The binding dynamics of R-(+)-2-naphthyl-1-ethylammonium cation (NpH+) with cucurbituril (CB) was investigated. Competitive binding with Na+ or H3O+ cations enabled the reaction to be slowed down sufficiently for the kinetics to be studied by fluorescence stopped-flow experiments. The binding of two Na+ cations to CB, i.e., CB·Na+ (K01 = 130 ± 10 M–1) and Na+·CB·Na+ (K02 = 21 ± 2 M–1), was derived from the analysis of binding isotherms and the kinetic studies. NpH+ binds...
High Fidelity Kinetic Self-Sorting in Multi-Component Systems Based on Guests with Multiple Binding EpitopesPritam Mukhopadhyay, Peter Y. Zavalij & Lyle Isaacs
The molecular recognition platforms of natural systems often possess multiple binding epitopes, each of which has programmed functional consequences. We report the dynamic behavior of a system comprising CB, CB, and guests cyclohexanediammonium (1) and adamantanealkylammonium (2) that we refer to as a two-faced guest because it contains two distinct binding epitopes. We find that the presence of the two-faced guestjust as is observed for protein targeting in vivodictates the kinetic pathway that the system...
A supramolecular complex between benzoates and a bambusuril crystallizes out immediately after mixing in chloroform but only in the presence of residual water molecules. In this complex each of the two portals of the macrocycle is occupied by one benzoate. Carboxylate groups are connected through hydrogen bo
Abstract Methods for the preparation of anion-free bambusuril (BU6) are presented. They are based on the oxidation of iodide anion, which is bound inside the macrocycle, utilizing dark oxidation...
Distinct photophysical behaviour and transport of cell-impermeable [Ru(bpy)2dppz]2+ in live cells using cucurbituril as a delivery systemMeenakshi Shinde, Soniya Rao, Shridhar Gejji & Anupa Kumbhar
We have successfully demonstrated the delivery of a cell-impermeable [Ru(bpy)2dppz]2+ complex across the cell membrane in live cells using a cucurbituril molecular container.
endo-Functionalized molecular tubes: selective encapsulation of neutral molecules in non-polar mediaGuobao Huang, Arto Valkonen, Kari Rissanen & Wei Jiang
Four endo-functionalized molecular tubes show high binding affinity and selectivity to neutral molecules.
One ring binds them all: A bambusuril macrocycle is able to selectively capture a large number of different inorganic anions in water. The high stability of the resulting inclusion complexes is due t...
A perfect pair: The complex between cucurbituril (CB) and diamantane-4,9-bis(NMe3) (6) has a dissociation constant of 1.4Ã10â18âM in aqueous solution. Competition experiments show that CBâ6 ...
Bambusuril macrocycles allow qualitative and quantitative sensing of anion mixtures in water using 1H NMR spectroscopy.
Supramolecular Storage and Controlled Photorelease of an Oxidizing Agent using a Bambusuril MacrocycleEdoardo Torti, Václav Havel, Mirza A. Yawer, Lucie Ludvíková, Michal Babiak, Petr Klán & Vladimir Sindelar
Abstract The oxidizing ability of peroxodisulfate upon complexation inside the Bambusuril macrocycle cavity is inhibited. This dianionic agent can be released on demand from its stable 1:1 complex ...
Acyclic cucurbit[n]uril-type molecular containers: influence of glycoluril oligomer length on their function as solubilizing agentsLaura Gilberg, Ben Zhang, Peter Y. Zavalij, Vladimir Sindelar & Lyle Isaacs
A series of glycoluril molecular clips and acyclic CB[n]-type receptors are tested as solubilizing agents for insoluble drugs.
Bambusuril macrocycles bind and release sulfide and hydrosulfide anions in water.
Determination of the kinetics underlying the pKa shift for the 2-aminoanthracenium cation binding with cucurbiturilSuma S. Thomas & Cornelia Bohne
The binding dynamics of the 2-aminoanthracenium cation (AH+) and 2-aminoanthracene (A) with cucurbituril (CB) was studied using stopped-flow experiments. The kinetics was followed by measuring the fluorescence changes over time for AH+ and A, which emit at different wavelengths. The studies at various pH values showed different mechanisms for the formation of the AH+@CB complex, with this complex formed either by the binding of AH+ or by the initial binding of A followed by protonation....
Noninnocent Role of Na+ Ions in the Binding of the N-Phenyl-2-naphthylammonium Cation as a Ditopic Guest with CucurbiturilSuma S Thomas, Hao Tang & Cornelia Bohne
Na+ ions influence the mechanism for the binding of the ditopic guest N-phenyl-2-naphthylammonium cation (Ph-AH+-Np) to cucurbituril (CB) by facilitating, at increased Na+ concentrations, the formation of a higher-order complex. Binding of the larger naphthyl moiety of Ph-AH+-Np forms the Ph-AH+-Np@CB 1:1 complex (where “@” represents an inclusion complex) at low Na+ ion concentrations (≤5 mM), whereas the inclusion of the smaller phenyl moiety in CB (CB@Ph-AH+-Np) is transient. Ph-AH+-Np@CB is formed by reactions with...
Selective Recognition of Highly Hydrophilic Molecules in Water by Endo-Functionalized Molecular TubesGuo-Bao Huang, Sheng-Hua Wang, Hua Ke, Liu-Pan Yang & Wei Jiang
Selective recognition of neutral hydrophilic molecules in water is a challenge for supramolecular chemistry but commonplace in nature. By mimicking the binding pocket of natural receptors, endo-functionalized molecular tubes are proposed to meet this challenge. We found that two molecular tubes with inwardly directed hydrogen-bond donors recognize highly hydrophilic solvent molecules in water with high selectivity. In the complexes, hydrogen bonding occurs in the deep and hydrophobic cavity. The cooperative action between hydrogen bonding and...
(2014). Supramolecular control of phthalocyanine dye aggregation. Supramolecular Chemistry: Vol. 26, Cucurbit[n]uril: Molecular Barrels of Opportunity (ICCB 2013), pp. 642-647.
We determined the values of Ka for a wide range of host−guest complexes of cucurbit[n]uril (CB[n]), where n = 6−8, using 1H NMR competition experiments referenced to absolute binding constants measured by UV/vis titration. We find that the larger homologuesCB and CBindividually maintain the size, shape, and functional group selectivity that typifies the recognition behavior of CB. The cavity of CB is found to effectively host trimethylsilyl groups. Remarkably, the values of Ka for the...
Abstract Bambusurils are a class of neutral anion receptors with outstanding binding properties in various solvents. The host–guest associations of bambusurils in aqueous environments have been ...
pH-responsive emission behavior of supramolecular complexes between pyridylbutadiene with CB7 and formation of molecular assemblies is described.
Bambusuril as a One-Electron Donor for Photoinduced Electron Transfer to Methyl Viologen in Mixed CrystalsVladimir Sindelar, Lucie Ludvíková, Michal Babiak, Petr Klán, Dominik Heger, Tomas Fiala, Jan Švec, Tomáš Slanina, L’ubica Vetráková, Marek Nečas & Petr Kulhánek
Methyl viologen hexafluorophosphate (MV2+·2PF6–) and dodecamethylbambusuril (BU6) form crystals in which the layers of viologen dications alternate with those of a 1:2 supramolecular complex of BU6 and PF6–. This arrangement allows for a one-electron reduction of MV2+ ions upon UV irradiation to form MV+• radical cations within the crystal structure with half-lives of several hours in air. The mechanism of this photoinduced electron transfer in the solid state and the origin of the long-lived charge-separated...
Cyclodextrin-assisted modulation of the photophysical properties and acidity constant of pyrene-armed calixareneV. S. Kalyani, D. D. Malkhede & Jyotirmayee Mohanty
The supramolecular pKa shift and modulation in the monomer and excimer emission behaviour of pyrene-armed calixarene with cyclodextrins find applications in ratiometric sensing.
The interlocked bambusuril: Reactive hypervalent iodine species possessing dynamic covalent bonds are utilized in a constitutive sense for the near quantitative synthesis of rotaxanes via the stabili...
Cucurbituril inclusion complexation as a supramolecular strategy for color stabilization of anthocyanin model compoundsBarbara Held, Hao Tang, Palani Natarajan, Cassio Pacheco da Silva, Volnir de Oliveira Silva, Cornelia Bohne & Frank H. Quina
Complete stabilization of the color of a flavylium cation by the formation of a higher order (1 : 2) complex with cucurbituril.
Two bis-urea macrocycles with a deep cavity demonstrate an enzyme-like binding, and the influence of dipole alignments on molecular recognition.
Science still does not have the ability to accurately predict changes in ligand affinity induced by proximal charged groups.
Department of Physical and Technical Sciences27
Central European Institute of Technology3
Homi Bhabha National Institute2
University of Miami2
University of Maryland, College Park2
University of Victoria2
Institute for Basic Science1
Biomolecular Research Genomics (Italy)1
Instituto de Química Médica1