Molecular Recognition with Resorcin[4]arene Cavitands: Switching, Halogen-Bonded Capsules, and Enantioselective Complexation

Abstract

The development of synthetic host-guest chemistry to investigate and quantify weak, non-covalent interactions has been key to unraveling the complexity of molecular recognition in chemical and biological systems. Macrocycles have shown great utility in the design of receptors, enabling the development of highly preorganized structures. Among macrocycles, resorcin[4]arene-based cavitands have become privileged scaffolds due to their synthetic tunability, which allows access to structures with precisely defined geometries, as well as receptors that display conformational switching between two distinct states with a large difference in guest-binding properties. Here, we highlight three case studies demonstrating redox- and photoredox-controlled switching of molecular recognition properties, the formation of guest-binding supramolecular capsules based solely on halogen-bonding interactions, and enantioselective encapsulation of chiral, substituted cyclohexanes by enantiopure cage compounds as a result of perfect shape complementarity, dispersion interactions, and halogen bonding. The high geometrical and conformational control that can be achieved with resorcin[4]arene-derived host systems will continue to be a powerful resource in future molecular recognition studies.

Computational NMR Spectra of o‐Benzyne and Stable Guests and Their Hemicarceplexes

“…[12] Hemicarcerands and otherc lasses of molecular containers can be used for many different applications in molecular recognition, catalysis, drug delivery,and storage. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] For instance, Cram and co-workerss ynthesized the highly reactivec yclobutadiene insideahemicarcerand, [30] and investigated the binding properties of hemicarcerands that can undergo chemical reactionsw ithoutg uest-release. [31] In the literature, other examples have been given of unstablec ompounds that exhibita high stabilityw hen encapsulatedi nside host molecules.…”

Vase‐Kite Equilibrium of Resorcin[4]arene Cavitands Investigated Using Molecular Dynamics Simulations with Ball‐and‐Stick Local Elevation Umbrella Sampling

“…[34] During the last decades, resorcin [4]arenes involving many different functionalizations have been synthesized and investigated. [35][36][37] These functionalizations mainly aimed at tuning properties such as the solubility in various solvents, [6][10] [38][39][40] the guest-binding capabilities, [10] [34][37] [41][42][43][44][45][46] the position of the equilibrium between the VASE and KITE forms, [11] [47 -49] and its control by means of external stimuli. [11] [16] [17] [36] [49 -60] For a given resorcin [4]arene, the VASE-KITE equilibrium is influenced by environmental factors including temperature, [1] solvent size and polarity, [61] proton concentration [62] (pH), and ion concentration.…”

The Quest for Molecular Grippers: Photo‐Electric Control of Molecular Gripping Machinery

“…One of the most powerful features of these nanosystems is their switchability, which can be defined as the capacity to change properties in response to external stimuli; this feature lies at the core of their predisposition for smart nanotechnologies . In this context, although a variety of switches that mimic different macroscopic objects have already been established, a system that has remained underdeveloped is that of molecular grippers . These systems are defined by the ability to switch between an open (expanded) and a closed (contracted) state, which as a result enables reversible encapsulation of smaller molecular objects.…”

“…[2,22] In this context, although av ariety of switches that mimic different macroscopic objects have already been established, as ystem that has remained underdevelopedi st hat of molecular grippers. [23][24][25][26] These systems are defined by the ability to switch between an open (expanded) and ac losed (contracted) state, which as ar esult enables reversible encapsulation of smaller molecular objects. Such behavior is of interest for an umber of functional elements of nanotechnologies, includings ensors, [27][28][29] receptors, [30][31][32] nanoreactors, [33,34] transporters, [35,36] or elementsi nn anorobotics.…”