Synthesis and gelation capability of Fmoc and Boc mono-substituted cyclo(L-Lys-L-Lys)s

Efficient Hydro- and Organogelation by Minimalistic Diketopiperazines Containing a Highly Insoluble Aggregation-Induced, Blue-Shifted Emission Luminophore*

We report the synthesis, gelation abilities and aggregation‐induced, blue‐shifted emission (AIBSE) properties of two minimalistic diketopiperazine‐based gelators. Despite containing a highly insoluble luminophore that makes up more than half of their respective molecular masses, efficient hydrogelation by multiple stimuli for one and efficient organogelation for the other compound are reported. Insights into the aggregation and gelation properties were gained through examination of the photophysical and material properties of selected gels, which are representative of the different modes of gelation. The synthesis of the gelators is highly modular and based on readily available amino acid building blocks, allowing the efficient and rapid diversification of these core structures and fine‐tuning of gel properties.

Diketopiperazine Gels: New Horizons from the Self-Assembly of Cyclic Dipeptides

Cyclodipeptides (CDPs) or 2,5-diketopiperazines (DKPs) can exert a variety of biological activities and display pronounced resistance against enzymatic hydrolysis as well as a propensity towards self-assembly into gels, relative to the linear-dipeptide counterparts. They have attracted great interest in a variety of fields spanning from functional materials to drug discovery. This concise review will analyze the latest advancements in their synthesis, self-assembly into gels, and their more innovative applications.

Rapidly Recoverable Thixotropic Hydrogels from the Racemate of Chiral OFm Monosubstituted Cyclo(Glu-Glu) Derivatives

Both chiral OFm monosubstituted cyclo(l-Glu-l-Glu) and cyclo(d-Glu-d-Glu) display a robust gelation ability in a variety of organic solvents and water. In contrast to an individual enantiomer, their racemate can form rapidly recoverable thixotropic hydrogels with a remarkably shorter thixotropic recovery time. This unexpected thixotropic behavior is induced by the random arrangement of d- and l-enantiomers in the cell units, leading to the formation of "pseudoracemate", noncrystalline self-assemblies in the resulting 3D fibrous network.

Molecular Self-Assembly of Cyclic Dipeptide Derivatives and Their Applications

Cyclic dipeptides (CDPs) are heterocyclic 2,5-diketopiperazines with exceptional structural rigidity, enzymatic stability, and biological activity, exhibiting a substantial tendency to take part in intermolecular interactions. Strong intermolecular interactions driven by unique hydrogen bonding patterns render CDPs with a high propensity to undergo molecular self-assembly. In this Review, the aim is to provide a comprehensive summary of design strategies used to engineer the molecular self-assembly of CDPs into functional nano- and micro-architectures and molecular gels with potential applications in biomedical and materials engineering fields.