Supramolecular systems chemistry

Abstract

The field of supramolecular chemistry focuses on the non-covalent interactions between molecules that give rise to molecular recognition and self-assembly processes. Since most non-covalent interactions are relatively weak and form and break without significant activation barriers, many supramolecular systems are under thermodynamic control. Hence, traditionally, supramolecular chemistry has focused predominantly on systems at equilibrium. However, more recently, self-assembly processes that are governed by kinetics, where the outcome of the assembly process is dictated by the assembly pathway rather than the free energy of the final assembled state, are becoming topical. Within the kinetic regime it is possible to distinguish between systems that reside in a kinetic trap and systems that are far from equilibrium and require a continuous supply of energy to maintain a stationary state. In particular, the latter systems have vast functional potential, as they allow, in principle, for more elaborate structural and functional diversity of self-assembled systems - indeed, life is a prime example of a far-from-equilibrium system. In this Review, we compare the different thermodynamic regimes using some selected examples and discuss some of the challenges that need to be addressed when developing new functional supramolecular systems.

Controlling supramolecular polymerization through multicomponent self‐assembly

“…This strategy is an elegant approach for kinetically controlled product formation in supramolecular materials, via the combination of reversible covalent bonds and noncovalent interactions. [420][421][422] The strategies that have been highlighted so far, demonstrate the impact of and potential for kinetic control in supramolecular polymeric assemblies of controlled length and architecture, driven by epitaxial crystallization of blocked copolymers, 31,350 or by the combination of reversible covalent bonds and noncovalent interactions in macrocyclic unimers. 10,[420][421][422] Alternatively, the manipulation of self-assembly pathways was very recently achieved via the rational design of selfassembling small molecular weight building blocks by three different groups.…”

“…[420][421][422] The strategies that have been highlighted so far, demonstrate the impact of and potential for kinetic control in supramolecular polymeric assemblies of controlled length and architecture, driven by epitaxial crystallization of blocked copolymers, 31,350 or by the combination of reversible covalent bonds and noncovalent interactions in macrocyclic unimers. 10,[420][421][422] Alternatively, the manipulation of self-assembly pathways was very recently achieved via the rational design of selfassembling small molecular weight building blocks by three different groups. [423][424][425] Sugiyasu, Takeuchi and coworkers have been able to show that seed-induced growth in combination with a competing off-pathway aggregation leads to a "living" supramolecular polymerization of a Zn(II)-porphyrin dye ZnP4 in apolar methylcyclohexan (MCH).…”

All in a spin

“…2 Systems chemistry -the study of supramolecular assemblies and the nature of the interactions within them -is one field of chemical research that seeks to answer this fundamental question. 3 A grand challenge of systems chemistry is to develop "bottom-up" methods to systematically engineer supramolecular ensembles of simple molecules from which specific, targeted and externally controllable functionality can emerge, 4 such as the creation of artificial living cells. 5 Now, writing in Nature Chemistry, a team led by Andrew Goodwin and François-Xavier Coudert has pioneered a novel approach towards the understanding and control of emergent behaviour by carving out a conceptual mapping between the collective structural behaviour of supramolecular assemblies of coordination polymer chains and the ostensibly unrelated field of frustrated magnetism.…”

Dynamic force spectroscopy of synthetic oligorotaxane foldamers

“…The work performed by these natural molecular motors is related to their dynamics in solution, and to the force exerted by the molecule to drive the relevant process in one direction. The invention of synthetic routes to wholly artificial molecular machines with highly precise and controlled architectures has led to the production of amazing molecules able to perform mechanical tasks (3)(4)(5)(6)(7). Their integration into materials such as metal-organic frameworks (8) or polymer gels (9, 10) has been described recently.…”