Guest Encapsulation within Self‐Assembled Molecular Containers

Abstract

Molecular hospitality: Self‐assembled molecular containers provide a very specific geometric as well as chemical environment for a bound guest, which allows for selective guest binding or the stabilization of unstable molecules or unstable conformations within the capsule (see scheme). The geometric constraints imposed by the container can even change the outcome of a chemical reaction.

Aza Cope Rearrangement of Propargyl Enammonium Cations Catalyzed By a Self-Assembled “Nanozyme”

“…To emulate this mode of catalysis, many research groups have designed synthetic hosts capable of binding and directing the reactivity of guest molecules. [5][6][7][8][9][10][11][12][13] Upon encapsulation in either a synthetic host or an enzyme active site, the environment surrounding a guest molecule drastically differs from that of the bulk solution. Steric constraints, functional group positioning, and sequestration from other molecules can enforce reactivity and selectivity that is impossible when simpler catalysts are employed.…”

“…This synthetic strategy provides access to complex structures in far fewer steps than traditional synthetic strategies, and has thus become a popular method for preparing large host assemblies. 10,12,17,18 Raymond and coworkers have developed a series of self-assembled supramolecular metal-ligand assemblies of M 4 L 6 stoichiometry (M = Ga 3+ (1), Al 3+ , Fe 3+ ; L = N,N′-bis (2,3-dihydroxybenzoyl)-1,5-diaminonaphthalene). [19][20][21][22] The four trivalent metal atoms are located at the vertices of the tetrahedron, while naphthalene-based bis-bidentate catechol ligands span the edges, forming a T-symmetric, cavitycontaining assembly (Figure 1).…”

Spin Equilibria in Monomeric Manganocenes: Solid-State Magnetic and EXAFS Studies

“…While the development of synthetic host-guest systems has not reached the level of enzyme specificity, the characteristics of each synthetic assembly, such as the size, shape, charge, and functional group availability, greatly influence the guest-binding characteristics and have led to remarkable and often unexpected reactivity. 9,[16][17][18][19][20][21][22][23] For example, the increased local concentration upon encapsulation of substrates for bimolecular reactions has been exploited for enhanced reactivity inside of synthetic hosts. By pre-organizing substrates, supramolecular assemblies are able to catalyze cycloadditions or pericyclic reactions such as Diels-Alder reactions.…”

The Acid Hydrolysis Mechanism of Acetals Catalyzed by a Supramolecular Assembly in Basic Solution

“…[1][2][3][4][5] While stoichiometric reactivity has produced remarkable examples of both enhanced selectivity and changes in reactivity, [6][7][8][9][10][11][12][13][14] product inhibition has often prohibited catalytic turnover. 7,12,15 In order to abate this problem, a number of strategies including changing the substrate or relying on further reactivity of the product following escape from the cavity, have been employed in order prevent re-encapsulation of the product.…”