Inclusion complexes of coumarin in cucurbiturils.
21 May 2009-Organic and Biomolecular Chemistry (The Royal Society of Chemistry)-Vol. 7, Iss: 11, pp 2435-2439
TL;DR: Coumarin was found to form stable inclusion complexes with cucurbiturils, and a solid phase 1 : 2 host : guest complex was found in a single crystal X-ray diffraction structure determination.
Abstract: Coumarin was found to form stable inclusion complexes with cucurbiturils. In the presence of cucurbit[7]uril (CB[7]), 1 : 1 inclusion complexes were observed in aqueous solution, as monitored by 1H NMR and UV-visible absorption spectroscopies, and further supported by ab initio calculations, whereas with cucurbit[8]uril (CB[8]) a solid phase 1 : 2 host : guest complex was found in a single crystal X-ray diffraction structure determination.
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1,254 citations
TL;DR: Cucurbit[n]urils have become key units in various self-organizing and stimulus-controlled assemblies, as well as in advanced materials and drug carriers.
Abstract: This review highlights the past six year advances in the blossoming field of cucurbit[n]uril chemistry. Because of their exceptional recognition properties in aqueous medium, these pumpkin-shaped macrocycles have been generating some tremendous interest in the supramolecular community. They have also become key units in various self-organizing and stimulus-controlled assemblies, as well as in advanced materials and drug carriers. The scope of this review is limited to the main family of cucurbit[n]urils (n = 5, 6, 7, 8, 10). The reader will find an overview of their preparation, their physicochemical and biological properties, as well as their recognition abilities towards various organic and inorganic guests. Detailed thermodynamic and kinetic considerations, as well as multiple applications including supramolecular catalysis are also discussed.
792 citations
TL;DR: The potential use of cucurbiturils in drug delivery in the context of getting a new drug into clinical trials is examined and what further research is needed in this area is discussed.
Abstract: In this paper we review cucurbit[n]urils (CB[n]), a relatively new family of macrocycles that has shown potential in improving drug delivery. Encapsulation of drugs within the homologues CB[6], CB[7], or CB[8] can impart enhanced chemical and physical stability, improve drug solubility, and control drug release. The formulation of CB[n] into a dosage form suitable for clinical use is a non-trivial task, because the free macrocycle and its host-drug complex generally exhibit pseudo-polymorphism in the solid state. Despite this, cucurbiturils have been included in tablets for oral delivery and inserts for nasal delivery. Here we examine the potential use of cucurbiturils in drug delivery in the context of getting a new drug into clinical trials and discuss what further research is needed in this area.
237 citations
TL;DR: In this article, a self-closing effect was rationalized in terms of multiple weak CH···O interactions between the macrocycles, the degree of which is discussed in detail.
Abstract: Cucurbit[n]urils (CB[n], n = 5–8) have been prepared, separated, and purified, and the structure of their solid state assemblies has been addressed. A number of general features were identified which are of interest to understand some peculiar properties of cucurbiturils (solubility, aggregation, assembly, transformation to porous crystals, influence of air humidity). CB[5], CB[6], and CB[8] were isolated as hydrate crystals whose structures were found to show a strong tendency of the macrocycles to interpenetrate. A self-closing effect was rationalized in terms of multiple weak CH···O interactions between the macrocycles, the degree of which is discussed in detail. Solid state cross polarization magic angle spinning (CP-MAS) 13C NMR spectra obtained at 900 MHz were correlated with the crystal structures. An odd–even effect in the crystallinity of thermally treated CB samples (CB[5] and CB[7] amorphous, CB[6] and CB[8] crystalline) was observed, which is reflected in differences in water solubility (CB[5]...
137 citations
TL;DR: This review summarizes the host-guest complexation of biologically important molecules with CBn, and highlights their implementation in medicinal chemistry and chemical biology.
Abstract: The supramolecular chemistry of cucurbit[n]urils (CBn) has been rapidly developing to encompass diverse medicinal applications, including drug formulation and delivery, controlled drug release, and sensing for bioanalytical purposes. This is made possible by their unique recognition properties and very low cytotoxicity. In this review, we summarize the host-guest complexation of biologically important molecules with CBn, and highlight their implementation in medicinal chemistry and chemical biology.
103 citations
Cites background from "Inclusion complexes of coumarin in ..."
...Crystal structures revealed the encapsulation of two coumarin units inside CB8 (Wang et al., 2009)....
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...Coumarin, an anti-coagulent, was found to form stable inclusion complexes with CB7 and CB8 in aqueous solution (Wang et al., 2009)....
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References
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TL;DR: In 1981, the macrocyclic methylene-bridged glycoluril hexamer (CB[6]) was dubbed "cucurbituril" by Mock and co-workers because of its resemblance to the most prominent member of the cucurbitaceae family of plants--the pumpkin.
Abstract: In 1981, the macrocyclic methylene-bridged glycoluril hexamer (CB[6]) was dubbed "cucurbituril" by Mock and co-workers because of its resemblance to the most prominent member of the cucurbitaceae family of plants--the pumpkin. In the intervening years, the fundamental binding properties of CB[6]-high affinity, highly selective, and constrictive binding interactions--have been delineated by the pioneering work of the research groups of Mock, Kim, and Buschmann, and has led to their applications in waste-water remediation, as artificial enzymes, and as molecular switches. More recently, the cucurbit[n]uril family has grown to include homologues (CB[5]-CB[10]), derivatives, congeners, and analogues whose sizes span and exceed the range available with the alpha-, beta-, and gamma-cyclodextrins. Their shapes, solubility, and chemical functionality may now be tailored by synthetic chemistry to play a central role in molecular recognition, self-assembly, and nanotechnology. This Review focuses on the synthesis, recognition properties, and applications of these unique macrocycles.
2,074 citations
2,057 citations
TL;DR: This Account is a compilation of recent literature covering the syntheses of the homologues and derivatives, and their supramolecular chemistry of cucurbituril, a synthetic receptor.
Abstract: The supramolecular chemistry of cucurbituril, a synthetic receptor, is fascinating because of the remarkable guest binding behavior of the host. Studies in the field, however, have met with limitations, since the only species known was the hexameric macrocyclic compound, cucurbit[6]uril. Recently we synthesized its homologues, cucurbit[n]uril (n = 5, 7, 8), and derivatives. These new members of the cucurbituril family have expanded the scope further, and interest in them has grown enormously. This Account is a compilation of recent literature covering the syntheses of the homologues and derivatives, and their supramolecular chemistry.
1,544 citations
1,008 citations