Encapsulation of Chemotherapeutic Drug Melphalan in Cucurbituril: Effects on Its Alkylating Activity, Hydrolysis, and CytotoxicityGustavo Villarroel-Lecourt, Javiera Carrasco-Carvajal, Felipe Andrade-Villalobos, Fresia Solís-Egaña, Ignacio Merino-San Martín, José Robinson-Duggon & Denis Fuentealba
The formation of inclusion complexes between drugs and macrocycles has proven to be an effective strategy to increase solubilization and stabilization of the drug, while in several cases improving their biological activity. In this context, we explored the formation of an inclusion complex between chemotherapeutic drug Melphalan (Mel) and cucurbituril (CB), and studied its effect on Mel alkylating activity, hydrolysis, and cytotoxicity. The formation of the inclusion complex (Mel@CB) was proven by absorption and fluorescence...
Taking it in turn: Despite the high internal strain, the long aliphatic chains of alkyltrimethylammonium ions buried deeply inside the cucurbituril (CB) cavity adopt a U-shaped conformation (se...
Abstract The ability of three bis-viologen cyclophanes to act as redox-triggered contractile switches is investigated. Odd/even effects in the formation of cyclic bis-viologens are circumvented by ...
Six- and seven-membered cucurbiturils form inclusion complexes with a lutidine derivative. These inclusion complexes differ in the binding mode, stability, kinetics of complexation, and sensitivity toward basic media.
A green to blue fluorescence switch of protonated 2-aminoanthracene upon inclusion in cucurbiturilDonal H. Macartney, Ruibing Wang & Lina Yuan
The inclusion of protonated 2-aminoanthracene in the cavity of cucurbituril increases its pKa values in the ground and excited states, resulting in the disappearance of the green emission of the neutral excited state and the significant enhancement of the blue emissions from the protonated excited state g
Artificial molecular clips and tweezers, designed for cofactor and amino acid recognition, are able to inhibit the enzymatic activity of alcohol dehydrogenase (ADH). IC50 values and kinetic investigations point to two different new mechanisms of interference with the NAD+-dependent oxidoreductase: While the clip seems to pull the cofactor out of its cleft, the tweezer docks onto lysine residues around the active site. Both modes of action can be reverted to some extent, by appropriate additives....
Molecular assemblies of potential guest molecules through non-covalent host–guest interactions have found immense use in many applied areas. In this study supramolecular interaction of a biologically important dye Hoechst-33258 (H33258) has been investigated in aqueous solutions at different pHs, in the pres
Molecular Recognition and Complexation Thermodynamics of Dye Guest Molecules by Modified Cyclodextrins and CalixarenesulfonatesYu Liu, Bao-Hang Han & Yun-Ti Chen
The inclusion complexation behavior of some dye guest molecules with two kinds of molecular receptors, i.e., native α-, β-, and γ-cyclodextrins, and chemically modified β-cyclodextrins, and water-soluble calix[n]arenesulfonates (n = 4, 6, 8) and their lower rim alkylated derivatives, has been investigated. It was found that the fluorescence intensity of guest molecules evidently changes upon the addition of molecular receptors. The calix[n]arenesulfonates (n = 4, 6, 8) cause gradual decreases in the fluorescence intensity, whereas...
The synthesis of rotaxanes, each comprising a viologen core threaded through a cucurbituril (Q8, Figure 1) macrocycle and stoppered by tetraphenylmethane groups, and their binding to second guests as inclusion complexes in organic and aqueous media are described. Stoppering was observed to have little effect on binding. Chemical modification of the threaded guest was used to control solubility and binding characteristics, thus demonstrating a novel approach to making artificial receptors with readily modifiable properties.
Cucurbituril (CB) with a substituent attached solely to one methylene bridge was prepared for the first time. The monosubstituted CB undergoes self-assembly to form a cyclic tetramer in the solid state. The affinity of the monosubstituted CB to a series of alkylammonium salts was measured revealing a minor effect of the substituent on the binding properties of the macrocycle.
Interactions between inverted cucurbituril (iQ) and essential amino acids have been studied at pH = 7.0 by 1H NMR spectroscopy, electronic absorption spectroscopy, isothermal titration calorimetry, and mass spectrometry. The interactions can be divided into three binding types at pH = 7.0. Experimental results from the present study showed that the host displays a strong binding to the aromatic amino acids, Trp and Phe, and the guests of Lys, Arg, and His lie outside the...
A novel calixarene derivative with pyrene fluorophores at the upper rim and tetraester ionophores at the lower rim was synthesized in six steps, and its structure was proved by NMR and ESI-MS spectroscopies. Furthermore, the chemosensing behavior of the host compound for alkali and alkaline earth metal ions was investigated by fluorescence spectroscopy. The obtained results show that the calixarene host can selectively bind sodium ion with the complexation stability constant of 2190 mol−1·L. The...
Study on the inclusion interaction of cucurbit[n]urils with sanguinarine by spectrofluorimetry and its analytical applicationChang-Feng Li, Li-Ming Du & Hui-Ming Zhang
pH-responsive emission behavior of supramolecular complexes between pyridylbutadiene with CB7 and formation of molecular assemblies is described.
Terminal Carboxylate Effects on the Thermodynamics and Kinetics of Cucurbituril Binding to Guests Containing a Central Bis(Pyridinium)-Xylylene SiteIago Neira, Marcos D. Garcia, Carlos Peinador & Angel Kaifer
A series of bis(pyridinium)-xylylene derivatives bearing carboxylate terminal groups were investigated as guests for the cucurbituril host in aqueous solution. While the presence of the terminal carboxylates has a modest effect on the thermodynamic stability of the complexes, the kinetics of complex association/dissociation is strongly affected. The relative position (meta, para) of the carboxylate group in relation to the pyridinium nitrogen also exerts a considerable effect on the binding kinetics.
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.
A spectrophotometric method is used to determine formation constants of complexes ofβ-cyclodextrin, the 2,6-di-O-methylated and 2,3,6-tri-O-methylated derivatives ofβ-cyclodextrin as hosts with adamantan-1-ylammonium, adamantan-2-ylammonium and adamantan-1-ylmethylammonium as substrate species. The spectrophotometric method uses methyl orange anion and acid forms as indicator species. Complexes of the cyclodextrins with these species are determined as well as with the adamantane derivatives. Standard enthalpies and entropies of formation of all complexes are calculated from the temperature variation of the equilibrium...
Supramolecular interaction of cucurbit[n]urils and coptisine by spectrofluorimetry and its analytical applicationChang-Feng Li, Li-Ming Du, Wen-Ying Wu & Ai-Zhuo Sheng
Electrospray ionization mass spectrometry (ESI-MS) is used to probe the binding of small anions to the macrocycle of bambusuril. For the halide ions, the experimental patterns suggest F– < Cl– < Br– < I–, which is consistent with the order of anion binding found in the condensed phase. Parallel equilibrium studies in the condensed phase establish the association constants of halide anions and bambusuril in mixed solvents. A detailed analysis of the mass spectrometric data...
Supramolecular vesicles were successfully constructed on the basis of host–guest complex formation between p-sulfonatocalixarene and 1-pyrenemethylaminium. The obtained vesicles exhibit benign w...
Significant fluorescence enhancement by supramolecular complex formation between berberine chloride and cucurbit(n=7)uril and its analytical applicationZhu Tao, Nan Dong, Li-na Cheng, Xiu-lin Wang, Qin Li & Chuan-yu Dai
Dreifach kontrolliert: TernÃ¤re Komplexe aus einem makrocyclischen Wirt (p-Sulfonatocalixaren), einem organischen Gast (2,3-Diazabicyclo[2.2.2]oct-2-en) und Ãbergangsmetallionen (siehe Bild) result...
The complexation of sulfur hexafluoride (SF6), a highly potent greenhouse gas, by cucurbituril (CB) was studied at various temperatures in Na2SO4 aqueous solutions by 19F and 1H NMR. CB shows a remarkable affinity for SF6, suggesting that it is a suitable molecular container for the design of materials tailored for SF6 trapping. At 298 K, the equilibrium constant characterizing the inclusion of SF6 by CB is 3.1 × 104 M−1 and the residence time of...
Department of Physical and Technical Sciences27
University of Miami17
Institute of Materials and Environmental Chemistry15
Institute of Nanotechnology15
Institute for Basic Science9
Institute of Organic Chemistry8