While supramolecular hosts capable of binding and transporting anions and ion pairs are now widely available, self-assembled architectures are still rare, even though they offer an inherent mechanism for the release of the guest ion(s). In this work, we report the dynamic covalent self-assembly of tripodal, urea-based anion cryptates that are held together by two orthoester bridgeheads. These hosts exhibit affinity for anions such as Cl À , Br À or I À in the moderate range that is typically advantageous for applications in membrane transport.In unprecedented experiments, we were able to dissociate the Cs•Cl ion pair by simultaneously assembling suitably sized orthoester hosts around the Cs + and the Cl À ion.

The dynamic covalent chemistry (DCvC) of the Si−O bond holds unique opportunities, but has rarely been employed to assemble discrete molecular architectures. This may be due to the harsh conditions required to initiate exchange reactions at silicon in aprotic solvents. Herein, we provide a comprehensive experimental and computational account on the reaction of trialkoxysilanes with alcohols and identify mild conditions for rapid exchange in aprotic solvents. Substituent, solvent and salt effects are uncovered, understood and exploited for the construction of sila‐orthoester cryptates. A sharp, divergent pH‐response of the obtained cages renders this substance class attractive for future applications well beyond host‐guest chemistry, for instance, in drug delivery.

The increased importance of RNA-based therapeutics comes with a need to develop next-generation stimuliresponsive systems capable of binding, transporting and releasing RNA oligomers. In this work, we describe triazoliumbased amphiphiles capable of siRNA binding and enzymeresponsive release of the nucleic acid payload. In aqueous medium, the amphiphile self-assembles into nanocarriers that can disintegrate upon the addition of esterase. Key to the molecular design is a self-immolative linker that is anchored to the triazolium moiety and acts as a positively-charged polar head group. We demonstrate that addition of esterase leads to a degradation cascade of the linker, leaving the neutral triazole compound unable to form complexes and therefore releasing the negatively-charged siRNA. The reported molecular design and overall approach may have broad utility beyond this proof-of-principle study, because the underlying CuAAC "click" chemistry allows bringing together three groups very efficiently as well as cleaving off one of the three groups under the mild action of an esterase enzyme.

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The dynamic covalent chemistry (DCvC) of the SiÀ O bond holds unique opportunities, but has rarely been employed to assemble discrete molecular architectures. This may be due to the harsh conditions required to initiate exchange reactions at silicon in aprotic solvents. Herein, we provide a comprehensive experimental and computational account on the reaction of trialkoxysilanes with alcohols and identify mild conditions for rapid exchange in aprotic solvents. Substituent, solvent and salt effects are uncovered, understood and exploited for the construction of silaorthoester cryptates. A sharp, divergent pH-response of the obtained cages renders this substance class attractive for future applications well beyond host-guest chemistry, for instance, in drug delivery.