We determined the values of Ka for a wide range host−guest complexes cucurbit[n]uril (CB[n]), where n = 6−8, using 1H NMR competition experiments referenced to absolute binding constants measured by UV/vis titration. find that larger homologuesCB[7] and CB[8]individually maintain size, shape, functional group selectivity typifies recognition behavior CB[6]. The cavity CB[7] is found effectively host trimethylsilyl groups. Remarkably, interaction with adamantane derivatives 22−24 exceeds 1012...

This paper describes the immobilization of ten proteins and two low-molecular-weight ligands on mixed self-assembled monolayers (SAMs) alkanethiolates gold generated from tri(ethylene glycol)-terminated thiol 1 (HS(CH2)11(OCH2CH2)3OH) (chi(1) = 1.0-0.0) longer, carboxylic acid-terminated thiol2(HS(CH2)11(OCH2-CH2)6OCH2CO2H) (chi(2) 0.0-1.0). The was achieved by a two-step procedure: generation reactive N-hydroxysuccinimidyl esters acid groups 2 in SAM coupling these with amines protein or...

The molecular host cucurbit[7]uril forms an extremely stable inclusion complex with the dicationic ferrocene derivative bis(trimethylammoniomethyl)ferrocene in aqueous solution. equilibrium association constant for this host-guest pair is 3 x 10(15) M(-1) (K(d) = 10(-16) M), equivalent to that exhibited by avidin-biotin pair. Although purely synthetic systems larger constants have been reported, present one unique because it does not rely on polyvalency. Instead, achieves its extreme...

Conspectus This Account focuses on stimuli responsive systems that function in aqueous solution using examples drawn from the work of Isaacs group cucurbit[n]uril (CB[n]) molecular containers as key recognition elements. Our entry into area began with preparation glycoluril derived clips efficiently distinguish between self and nonself by H-bonds π-π interactions even within complex mixtures therefore undergo self-sorting. We concluded selectivity a wide variety H-bonded supramolecular...

In this paper, we pose the question of whether self-sorting in designed systems is exceptional behavior or it likely to become a more general phenomenon governing molecular recognition and self-assembly. To address prepared mixture comprising two Davis' self-assembled ionophores, Rebek's tennis ball calixarene tetraurea capsule, Meijer's ureidopyrimidinone, Reinhoudt's bis(rosette), clips CDCl3 solution observed ensemble by 1H NMR. As hypothesized, high-fidelity was observed. The influence...

This feature article details some of the unusual recognition properties cucurbit[n]uril family (CB[n]) molecular containers. It discusses mechanism CB[n] formation, which proceeds from glycoluril via methylene bridged oligomers, along with descriptions structures and kinetically stable macrocyclic intermediates way. These partially formed CB[n]-type receptors known as nor-seco-CB[n] display intriguing such chiral recognition, homotropic allostery, function aldehyde reaction cucurbituril synthons.

Abstract Im Jahre 1981 tauften Mock und Mitarbeiter das makrocyclische methylenverbrückte Glycoluril‐Hexamer (CB[6]) auf den Namen “Cucurbituril” – da ihre Form einem Kürbis ähnelt, dem bekanntesten Mitglied der Cucurbitaceae‐Familie in Pflanzenwelt. In folgenden Jahren wurden die grundlegenden Bindungseigenschaften von CB[6] hohe Affinität Selektivität sowie Einschluss Gästen bahnbrechenden Arbeiten Gruppen Mock, Kim Buschmann aufgezeigt; es folgten Anwendungen Wasseraufarbeitung,...

Abstract Host⋅guest complexes between cucurbit[7] (CB[7]) or CB[8] and diamantane diammonium ion guests 3 6 were studied by 1 H NMR spectroscopy X‐ray crystallography. competition experiments revealed that CB[7]⋅ is among the tightest monovalent non‐covalent ever reported in water with K a =7.2×10 17 M −1 pure D 2 O 1.9×10 15 buffered NaO CCD (50 m ). The crystal structure of allowed us to identify some structural features responsible for ultratight binding, including distance NMe + groups...

The covalent modification of therapeutic biomolecules has been broadly explored, leading to a number clinically approved modified protein drugs. These modifications are typically intended address challenges arising in biopharmaceutical practice by promoting improved stability and shelf life proteins formulation, or modifying pharmacokinetics the body. Toward these objectives, with poly(ethylene glycol) (PEG) common direction. Here, platform approach is described that relies on noncovalent,...

Two kinds of shape-controllable and fluorescent supramolecular organic frameworks (cuboid or spheroid) are constructed hierarchically from CB[8] tetraphenylethylene derivatives through host-guest interaction in water. These two SOFs exhibit intriguing varied photophysical properties, including large red-shifts (up to 82 nm) stimuli-responsive behavior competitive guest by binding with CB[8], the turn-on fluorescence which is applied cellular imaging.

Self-assembly of ligand 1 and Pd(NO3)2 delivers Fujita-type metal-organic polyhedron (MOP) 3 which bears 24 covalently attached methyl viologen units on its external surface, as evidenced by 1H NMR, diffusion-ordered spectroscopy electrospray mass spectrometry, transmission electron microscopy, atomic force microscopy measurements. MOP undergoes noncovalent complexation with cucurbit[n]urils to yield MOPs 4-6 diameter ≈5-6 nm. 5 can be fully loaded doxorubicin (DOX) prodrug 2 via...

Tris(vancomycin carboxamide) binds a trivalent ligand derived from d -Ala- -Ala with very high affinity: dissociation constant ( K ) ≈ 4 × 10 –17 ± 1 M. High-affinity binding and monovalent are fundamentally different. In (and more generally, polyvalent) binding, occurs in stages, its rate can be accelerated by at sufficiently concentrations. is determined solely the for cannot added monomer. Calorimetric measurements system indicate an approximately additive gain enthalpy relative to...

Abstract A rapid and inexpensive method for the large‐scale purification of C 60 is simple filtration toluenesoluble extract commercial fullerene soot through a short plug charcoal/silica gel with toluene as eluent. Reactions ethyl tert ‐butyl diazoacetates in refluxing lead to formation (alkoxycarbonyl)methylene‐bridged isomers 1a – 3a 1b 3b , respectively, which can be equilibrated, upon further heating, into single compounds respectively. Isomers / b possess methano bridge at 6–6 ring...

Melamine diamine 1 is able to displace CB[5] from the CB[10].CB[5] complex resulting in CB[10].12 and precipitated CB[5].1. We were isolate free CB[10] by treatment of CB[10].1 with acetic anhydride followed washing MeOH, DMSO, water. The spacious cavity large guests, including a cationic calix[4]arene derivative its 1,3-alternate form (CB[10].1,3-alt-3). addition adamantane carboxylic acid (4) CB[10].3 triggers conformational change during formation termolecular CB[10].cone-3.4.

Many drug delivery systems are based on the ability of certain macrocyclic compounds - such as cyclodextrins (CDs) to act molecular containers for pharmaceutical agents in water. Indeed beta-CD and its derivatives have been widely used formulation hydrophobic pharmaceuticals despite their poor abilities a container (e.g., weak binding (K(a)<10(4) M(-1)) challenges toward chemical functionalization. Cucurbit[n]urils (CB[n]) class that bind variety cationic neutral species with high affinity...

An overall yield of 35% based on C60 was obtained in the synthesis hexaadduct 1. First, bis- and trisadducts were prepared regiospecifically by tether-directed remote functionalization. Further functionalization trisadduct via a single tetraadduct gave pseudooctahedral 1 regiospecifically. All intermediates isolated pure form without use tedious, scale-limiting HPLC methods.

We present a building-block approach toward functionalized CB[7] derivatives by the condensation of methylene-bridged glycoluril hexamer 1 and bis(cyclic ethers) 2 12. The Me2CB[7] CyCB[7] are highly soluble in water (264 mM 181 mM, respectively). As result high intrinsic solubility Me2CB[7], it is able to solubilize insoluble benzimidazole drug albendazole. reaction with derivative 12, which bears primary alkyl chloride group, gives 18 16% isolated yield. Compound reacts NaN3 yield...

The molecular recognition platforms of natural systems often possess multiple binding epitopes, each which has programmed functional consequences. We report the dynamic behavior a system comprising CB[6], CB[7], and guests cyclohexanediammonium (1) adamantanealkylammonium (2) that we refer to as two-faced guest because it contains two distinct epitopes. find presence guestjust is observed for protein targeting in vivodictates kinetic pathway follows toward equilibrium. influence structure,...

Mesoporous silica nanoparticles (MSNs) are promising solid supports for controlled anticancer drug delivery. Herein, we report biocompatible layer-by-layer (LbL) coated MSNs (LbL-MSNs) that designed and crafted to release encapsulated drugs, e.g., doxorubicin hydrochloride (DOX), by changing the pH or adding competitive agents. The LbL coating process comprises bis-aminated poly(glycerol methacrylate)s (BA-PGOHMAs) cucurbit[7]uril (CB[7]), where CB[7] serves as a molecular bridge holding two...

Self-sortingthe ability to efficiently distinguish between self and nonselfis common in nature but is still relatively rare synthetic supramolecular systems. We report a 12-component mixture comprising 1−11 KCl that undergoes thermodynamically controlled self-sorting aqueous solution based on metal−ligand, ion−dipole, electrostatic, charge-transfer interactions, as well the hydrophobic effect. refer this molecular ensemblecharacterized by high-fidelity hostguest interactions componentsas...