1
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He T, Hu X, Liu S. A High-Affinity and Removable Iminium Dication Guest for Recycling of Cucurbit[7]uril Materials. Org Lett 2023; 25:246-250. [PMID: 36576805 DOI: 10.1021/acs.orglett.2c04096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
An iminium dication 1 was designed as a high-affinity and easily removable guest for cucurbit[7]uril (CB[7]). X-ray crystallographic analysis shows that maximized N+···O═C ion-dipole interactions and perfect packing coefficient are responsible for the high affinity of 1 for CB[7] (Ka > 1011 M-1). Under alkaline conditions, included 1 in CB[7]·1 is hydrolyzed into 2,6-adamantanedione and pyrrolidine that can be fully removed by further extraction, enabling the recycling of CB[7] materials.
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Affiliation(s)
- Tianci He
- School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Xianchen Hu
- School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Simin Liu
- School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, China.,The State Key Laboratory of Refractories and Metallurgy, Institute of Advanced Materials and Nanotechnology, Wuhan University of Science and Technology, Wuhan 430081, China
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2
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Tomeček J, Čablová A, Hromádková A, Novotný J, Marek R, Durník I, Kulhánek P, Prucková Z, Rouchal M, Dastychová L, Vícha R. Modes of Micromolar Host-Guest Binding of β-Cyclodextrin Complexes Revealed by NMR Spectroscopy in Salt Water. J Org Chem 2021; 86:4483-4496. [PMID: 33648337 DOI: 10.1021/acs.joc.0c02917] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Multitopic supramolecular guests with finely tuned affinities toward widely explored cucurbit[n]urils (CBs) and cyclodextrins (CDs) have been recently designed and tested as functional components of advanced supramolecular systems. We employed various spacers between the adamantane cage and a cationic moiety as a tool for tuning the binding strength toward CB7 to prepare a set of model guests with KCB7 and Kβ-CD values of (0.6-5.0) × 1010 M-1 and (0.6-2.6) × 106 M-1, respectively. These accessible adamantylphenyl-based binding motifs open a way toward supramolecular components with an outstanding affinity toward β-cyclodextrin. 1H NMR experiments performed in 30% CaCl2/D2O at 273 K along with molecular dynamics simulations allowed us to identify two arrangements of the guest@β-CD complexes. The approach, joining experimental and theoretical methods, provided a better understanding of the structure of cyclodextrin complexes and related molecular recognition, which is highly important for the rational design of drug delivery systems, molecular sensors and switches.
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Affiliation(s)
- Josef Tomeček
- Department of Chemistry, Faculty of Technology, Tomas Bata University in Zlín, Vavrečkova 275, 760 01 Zlín, Czech Republic
| | - Andrea Čablová
- Department of Chemistry, Faculty of Technology, Tomas Bata University in Zlín, Vavrečkova 275, 760 01 Zlín, Czech Republic
| | - Aneta Hromádková
- Department of Chemistry, Faculty of Technology, Tomas Bata University in Zlín, Vavrečkova 275, 760 01 Zlín, Czech Republic
| | - Jan Novotný
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Radek Marek
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Ivo Durník
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Petr Kulhánek
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Zdeňka Prucková
- Department of Chemistry, Faculty of Technology, Tomas Bata University in Zlín, Vavrečkova 275, 760 01 Zlín, Czech Republic
| | - Michal Rouchal
- Department of Chemistry, Faculty of Technology, Tomas Bata University in Zlín, Vavrečkova 275, 760 01 Zlín, Czech Republic
| | - Lenka Dastychová
- Department of Chemistry, Faculty of Technology, Tomas Bata University in Zlín, Vavrečkova 275, 760 01 Zlín, Czech Republic
| | - Robert Vícha
- Department of Chemistry, Faculty of Technology, Tomas Bata University in Zlín, Vavrečkova 275, 760 01 Zlín, Czech Republic
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3
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Sueishi Y, Hagiwara S, Matsumoto Y, Hanaya T. Comparative study of inclusion complexation of tetraalkylphosphonium and ammonium salts with cucurbit[7]uril. J INCL PHENOM MACRO 2020. [DOI: 10.1007/s10847-020-01006-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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4
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Chen H, Jin Y, Wang J, Wang Y, Jiang W, Dai H, Pang S, Lei L, Ji J, Wang B. Design of smart targeted and responsive drug delivery systems with enhanced antibacterial properties. NANOSCALE 2018; 10:20946-20962. [PMID: 30406235 DOI: 10.1039/c8nr07146b] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The use of antibiotics has been an epoch-making invention in the past few decades for the treatment of infectious diseases. However, the intravenous injection of antibiotics lacking responsiveness and targeting properties has led to low drug utilization and high cytotoxicity. More importantly, it has also caused the development and spread of drug-resistant bacteria due to repeated medication and increased dosage. The differences in the microenvironments of the bacterial infection sites and normal tissues, such as lower pH, high expression of some special enzymes, hydrogen peroxide and released toxins, etc., are usually used for targeted and controlled drug delivery. In addition, bacterial surface charges, antigens and the surface structures of bacterial cell walls are all different from normal tissue cells. Based on the special bacterial infection microenvironments and bacteria surface properties, a series of drug delivery systems has been constructed for highly efficient drug release. This review summarizes the recent progress in targeted and responsive drug delivery systems for enhanced antibacterial properties.
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Affiliation(s)
- Hao Chen
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China. and Wenzhou Institute of Biomaterials and Engineering, Chinese Academy of Sciences, Wenzhou, 32500, China
| | - Yingying Jin
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
| | - Jingjie Wang
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
| | - Yuqin Wang
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
| | - Wenya Jiang
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
| | - Hangdong Dai
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
| | - Shuaiyue Pang
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
| | - Lei Lei
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
| | - Jian Ji
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Bailiang Wang
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China. and Wenzhou Institute of Biomaterials and Engineering, Chinese Academy of Sciences, Wenzhou, 32500, China
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5
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Characterization of inclusion complexation of various tetraalkylammonium chlorides with cucurbit[7]uril by external high-pressure studies. J INCL PHENOM MACRO 2018. [DOI: 10.1007/s10847-018-0832-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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6
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Honda Y, Hanaya T, Sueishi Y. Inclusion complexation abilities of cucurbit[6]uril for various aromatic amines in the presence of alkali metal cations. J INCL PHENOM MACRO 2017. [DOI: 10.1007/s10847-017-0727-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Babjaková E, Branná P, Kuczyńska M, Rouchal M, Prucková Z, Dastychová L, Vícha J, Vícha R. An adamantane-based disubstituted binding motif with picomolar dissociation constants for cucurbit[n]urils in water and related quaternary assemblies. RSC Adv 2016. [DOI: 10.1039/c6ra23524g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A binding motif based on 1,3-disubstituted adamantane binds cucurbit[8]uril and cucurbit[7]uril with respective values of pK = 12 and 11 to allow formation of quaternary assemblies with inverse arrangements.
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Affiliation(s)
- E. Babjaková
- Department of Chemistry
- Faculty of Technology
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
| | - P. Branná
- Department of Chemistry
- Faculty of Technology
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
| | - M. Kuczyńska
- Department of Chemistry
- Faculty of Technology
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
| | - M. Rouchal
- Department of Chemistry
- Faculty of Technology
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
| | - Z. Prucková
- Department of Chemistry
- Faculty of Technology
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
| | - L. Dastychová
- Department of Chemistry
- Faculty of Technology
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
| | - J. Vícha
- Centre of Polymer Systems
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
| | - R. Vícha
- Department of Chemistry
- Faculty of Technology
- Tomas Bata University in Zlín
- 760 01 Zlín
- Czech Republic
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8
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Barrow SJ, Kasera S, Rowland MJ, del Barrio J, Scherman OA. Cucurbituril-Based Molecular Recognition. Chem Rev 2015; 115:12320-406. [DOI: 10.1021/acs.chemrev.5b00341] [Citation(s) in RCA: 1188] [Impact Index Per Article: 132.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Steven J. Barrow
- Melville
Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Setu Kasera
- Melville
Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Matthew J. Rowland
- Melville
Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Jesús del Barrio
- Melville
Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Oren A. Scherman
- Melville
Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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9
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Radical-Cation Dimerization Overwhelms Inclusion in [n]Pseudorotaxanes. Chemistry 2014; 20:7334-44. [DOI: 10.1002/chem.201400069] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Indexed: 01/19/2023]
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10
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Kwok JC, Macartney DH. Cucurbit[7]uril complexations of bis(isoquinolinium)alkane dications in aqueous solution. Supramol Chem 2013. [DOI: 10.1080/10610278.2013.842645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Julian C. Kwok
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, ON, Canada K7L 4K8
| | - Donal H. Macartney
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, ON, Canada K7L 4K8
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11
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Sueishi Y, Fujita T, Nakatani S, Inazumi N, Osawa Y. The enhancement of fluorescence quantum yields of anilino naphthalene sulfonic acids by inclusion of various cyclodextrins and cucurbit[7]uril. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 114:344-349. [PMID: 23786974 DOI: 10.1016/j.saa.2013.05.052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 04/24/2013] [Accepted: 05/11/2013] [Indexed: 06/02/2023]
Abstract
The association constants (K) for the inclusion complexation of four kinds of cyclodextrins (CDs (β- and γ-), 2,6-di-O-methylated β-CD, and 2,3,6-tri-O-methylated β-CD) and cucurbit[7]uril (CB[7]) with 1,8- and 2,6-anilinonaphthalene sulfonic acids (ANSs) were determined from fluorescence spectra enhanced by inclusion. Various CDs and CB[7] form stable 1:1 inclusion complexes with 1,8- and 2,6-ANSs: K=80-11700 M(-1) for 2,6-ANS and 50-195 M(-1) for 1,8-ANS. The high stability of the inclusion complexes of 2,6-ANS with CB[7] and 2,6-di-O-methylated β-CD is shown. Further, we determined the fluorescence quantum yields (Φ values) for the inclusion complexes of ANSs by using a fluorescence spectrophotometer equipped with a half-moon unit. The Φ values of 1,8- and 2,6-ANSs were largely enhanced by the inclusion of methylated β-CDs and did not correlate with the degree of stability (K) of the inclusion complexes. We characterized the structures of the inclusion complexes by 2D ROESY-NMR measurements. In addition, the microenvironmental polarity inside the hydrophobic CD and CB[7] cavities was evaluated using the fluorescence probe 2,6-ANS. Based on the emission mechanism and the aspect of inclusion in a hydrophobic cavity, we have suggested that the microenvironmental polarity and viscosity for the excited state of ANS plays an important role for the Φ values of inclusion complexes.
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Affiliation(s)
- Yoshimi Sueishi
- Department of Chemistry, Faculty of Science, Okayama University, Kita-ku, Okayama, Japan.
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12
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13
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Macartney DH. Encapsulation of Drug Molecules by Cucurbiturils: Effects on their Chemical Properties in Aqueous Solution. Isr J Chem 2011. [DOI: 10.1002/ijch.201100040] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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14
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Yang Z, Li Y, Zhou H, Li Q, Gao L. Conductivity and Surface Tension Study for Cucurbit[7]uril Inclusion Complex of Cetyltrimethylammonium Chloride in Aqueous Solution. J DISPER SCI TECHNOL 2010. [DOI: 10.1080/01932690903223567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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Wyman IW, Macartney DH. Cucurbit[7]urilhost–guest complexes of cholines and phosphonium cholines in aqueous solution. Org Biomol Chem 2010; 8:253-60. [DOI: 10.1039/b917610a] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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16
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Wyman IW, Macartney DH. Host-guest complexations of local anaesthetics by cucurbit[7]uril in aqueous solution. Org Biomol Chem 2009; 8:247-52. [PMID: 20024155 DOI: 10.1039/b915694a] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The cucurbit[7]uril (CB[7]) host molecule forms very stable host-guest complexes with the local anaesthetics procaine (K(CB[7]) = (3.5 +/- 0.7) x 10(4) dm(3) mol(-1)), tetracaine (K(CB[7]) = (1.5 +/- 0.4) x 10(4) dm(3) mol(-1)), procainamide (K(CB[7]) = (7.8 +/- 1.6) x 10(4) dm(3) mol(-1)), dibucaine (K(CB[7]) = (1.8 +/- 0.4) x 10(5) dm(3) mol(-1)) and prilocaine (K(CB[7]) = (2.6 +/- 0.6) x 10(4) dm(3) mol(-1)) in aqueous solution (pD = 4.75). The stability constants are 2-3 orders of magnitude greater than the values reported for binding by the comparably sized beta-cyclodextrin host molecule. The inclusion by CB[7] raises the first pK(a) values of the anaesthetics by 0.5-1.9 pK units, as the protonated forms are bound more strongly in acidic solution. The complexation-induced chemical shift changes in the guest proton resonances provide an indication of the site(s) of binding and the effects of protonation on the location of the binding sites.
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Affiliation(s)
- Ian W Wyman
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
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17
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Sueishi Y, Asano K, Yamaoka M, Yamamoto S. Characterization of Water-Soluble Cucurbit[7]uril in Alcohol-Water Mixtures by High-Pressure Studies on the Inclusion Complexation with New Methylene Blue. ACTA ACUST UNITED AC 2009. [DOI: 10.1524/zpch.2008.222.1.153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The inclusion complexation of new methylene blue (NMB) with cucurbit[7]uril (CB[7]) was studied spectrophotometrically. It was found that CB[7] forms a 1:1 inclusion complex with NMB in alcohol-water mixtures and the structure of the inclusion complex has been established by 1H-NMR measurements. We have determined the association constants of CB[7] with NMB under high pressures. The association constants of CB[7] increase as the external pressure and solvent polarity increase. Pressure dependence experiments enabled us to calculate the reaction volume for inclusion of CB[7] to range from -15.8 to -10.8cm3 mol-1. From analyses of the high-pressure results, the volume change caused by water and/or alcohol molecules repelled from the CB[7] cavity in the alcohol-water mixtures was evaluated, which is indicative of the presence of water and/or alcohol molecules in the CB[7] cavity in the alcohol-water mixtures. The volume of molecules repelled from the CB[7] cavity plays an important role in the volume change upon inclusion.
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18
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Wang R, MacGillivray BC, Macartney DH. Stabilization of the base-off forms of vitamin B12 and coenzyme B12 by encapsulation of the α-axial 5,6-dimethylbenzimidazole ligand with cucurbit[7]uril. Dalton Trans 2009:3584-9. [DOI: 10.1039/b904028e] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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19
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Wyman IW, Macartney DH. Cucurbit[7]uril host-guest and pseudorotaxane complexes with α,ω-bis(pyridinium)alkane dications. Org Biomol Chem 2009; 7:4045-51. [DOI: 10.1039/b910322h] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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20
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Vincil GA, Urbach AR. Effects of the number and placement of positive charges on viologen–cucurbit[n]uril interactions. Supramol Chem 2008. [DOI: 10.1080/10610270701689572] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
| | - Adam R. Urbach
- a Department of Chemistry , Trinity University , San Antonio, TX, USA
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21
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Zhou Y, Yu H, Zhang L, Sun J, Wu L, Lu Q, Wang L. Host properties of cucurbit [7] uril: fluorescence enhancement of acridine orange. J INCL PHENOM MACRO 2008. [DOI: 10.1007/s10847-008-9414-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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Wyman IW, Macartney DH. Cucurbit[7]uril host–guest complexes with small polar organic guests in aqueous solution. Org Biomol Chem 2008; 6:1796-801. [DOI: 10.1039/b801650j] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Wang R, Macartney DH. Cucurbit[7]uril host–guest complexes of the histamine H2-receptor antagonist ranitidine. Org Biomol Chem 2008; 6:1955-60. [DOI: 10.1039/b801591k] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Wang R, Yuan L, Ihmels H, Macartney DH. Cucurbit[8]uril/Cucurbit[7]uril Controlled Off/On Fluorescence of the Acridizinium and 9-Aminoacridizinium Cations in Aqueous Solution. Chemistry 2007; 13:6468-73. [PMID: 17508370 DOI: 10.1002/chem.200700199] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The blue fluorescence of acridizinium bromide (ADZ+) and the green fluorescence of 9-aminoacridizinium bromide (AADZ+) in aqueous solutions can be almost entirely switched off upon the double inclusion of these guests in the cavity of cucurbit[8]uril (CB[8]) owing to the formation of a nonfluorescent, noncovalent dimer complex, and then fluorescence can be effectively restored by adding cucurbit[7]uril (CB[7]) to the complex because it competitively extracts the fluorophores out of the CB[8] cavity.
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Affiliation(s)
- Ruibing Wang
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, ON K7L 3N6, Canada
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25
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Yuan L, Wang R, Macartney DH. Binding Modes of Cucurbit[6]uril and Cucurbit[7]uril with a Tetracationic Bis(viologen) Guest. J Org Chem 2007; 72:4539-42. [PMID: 17503847 DOI: 10.1021/jo070358e] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Binding behaviors of two cucurbit[n]urils (CB[n]) hosts with the [CH3bpy(CH2)6bpyCH3]4+ (bpy = 4,4'-bipyridinium) guest were investigated by 1H NMR and MALDI-TOF-MS experiments. While the CB[6] and CB[7] form [2]pseudorotaxanes with the host located over the hexamethylene chain of the guest, only the CB[7] forms a [3]pseudorotaxane with both host molecules residing over the bipyridinium groups. The initial CB[7] host vacates the inclusion of the hexamethylene chain as a result of the electrostatic and steric repulsions that would arise in simultaneous binding of adjacent aliphatic and aromatic portions of the guest.
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Affiliation(s)
- Lina Yuan
- Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
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26
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Yuan L, Macartney DH. Kinetics of the Electron Self-Exchange and Electron-Transfer Reactions of the (Trimethylammonio)methylferrocene Host−Guest Complex with Cucurbit[7]uril in Aqueous Solution. J Phys Chem B 2007; 111:6949-54. [PMID: 17407346 DOI: 10.1021/jp0701284] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The electron self-exchange rate constants for the (trimethylammonio)methylferrocene(+/2+) couple (FcTMA+/2+) have been measured in the absence and presence of the cucurbit[7]uril (CB[7]) host molecule in aqueous solution, using 1H NMR line-broadening experiments. The very strong binding of the ferrocene to CB[7] results in slow exchange of the guest on the NMR time scale, such that resonances for both the free and bound forms of the reduced ferrocene can be observed. The extents of line broadening in the resonances of the two forms of the guest in the presence of the FcTMA2+ species can be monitored independently, allowing for the determination of the rate constants for the possible self-exchange pathways involving the bound and free forms of both the oxidized and reduced members of the redox couple. The encapsulation of both the reduced and oxidized forms of the ferrocene increases the rate constant (25 degrees C) from (2.1+/-0.1)x10(6) M-1 s-1 (for FcTMA+/2+) to (6.7+/-0.7)x10(6) M(-1) s(-1) (for {FcTMA.CB[7]}+/2+), whereas inclusion of the reduced form only decreases the rate constant to (6+/-1)x10(5) M(-1) s(-1). The changes in the exchange rate constants upon inclusion of the reactants are related to the effects of CB[7] acting as an outer, second-coordination sphere and are compared to those observed previously for the electron-exchange process in the presence of beta-cyclodextrin and p-sulfonated calix[6]arene hosts. The binding of FcTMA+ and hydroxymethylferrocene to CB[7] significantly reduces the rate constants for their oxidations by the bis(2,6-pyridinedicarboxylato)cobaltate(III) ion (which does not bind to CB[7]) as a result of reduced thermodynamic driving forces and steric hindrance to close approach of the oxidant to the encapsulated ferrocenes.
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Affiliation(s)
- Lina Yuan
- Department of Chemistry, Queen's University, Kingston, ON K7L 3N6, Canada
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Yuan L, Wang R, Macartney DH. Chiroptic behaviour of a chiral guest in an achiral cucurbit[7]uril host. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.02.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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