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Host-stabilized charge-transfer (CT) interactions and supramolecular assemblies built with these interactions are described. A variety of supramolecular assemblies including polyrotaxanes, molecular necklaces, and rotaxane dendrimers were synthesized through the intramolecular or intermolecular host-stabilized CT complex formation using cucurbit[8]uril (CB[8]) and D-A molecules having both electron-donor and electron-acceptor units connected by various types of linkers. Applications, including t

Without modification of its periphery, cucurbit[7]uril (a macrocyclic cavitand comprising seven glycoluril units) forms a hydrogel. The gelation is thermoreversible and sensitive to pH, but is inhibited by the presence of alkali-metal ions and shows guest-induced stimuli-responsive behavior: upon addition of a small amount of a guest, it undergoes a reversible gel–sol transition with alternating UV irradiation and heat treatment (see picture).

Under lock and key: A molecular machine based on the redox-coupled guest exchange of a cucurbit[8]uril-stabilized charge-transfer complex is reported. It behaves as a molecular loop lock that requires not only a key but also an activation process to open (see graphic).

The design and synthesis of two-dimensional (2D) polymers is a challenging task, hitherto achieved in solution only through the aid of a solid surface "template" or preorganization of the building blocks in a 2D confined space. We present a novel approach for synthesizing free-standing, covalently bonded, single-monomer-thick 2D polymers in solution without any preorganization of building blocks on solid surfaces or interfaces by employing shape-directed covalent self-assembly of rigid, disk-sha

A novel noncovalent method to immobilize a protein on a solid surface using the cucurbit[7]uril (CB[7])-ferrocenemethylammonium ion (FA) pair, which exhibits exceptionally high binding affinity ( K ≈ 10 12 M -1 ), is reported. This method involves (1) anchoring CB[7] units on an alkanethiolate self-assembled monolayer (SAM) on gold, (2) attachment of FA units to a protein to be immobilized, and (3) immobilization of the “ferrocenylated” protein to the CB[7]-attached SAM on gold. As a proof of co

Over the past decades, numerous efforts have been devoted to synthesizing nanostructured materials with specific morphology because their size and shape play an important role in determining their functions. Self-assembly using weak and reversible interactions or bonds has provided synthetic routes toward various nanostructures because it allows a "self-checking" and "self-error-correcting" process under thermodynamic control. By contrast, the use of irreversible covalent bonds, despite the pote

A facile synthesis of highly stable, water-dispersible metal-nanoparticle-decorated polymer nanocapsules (M@CB-PNs: M=Pd, Au, and Pt) was achieved by a simple two-step process employing a polymer nanocapsule (CB-PN) made of cucurbit[6]uril (CB[6]) and metal salts. The CB-PN serves as a versatile platform where various metal nanoparticles with a controlled size can be introduced on the surface and stabilized to prepare new water-dispersible nanostructures useful for many applications. The Pd nano

Biosensors based on a field‐effect transistor platform allow continuous monitoring of biologically active species with high sensitivity due to the amplification capability of detected signals. To date, a large number of sensors for biogenic substances have used high‐cost enzyme immobilization methods. Here, highly sensitive organic field‐effect transistor (OFET)‐based sensors functionalized with synthetic receptors are reported that can selectively detect acetylcholine (ACh + ), a critical ion r

A novel three-way supramolecular switch based on the interconversion of hetero-guest-pair (D-A) and homo-guest-pair (D(2) or A(2)) inclusion inside cucurbit[8]uril is reported, which can be selectively controlled by chemical or electrochemical stimuli.

Hinter Schloss und Riegel: Eine molekulare Maschine, die auf dem redoxgekoppelten Gastaustausch eines Cucurbit[8]uril-stabilisierten Charge-Transfer-Komplexes basiert, wird vorgestellt. Sie verhält sich wie ein molekulares Kettenschloss, für dessen Öffnen nicht nur ein Schlüssel, sondern auch ein Aktivierungsschritt benötigt wird (siehe Bild). Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2001/2005/z461806_s.pdf or from the author. Plea

Abstract This review describes monovalent synthetic receptor–ligand (or host–guest) pairs with extremely high binding affinity, comparable to that of the biotin–avidin pair, and their applications. Cucurbit[7]uril (CB[7]), a member of the host family cucurbit[ n ]uril (CB[ n ], n =5–8, 10), forms ultrastable host–guest complexes with ferrocene‐, adamantane‐ or bicyclo[2.2.2]octane‐based molecules having ammonium groups properly positioned to interact with the carbonyl oxygens at the portals of C

An der Peripherie nicht modifiziertes Cucurbit[7]uril, ein makrocyclischer Cavitand aus sieben Glycoluril-Einheiten, bildet ein Hydrogel. Diese Gelierung ist thermisch reversibel und pH-empfindlich und wird durch Alkalimetallionen verhindert. Die Zugabe einer geringen Gastmenge resultiert in einem stimulierbaren Gel-Sol-Übergang, der durch abwechselndes UV-Bestrahlen und Erwärmen reversibel ist (siehe Bild).

We have designed and synthesized a novel [2]pseudorotaxane-based molecular machine in which the interconversion between end-to-interior and end-to-end loop structures is reversibly controlled by electrochemical stimuli. Cucurbit[8]uril (CB[8]) and the thread molecule 3(4+) with an electron-rich hydroxynaphthalene unit and two electron-deficient viologen units form the 1:1 complex 4(4+) with an end-to-interior loop structure, which is reversibly converted into an end-to-end structure upon reducti