guest BIMH molecule. In this mechanism, the protonated imidazole might bind DNA via the electrostatic interactions and the CB[6] glycoluril carbonyl oxygen atoms activated a water molecule to attack the phosphorus atom.展开更多
A twin-axial hetero[5]pseudorotaxane was constructed based on 1-hexyl-4,40-bipyridinium guest 1 and cucurbit[8]uril（CB[8]）and a-cyclodextrin（a-CD）.In its structure,CB[8]included two bipyridinium units to realize t...A twin-axial hetero[5]pseudorotaxane was constructed based on 1-hexyl-4,40-bipyridinium guest 1 and cucurbit[8]uril（CB[8]）and a-cyclodextrin（a-CD）.In its structure,CB[8]included two bipyridinium units to realize the twin-axial mode,and the hexyl chain was threaded into the cavity of a-CD.The[5]pseudorotaxane contains two types of macrocyclic hosts while the single axial and twin axial modes co-exist in its structure.The transformation of[5]pseudorotaxane could be realized by the addition of acid and 2,6-dihydroxynaphthalene（HN）.展开更多
Sym-bis（benzimidazole）-2,2＇-ethylene cations act as a new axle template for threading cucurbit[6]uril derivatives on,forming[2]pseudorotaxane and[3]pseudorotaxane.These new complexes have been studied using 1 H NMR...Sym-bis（benzimidazole）-2,2＇-ethylene cations act as a new axle template for threading cucurbit[6]uril derivatives on,forming[2]pseudorotaxane and[3]pseudorotaxane.These new complexes have been studied using 1 H NMR,UV-vis absorption spectroscopy and X-ray analysis.Changes in the 1 H NMR spectra indicate that the two types of pseudorotaxane can be formed by varying the host concentration. UV-vis absorption titration experiments at different pH values demonstrate that interesting pK_a shifts of the bis-benzimidazole derivatives can be induced by the host-guest complexation.The associated constants were calculated to be 2.81×10^4 L/mol and 9.06×10^6 L/mol for the[2]pseudorotaxanes and ｜3]pseudorotaxanes,respectively.Furthermore,X-ray diffraction studies of the solid state structures provide unequivocal proof of the host concentration dependent pseudorotaxane,which is strongly in line with the evidences in solution.展开更多
基金the financial support from the National Natural Science Foundation of China(Nos.21472089,21572101)the National Natural Science Foundation of Jiangsu(No.BK20140595)
文摘Mono-alkyl-functionalized pillar[5]arenes PI, P2, and P3 were synthesized by click reaction, which exhibited different self-assembly behavior in polar solvent DMSO. Stable pseudo[ 1 ]rotaxane was formed by the self-complexation from P1 or P2, whereas, concentration-dependent pseudorotaxane structures were generated by P3 which bearing more flexible side chain. Interestingly, the obtained pseudo[1]rotaxanes exhibited a dynamic fast assembly process upon adding NaBF4, resulting in the formation of Na＋-induced pseudorotaxanes.
基金This work was supported by the National Natural Science Foundation of China(Nos.21172166 and 21203135)China Postdoctoral Science Foundation(No.2013M541456)+1 种基金Natural Science Foundation of Zhejiang Province(No.LY14B020012)University Students'Science and Technology Innovation Program of Zhejiang Province(No.2013R428016).
文摘This research article is focused on the recognition interaction of a new host naphtho-21-crown-7 and four sec-ondary dialkylammonium salts.In acetone,they can form 1∶1 host-guest complexes which belong to slow-exchange systems.We also found the differences of binding affinity and binding selectivity between the host and its complementary guest moieties,which could be ascribed to the aromaticπ-πstacking effect and the acidity increase of N-methylene and ammonium hydrogens due to the increasing electron withdrawing ability from butyl to methoxyphenyl to phenyl to p-cyanophenyl substituents in the recognition motif.
基金support by the National Natural Science Foundation of China(Nos.21202037,21401044)Doctor Fund of Henan University of Technology(No.2013BS066).
文摘A novel[2]pseudorotaxane of cucurbit[6]uril(CB[6])and 1-butyl-3-methyl-imidazolium bromide([C4mim]Br)was synthesized by directly mixing the host and the guest molecules in non-aqueous system.Structural characteri-zations of the[2]pseudorotaxane were carried out by 1D,2D NMR and X-ray crystallography techniques both in solution and in crystal structure.The crystal structure demonstrated that CB[6]and[C4mim]Br formed a complex with the ratio 1∶1,in which one guest[C4mim]Br was included inside the CB[6],while two other[C4mim]Br molecules were free and surrounded the[2]pseudorotaxane as solvent molecules,which could stabilize the crystal structure through hydrogen bonds.Moreover,parallel solvent channels consisting by free[C4mim]Br molecules occupied the pores among the frame of the pseudorotaxanes and formed zigzag lines in the crystal structure.[C4mim]Br can serve as not only the guest reactant but also the solvent in the formation of[2]pseudorotaxane for-mation.
文摘The [2] pseudorotaxane of cucurbit[6]uril(CB[6]) with guest molecule 1,6-bis(imidazol-1-yl)hexane dihydrochloride(BIMH-Cl) made pBR322 DNA hydrolyzed efficiently in physiological environment. The cleavage mechanism was proposed that was a cooperation process of the CB[6] molecule and the guest BIMH molecule. In this mechanism, the protonated imidazole might bind DNA via the electrostatic interactions and the CB[6] glycoluril carbonyl oxygen atoms activated a water molecule to attack the phosphorus atom.
基金the National Basic Research Program of China (973 Program, No. 2011CB932500)the National Natural Science Foundation of China (Nos. 20932004 and 91227107) for fnancial support
文摘A twin-axial hetero[5]pseudorotaxane was constructed based on 1-hexyl-4,40-bipyridinium guest 1 and cucurbit[8]uril（CB[8]）and a-cyclodextrin（a-CD）.In its structure,CB[8]included two bipyridinium units to realize the twin-axial mode,and the hexyl chain was threaded into the cavity of a-CD.The[5]pseudorotaxane contains two types of macrocyclic hosts while the single axial and twin axial modes co-exist in its structure.The transformation of[5]pseudorotaxane could be realized by the addition of acid and 2,6-dihydroxynaphthalene（HN）.
基金supported by the National Natural Science Foundation of China(No,21272045)the Natural Science Foundation of Guizhou Province and Guizhou Universitythe "Chun-Hui" Funds of the Chinese Ministry of Education are gratefully acknowledged
文摘Sym-bis（benzimidazole）-2,2＇-ethylene cations act as a new axle template for threading cucurbit[6]uril derivatives on,forming[2]pseudorotaxane and[3]pseudorotaxane.These new complexes have been studied using 1 H NMR,UV-vis absorption spectroscopy and X-ray analysis.Changes in the 1 H NMR spectra indicate that the two types of pseudorotaxane can be formed by varying the host concentration. UV-vis absorption titration experiments at different pH values demonstrate that interesting pK_a shifts of the bis-benzimidazole derivatives can be induced by the host-guest complexation.The associated constants were calculated to be 2.81×10^4 L/mol and 9.06×10^6 L/mol for the[2]pseudorotaxanes and ｜3]pseudorotaxanes,respectively.Furthermore,X-ray diffraction studies of the solid state structures provide unequivocal proof of the host concentration dependent pseudorotaxane,which is strongly in line with the evidences in solution.
