2020, Izak-Nau, Emilia, Campagna, Davide, Baumann, Christoph, Göstl, Robert

Over the past decades, it became clear that next to heat and light, pericyclic reactions can be induced mechanochemically when the reacting motifs are embedded as latent force-responsive groups (mechanophores) into polymer architectures. Not only does this enable a variety of functions and applications on a material level, but moreover grants access to symmetry-forbidden reaction products with respect to the Woodward-Hoffmann rules. The latter indicates that polymer mechanochemistry follows its own set of rules that, however, regarding underlying mechanisms and design rationales is far from being holistically understood. Here we review the existing body of literature and identify common structural features and substitution prerequisites to the polymer framework shining light on the differences between polymer mechanochemical pericyclic reactions and their traditional counterparts. By this, we believe to contribute to the major challenge of not only retrospectively describing force-induced reactivity but eventually finding a common molecular design guideline. © The Royal Society of Chemistry 2020.

2019, Buzzacchera, Irene, Xiao, Qi, Han, Hong, Rahimi, Khosrow, Li, Shangda, Kostina, Nina Yu, Toebes, B. Jelle, Wilner, Samantha E., Möller, Martin, Rodriguez-Emmenegger, Cesar, Baumgart, Tobias, Wilson, Daniela A., Wilson, Christopher J., Klein, Michael L., Percec, Virgil

Natural, including plant, and synthetic phenolic acids are employed as building blocks for the synthesis of constitutional isomeric libraries of self-assembling dendrons and dendrimers that are the simplest examples of programmed synthetic macromolecules. Amphiphilic Janus dendrimers are synthesized from a diversity of building blocks including natural phenolic acids. They self-assemble in water or buffer into vesicular dendrimersomes employed as biological membrane mimics, hybrid and synthetic cells. These dendrimersomes are predominantly uni- or multilamellar vesicles with size and polydispersity that is predicted by their primary structure. However, in numerous cases, unilamellar dendrimersomes completely free of multilamellar assemblies are desirable. Here, we report the synthesis and structural analysis of a library containing 13 amphiphilic Janus dendrimers containing linear and branched alkyl chains on their hydrophobic part. They were prepared by an optimized iterative modular synthesis starting from natural phenolic acids. Monodisperse dendrimersomes were prepared by injection and giant polydisperse by hydration. Both were structurally characterized to select the molecular design principles that provide unilamellar dendrimersomes in higher yields and shorter reaction times than under previously used reaction conditions. These dendrimersomes are expected to provide important tools for synthetic cell biology, encapsulation, and delivery.