Dynamic Functional Molecular Systems: From Supramolecular Structures to Multi‐Component Machinery and to Molecular Cybernetics

This essay highlights the role of single and multiple reversible self‐sorting events for the development of responsive multi‐component structures as well as multi‐state transformations, devices and machinery. Recent examples illustrate how distinct molecular devices are spatiotemporarily interconnected by chemical signaling to act as integrated machinery and highlight the enormous potential of molecular cybernetics.     

Supramolecular Capsules Derived from Calixpyrrole Scaffolds

This review article describes recent results obtained in the self-assembly of supramolecular capsules derived from calixpyrrole components. Due to their ease of synthesis, calix[4]pyrroles are by far the most typically used units in these systems. A clear conformational and structural analogy exists between calix[4]arenes and calix[4]pyrroles. However, to date, the number of examples in the literature that use calix[4]pyrrole scaffolds instead of calix[4]arenes for the construction of supramolecular capsules is still meager. Four different approaches are considered for the use of calix[4]pyrrole derivatives in the assembly of molecular capsules. Firstly, in an analogous manner to resorcin[4]arenes and pyrogallol[4]arenes, aryl-extended calix[4]pyrroles with hydroxyl groups in their upper rim self-assemble through direct or mediated rim-to-rim interactions into capsular aggregates. Secondly, aryl-extended calix[4]pyrroles having non-complementary hydrogen-bonding groups in their upper rim form dimeric templated capsules with suitable substrates. Thirdly, the elaboration of the upper rim of the calix[4]pyrroles with urea groups affords dimeric capsules with polar functionalized interiors that closely resemble their tetraurea calix[4]arene analogs. Finally, the chemical modification of the pyrrole units of octamethyl calix[4]pyrrole into tetrathiafulvalene derivatives yields dimeric capsules induced by anion coordination that display interesting properties in the binding of electron-poor guests.     

Self‐Assembly Processes of Pd(II)‐ and Pt(II)‐Linked Discrete Self‐Assemblies Revealed by QASAP

Recent progress in the understanding of discrete coordination self‐assembly processes is summarized. Aiming to make the problems in the investigation of molecular self‐assembly processes clear, a novel method (QASAP: quantitative analysis of self‐assembly process) to obtain the information about all intermediates that are transiently produced during the self‐assembly in an indirect way was introduced. Through the application of QASAP to over ten kinds of Pd(II)‐ or Pt(II)‐linked discrete coordination self‐assemblies, similarities between molecular self‐assembly and protein folding, general principles underlying coordination self‐assembly, and the mechanism of homochiral self‐sorting along the self‐assembly pathway have been revealed and are discussed below.     

Orthogonal Light-Dependent Membrane Adhesion Induces Social Self-Sorting and Member-Specific DNA Communication in Synthetic Cell Communities

Developing orthogonal chemical communication pathways in diverse synthetic cell communities is a considerable challenge due to the increased crosstalk and interference associated with large numbers of different types of sender-receiver pairs. Herein, the authors control which sender-receiver pairs communicate in a three-membered community of synthetic cells through red and blue light illumination. Semipermeable protein-polymer-based synthetic cells (proteinosomes) with complementary membrane-attached protein adhesion communicate through single-stranded DNA oligomers and synergistically process biochemical information within a community consisting of one sender and two different receiver populations. Different pairs of red and blue light-responsive protein-protein interactions act as membrane adhesion mediators between the sender and receivers such that they self-assemble and socially self-sort into different multicellular structures under red and blue light. Consequently, distinct sender-receiver pairs come into the signaling range depending on the light illumination and are able to communicate specifically without activation of the other receiver population. Overall, this work shows how photoswitchable membrane adhesion gives rise to different self-sorting protocell patterns that mediate member-specific DNA-based communication in ternary populations of synthetic cells and provides a step towards the design of orthogonal chemical communication networks in diverse communities of synthetic cells.