4-[(2-Carb­oxy­eth­yl)amino]­benzoic acid monohydrate

In the title compound, C10H11NO4·H2O, the carboxyl group is twisted at a dihedral angle of 6.1 (3)° with respect to the benzene ring. In the crystal, the organic mol­ecules are linked by pairs of O—H⋯O hydrogen bonds involving both carboxyl groups, forming zigzag chains propagating along the b-axis direction. The water mol­ecules form [100] chains linked by O—H⋯O hydrogen bonds. The organic mol­ecule and water chains are cross-linked by N—H⋯Owater and Owater—H⋯O hydrogen bonds, generating (001) sheets

Strategies for Exploring Functions from Dynamic Combinatorial Libraries

Dynamic combinatorial chemistry (DCC) is a powerful approach for creating complex chemical systems, giving access to the studies of complexity and exploration of functionality in synthetic systems. However, compared with more advanced living systems, the man‐made chemical systems are still less functional, due to their limited complexity and insufficient kinetic control. Here we start by introducing strategies to enrich the complexity of dynamic combinatorial libraries (DCLs) for exploiting unexpected functions by increasing the species of building blocks and/or templates used. Then, we discuss how dynamic isomerization of photo‐switchable molecules help DCLs increase and alter the systemic complexity in‐situ. Multi‐phase DCLs will also be reviewed to thrive complexity and functionality across the interfaces. Finally, there will be a summary and outlook about remote kinetic control in DCLs that are realized by applying exogenous physical transduction signals of stress, light, heat and ultrasound.</p

Small-Molecule-based Supramolecular Plastics Mediated by Liquid-Liquid Phase Separation

Plastics are one of the most widely used polymeric materials. However, they are often undegradable and non-recyclable due to the very stable covalent bonds of macromolecules, causing environmental pollution and health problems. Here, we report that liquid-liquid phase separation (LLPS) could drive the formation of robust, stable, and sustainable plastics using small molecules. The LLPS process could sequester and concentrate solutes, strengthen the non-covalent association between molecules and produce a bulk material whose property was highly related to the encapsulated water amounts. It was a robust plastic with a remarkable Young's modulus of 139.5 MPa when the water content was low while became adhesive and could instantly self-heal with more absorbed water. Finally, responsiveness enabled the material to be highly recyclable. This work allowed us to understand the LLPS at the molecular level and demonstrated that LLPS is a promising approach to exploring eco-friendly supramolecular plastics that are potential substitutes for conventional polymers.</p

Self-Synthesizing Nanorods from Dynamic Combinatorial Libraries against Drug Resistant Cancer

Molecular self-assembly has been widely used to develop nanocarriers for drug delivery; however, most have unsatisfactory drug loading capacity (DLC) and the dilemma between stimuli-responsiveness and stability, stagnating their translational process. Here we overcame these drawbacks using dynamic combinatorial chemistry. A carrier molecule was spontaneously and quantitatively synthesized, aided by co-self-assembly with a template molecule and an anti-cancer drug doxorubicin (DOX) from a dynamic combinatorial library that was operated by disulfide exchange under thermodynamic control. The highly selective synthesis guaranteed a stable yet pH- and redox- responsive nanocarrier with a maximized DLC of 40.1% and an enhanced drug potency to fight DOX resistance in vitro and in vivo . Our findings suggested that harnessing the interplay between synthesis and self-assembly in complex chemical systems could yield functional nanomaterials for advanced applications

Strategies for Exploring Functions from Dynamic Combinatorial Libraries

Dynamic combinatorial chemistry (DCC) is a powerful approach for creating complex chemical systems, giving access to the studies of complexity and exploration of functionality in synthetic systems. However, compared with more advanced living systems, the man‐made chemical systems are still less functional, due to their limited complexity and insufficient kinetic control. Here we start by introducing strategies to enrich the complexity of dynamic combinatorial libraries (DCLs) for exploiting unexpected functions by increasing the species of building blocks and/or templates used. Then, we discuss how dynamic isomerization of photo‐switchable molecules help DCLs increase and alter the systemic complexity in‐situ. Multi‐phase DCLs will also be reviewed to thrive complexity and functionality across the interfaces. Finally, there will be a summary and outlook about remote kinetic control in DCLs that are realized by applying exogenous physical transduction signals of stress, light, heat and ultrasound.peerReviewe

Performance improvement induced by membrane treatment in proton exchange membrane water electrolysis cells

Hydrogen has been widely accepted as the best alternative energy carrier to store intermittent renewable energies. Proton exchange membrane water electrolysis (PEMWE) represents a promising technology to produce highly pure hydrogen with high efficiency and low footprint. While great progress has been made on components, materials and even fabrication processes, new materials or complicated processes still require refinement in the process of continuously improving PEMWE performance and durability. In this study, we demonstrate a facile treatment on membranes, aiming at improving cell performance at low costs. By adopting the hydration in DI water or 0.5 M H2SO4, or by varying the treatment sequence with the catalyst layer deposition, the PEMWE performance was tuned with the overpotential improvement as high as 50 mV at 2.0 A cm(-2). The PEMWE cells after different treatments were characterized both ex-situ and in-situ, and the mechanism was also proposed. The H2SO4 treatment swelled the micro micelle structure of the Nafion membranes, resulting in a higher proton conductivity and better cell performance compared with those from DI water treatment. In addition, the treatment sequence also had great impact, and the treatment after the catalyst layer deposition would result in better performance due to the reduced resistance and better kinetics. Not only the types of membrane, but also the thickness should be measured and reported when tested, which is more critical when compared across the published works from different groups. This work could also provide a guideline for future membrane treatment and PEMWE cell testing. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved

Supramolecular Plastics Processed from Small Molecule-based Coacervates

Supramolecular polymers self-assembled by small molecules are a type of new material with adaptive and biocompatible properties. However, the mechanical property of these materials is always weak, impeding their applications in practice. Here, we reported that coacervation can be used to explore robust and stable bulk materials without the compromise of responsiveness. The liquid-liquid separation process could sequester and concentrate solutes, which facilitated the non-covalent association of building blocks equipped with multiple binding sites and resulted in bulk materials with versatile properties that were highly related to the encapsulated water amounts. It was a robust plastic with a remarkable Young’s modulus of 139.53 4.74 MPa when the water content was about 5% while became adhesive and could instantly self-heal with more absorbed water. Moreover, the material was reusable and fully recyclable. Our findings suggest that coacervation offers a promising approach to constructing bulk materials using small molecules and new possibilities for the application of supramolecular chemistry