Controlling Factors in the Synthesis of Cucurbituril and Its Homologues

Day, Anthony I.; Arnold, Alan P.; Blanch, Rodney J.; Snushall, Barry B

doi:10.1021/jo015897c

Cited by 969 publications

(1,212 citation statements)

References 23 publications

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“…Q [9] or Q [10]. 40 Similar reductions in the distances between Pt-Pt centres were also found for the tri-Pt complexes. Q [7] was shown to encapsulate the hydrolysed form of di-Pt, and based upon the similarity of the chemical shifts of the bound metal complex, it can be concluded that the cucurbituril was positioned in a similar fashion to the Cl form of di-Pt.…”

Section: Discussionsupporting

confidence: 61%

Cucurbit[n]uril binding of platinum anticancer complexes

et al. 2006

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The encapsulation of cisplatin by cucurbit [7]uril (Q[7]) and multinuclear platinum complexes linked via a 4,4 -dipyrazolylmethane (dpzm) ligand by Q [7] and cucurbit [8] 4+ (tri-Pt) provide a barrier to the on and off movement of cucurbituril, resulting in binding kinetics that are slow on the NMR timescale for the metal complex. Although the dpzm ligand has relatively few rotamers, encapsulation by the larger Q[8] resulted in a more compact di-Pt conformation with each platinum centre retracted further into each Q[8] portal. Encapsulation of the hydrolysed forms of di-Pt and tri-Pt is considerably slower than for the corresponding Cl forms, presumably due to the high-energy cost of passing the +2 platinum centres through the cucurbituril portals. The results of this study suggest that cucurbiturils could be suitable hosts for the pharmacological delivery of multinuclear platinum complexes.

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Section: Discussionsupporting

confidence: 61%

Cucurbit[n]uril binding of platinum anticancer complexes

et al. 2006

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“…Cucurbit [7]uril (CB7) was synthesized according to the literature. [76][77][78] Acridine orange (AO), thermolysin (lyophilized powder, 36.5 U/mg) and phosphoramidon were used as received from Sigma-Aldrich.…”

Section: Exo-and Endopeptidase Behaviormentioning

confidence: 99%

Determining Protease Substrate Selectivity and Inhibition by Label-Free Supramolecular Tandem Enzyme Assays

et al. 2011

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An analytical method has been developed for the continuous monitoring of protease activity on unlabelled peptides in real time by fluorescence spectroscopy. The assay is enabled by a reporter pair comprising the macrocycle cucurbit [7]uril (CB7) and the fluorescent dye acridine orange (AO). CB7 functions by selectively recognizing N-terminal phenylalanine residues as they are produced during the enzymatic cleavage of enkephalintype peptides by the metalloendopeptidase thermolysin. The substrate peptides (e.g., ThrGly-Ala-Phe-Met-NH2) bind to CB7 with moderately high affinity (K ca. 10 4 M -1 ), while their cleavage products (e.g., Phe-Met-NH2) bind very tightly (K > 10 6 M -1 ). AO signals the reaction upon its selective displacement from the macrocycle by the high affinity product of proteolysis. The resulting supramolecular tandem enzyme assay effectively measures the kinetics of thermolysin, including the accurate determination of sequence specificity (Ser and Gly instead of Ala), stereospecificity (DAla instead of LAla), endo-versus exopeptidase activity (indicated by differences in absolute fluorescence response), and sensitivity to terminal charges (-CONH2 versus -COOH). The capability of the tandem assay to measure protease inhibition constants was demonstrated on phosphoramidon as a known inhibitor to afford an inhibition constant of (17.8 ± 0.4) nM. This robust and label-free approach to the study of protease activity and inhibition should be transferable to other endo-and exopeptidases that afford products with N-terminal aromatic amino acids.2

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“…21,[30][31][32][33][34][35][36][37][38][39][40][41][42][43] The pioneering work of Lehn, Cram, and Pedersen brought host-guest and supramolecular chemistry to the forefront of contemporary science. [44][45][46] The scientific insights gained from fundamental studies of non-covalent interactions have been of practical value in a wide range of applications including chromatographic stationary phases, sequestration of contaminants from solution, and the development of catalysts, chemical sensors, and new drugs.…”

Section: List Of Figuresmentioning

confidence: 99%

Cucurbit[n]uril Analogues

2003

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Molecular recognition and self-assembly in aqueous solution have experienced rapid growth in recent years. The use of -, -, and -cyclodextrins, calixarenes, and cyclophanes have served as the platforms for molecular recognition in aqueous solution. Recently, the investigation of an alternative platform based on cucurbituril has become the focus of several research groups. The rigid structure and capability of forming complexes with molecules and ions through hydrophobic, iondipole and hydrogen-bonding interactions make cucurbituril an attractive candidate as a synthetic receptor as well as a building block for the construction of supramolecular architectures.However, before cucurbituril can be used to supplant the more common platforms as the molecule of choice for molecular recognition and self-assembly in aqueous solution, several advances must be made: 1) cucurbiturils must become available in a variety of sizes, 2) their solubility must be improved, and 3) synthetic procedures must be advanced to include the ability to selectively generate specific cucurbituril homologues, derivatives, and analogues. To help rationalize the high yields obtained in these macrocyclization reactions, we performed mechanistic studies of model methylene bridged glycoluril dimers.The molecular recognition properties of a water soluble cucurbit[6]uril analogue in aqueous buffer toward a variety of guests including alkanediamines, aromatics, amino acids, and nucleobases were studied by fluorescence spectroscopy.For the alkanediamines studied, as the length of the alkane is increased between the amines, the association constants also increase. The CB [6] analogue is capable of forming strong complexes with guests containing aromatic rings with association constants (K a ) ranging from 10 2 to 10 6 M -1 due to the favorable -interactions that occur between the host and the aromatic portion of the guest while encapsulated in its hydrophobic cavity. CUCURBIT[N]URIL ANALOGUES

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Controlling Factors in the Synthesis of Cucurbituril and Its Homologues

Cited by 969 publications

References 23 publications

Cucurbit[n]uril binding of platinum anticancer complexes

Cucurbit[n]uril binding of platinum anticancer complexes

Determining Protease Substrate Selectivity and Inhibition by Label-Free Supramolecular Tandem Enzyme Assays

Cucurbit[n]uril Analogues

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