Search

Controlling the reciprocity between chemical reactivity and supramolecular structure is a topic of great interest in the emergence of molecular complexity. In this work, we investigate the effect of a covalent reaction as a trigger to depolymerize a supramolecular assembly. We focus on the impact of an in situ thiol–ene reaction on the (co)polymerization of three derivatives of benzene-1,3,5-tricarboxamide (BTA) monomers functionalized with cysteine, hexylcysteine, and alkyl side chains: Cys-BTA, HexCys-BTA, and a-BTA. Long supramolecular polymers of Cys-BTA can be depolymerized into short dimeric aggregates of HexCys-BTAvia the in situ thiol–ene reaction. Analysis of the system by time-resolved spectroscopy and light scattering unravels the fast dynamicity of the structures and the mechanism of depolymerization. Moreover, by intercalating the reactive Cys-BTA monomer into an unreactive inert polymer, the in situ thiol–ene reaction transforms the intercalator into a sequestrator and induces the depolymerization of the unreactive polymer. This work shows that the implementation of reactivity into supramolecular assemblies enables temporal control of depolymerization processes, which can bring us one step closer to understanding the interplay between non-covalent and covalent chemistry., We report on the controlled depolymerization of supramolecular 1D polymers into well-defined dimers triggered by a covalent reaction on the side chains of the monomer.

Structural and spatial organization are fundamental properties of biological systems that allow cells to regulate a wide range of biochemical processes. This organization is often transient and governed by external cues that initiate dynamic self-assembly processes. The construction of synthetic cell-like materials with similar properties requires the hierarchical and reversible organization of selected functional components on molecular scaffolds to dynamically regulate signaling pathways. The realization of such transient molecular programs in synthetic cells, however, remains underexplored due to the associated complexity of such hierarchical platforms. In this contribution, we effectuate dynamic spatial organization of effector protein subunits in a synthetic biomimetic compartment, a giant unilamellar vesicle (GUV), by associating in a reversible manner two fragments of a split luciferase to the membrane. This induces their structural dimerization, which consequently leads to the activation of enzymatic signaling. Importantly, such organization and activation are dynamic processes, and can be autonomously regulated – thus opening up avenues toward continuous spatiotemporal control over supramolecular organization and signaling in an artificial cell., Engineered artificial cells respond to environmental cues through a pre-programmed enzymatic machinery that induces spatio-structural organization and activation of effector proteins at the lipid membrane.

In contrast to biomacromolecules, synthetic polymers generally lack a defined monomer sequence, therefore one of the challenges of polymer chemists these days is gaining more control over the primary structure of synthetic polymers and oligomers. In this work, stereocontrolled sequence-defined oligomers were synthesised using a thiolactone-based platform. Step-wise elongation of the oligomer occurs via ring-opening of the thiolactone, resulting in the formation of stereocenters along the backbone. These initial studies indicate remarkable differences in the strength of non-covalent interactions in isotactic and atactic oligomers. Different side-chain moieties were introduced using alkyl halide building blocks and the synthetic protocol was succesfully optimised and automated. Furthermore, the possible post-synthesis modification of the oligomers was demonstrated using 'click' chemistry.

Non-covalently crosslinked polymeric networks are promising materials towards sustainable and recyclable plastics. Here, we present the post-functionalization of poly(dimethyl siloxane) (PDMS) with supramolecular moieties, attached as grafts to the PDMS backbone, to obtain recyclable PDMS networks. We select three different supramolecular motifs that differ in interaction strength and investigate how these differences affect the dynamic behavior of the networks. The introduction of dinitrohydrazones (hydz), which afford weak supramolecular interactions by π-stacking, resulted in a viscous material at room temperature. Stronger self-association was achieved by the introduction of benzene-1,3,5-carboxamides (BTAs) and ureidopyrimidinones (UPys), which self-assemble via triple and quadruple hydrogen bonding, respectively. This resulted in a thermoplastic elastomeric material for BTA-based PDMS and brittle materials for Upy-based PDMS. Time- and temperature-dependent mechanical measurements reveal that the dynamic nature of the supramolecular bonds becomes slower upon increasing the interaction strength. The polymers are fully recyclable by solvation or compression molding without the loss of material properties. Thereby, by using one linear PDMS backbone, we demonstrate how fundamentally different material properties are obtained by changing the supramolecular interaction strength and type of non-covalent crosslinks. These molecular insights broaden the scope and application of PDMS-based sustainable materials.

The transfer of the cooperative self-assembled fibrils to a gold substrate has been studied by means of scanning probe microscopy techniques revealing the crucial role of the early formation of a monolayer.