Reactions in Dynamic Self‐Assemblies

Abstract

The dynamic processes in self‐assemblies are involved in numerous domains that span throughout the modern aspects of chemical sciences, going from fundamental investigations into the origin of life to the most striking technological applications in medicine or electronics. This chapter aims at providing the reader with a brief overview of the concepts that link chemical reactivity with dynamic templates and catalysts made of large supramolecular assemblies. Specifically, we discuss kinetic and thermodynamic aspects of selected examples depending on (i) the nature of the matrix — that is, micelles, vesicles, liquid crystals, and gels; (ii) the nature of their constituents — that is, surfactants, block copolymers, bioactive macromolecules; and (iii) the nature of the chemical transformations that are performed — that is, reaction of small organic molecules, biomolecules, polymerizations, nanoparticle formation, and also reactions that involve the constituents of the matrix themselves as observed, for instance, in self‐reproducing systems. In each section, we combine original papers that paved the field together with more recent works of particular interest; several reviews are also referenced to help in accessing a more comprehensive literature.

Kinetically controlled phenomena in dynamic combinatorial libraries

“…Dynamic combinatorial self-replication of large length scale self-assemblies was recently reviewed by Giuseppone. 35,36 Precipitation-driven self-sorting Kinetically controlled transformations of DCLs are not confined to a single phase, i.e. dilute solution.…”

Dynamic combinatorial/covalent chemistry: a tool to read, generate and modulate the bioactivity of compounds and compound mixtures

“…323 Supramolecular interactions between the members of an equilibrated DCL under thermodynamic control are a prerequisite for setting up self-replicating systems. 13,14,[66][67][68] A simplified concept of how a self-replicating system based on DCC could work is illustrated in Scheme 5. It closely resembles the finding of a potential binder for a given biological substrate, such as an enzyme, as described earlier.…”

“…If selective molecular interactions of one pair of building blocks with their corresponding reaction product are possible, the latter serves as a template, which helps to place complementary reacting building blocks in a favourable 3D arrangement to form a ternary complex. Upon pseudo-unimolecular reaction (occurring at an accelerated rate as a result of the binding to the template), this ternary complex is transformed into a duplex structure, and dissociation of this duplex affords the free condensation product, which can then serve as a new template for the next reaction sequence 13,67,68,324 (Scheme 5). To allow efficient dissociation and avoid product inhibition, the duplex structure should not be too stable.…”

“…45 Selfreplicating systems, in particular those based on self-templation processes, are of major biological interest for understanding how molecular systems at the origin of life became able to pass structural information from one molecule to another in view of selectively reproducing themselves. 14,68,325 Philp and co-workers, 324 as well as Terfort and von Kiedrowski, 326 used reversible imine formation as the condensation reaction and multiple hydrogen bonding 324 or an amidinium-carboxylate salt bridge 326 an even more efficient catalyst for the formation of the selfreplicating imine. 324 In the example of small peptide-based DCLs, Ashkenasy and co-workers demonstrated that product formation in self-replicating systems depends on the autocatalytic efficiency of the self-replicator and its thermodynamic stability, exemplified by the folding and unfolding capability of coiled peptide structures.…”

“…to selectively transport or release molecules in a biological context. Building DCLs by reversible covalent bond formation has been reviewed for receptor design, 12,30,[51][52][53][54][55][56][57][58][59][60] drug discovery, 12,33,51,52,[61][62][63][64] dynamic resolution, 40 self-sorting, 65 self-replication, [10][11][12][13][14]59,[66][67][68] DNAtemplated synthesis, 69,70 catalysis, 12,57,71 sensing, 36,37,56,72 the controlled release of bioactive compounds [37][38][39] and for various aspects in materials science. 11,12,30,39,[42][43][44]…”