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Dynamic constitutional materials are constructed from reversibly connecting components adaptively self-assembling under the pressure of internal or external factors. Functional macromonomeric poly-(ethylene glycol) segments and 3D connecting cores can be used to conceive biomimetic dynamic constitutional frameworks (DCFs) for selective/adaptive biomolecular encapsulation of proteins, enzymes, etc. Gold nanoparticles (AuNps) can be involved as core connectors to expand the networks of DCFs at the nanoscale, thereby increasing the biomolecular encapsulation and activity. Efficient encapsulation of bovine carbonic anhydrase (bCA) in host matrixes is of tremendous importance for maintaining its stability, catalytic activity, and durability. In this paper, we demonstrate that AuNps-DCFs-bCA bioconjugates, synthesized via reversible imine/amino-carbonyl as sulfide-AuNps chemistries, assemble into nanometric aggregates of around 200 nm with high stability for bCA encapsulation. This system showed an impressive improved catalytic activity, more than 30 times higher than that of bCA alone. The Km values were two to three times lower compared to free bCA indicating a stronger affinity for bCA under encapsulation, while Vmax was higher. This performance is very promising for current state-of-the-art carbon dioxide capture systems with equivalent amounts of enzyme, even after heating for a prolonged period at 100 °C, translating into a direct perspective for enhancing flue gas capture and conversion performances. [ABSTRACT FROM AUTHOR]

Constructing artificial ion channels is a challenging task. Herein, the de novo design of transmembrane ion channels made up of amphiphilic peptide–oligourea chimeric helices is described. They consist of an oligourea segment (7‐mer) attached to the C‐terminus of a short peptide (8‐mer). Mass spectrometry (MS) and transmission electron microscopy (TEM) analyses show that in an aqueous solution, two of these chimeras (HPU‐E and HPU‐N) independently form defined oligomeric structures. TEM also shows that they form fiber bundles. The third related chimera HPU‐F does not oligomerize (MS) but forms spherical nanostructures (TEM). HPU‐E and HPU‐N exhibit anion transport activity across lipid bilayers via antiport mechanism (HPU‐N > HPU‐E). The anion selectivity of HPU‐N is Cl−>NO3− > Br−>SCN− > I− > AcO−>F−, which can be due to anion binding within the channels rather than size exclusion. Patch‐clamp data support HPU‐N's Cl− selectivity (PCl−/PI− = 3.26). X‐ray crystal structure (1.77 Å) of HPU‐N reveals well‐packed α‐helices, and cryo‐electron microscopy data shows the formation of nanotubes (13.7 Å diameter pores) and transmembrane channels. The study shows that α‐peptide–oligourea‐based de novo design can yield unique bioactive molecules with defined structures and functions. [ABSTRACT FROM AUTHOR]

Pyrene boxes, self‐assembled from 1,3,5,8‐pyrene‐tetrasulfonate anions, PTS4− and Guanidinium G+, amino‐guanidinium AG+ and hydrated alkali counter cations have been used for the encapsulation of 1,ω‐amino‐acids of variable lengths. The NMR spectroscopy illustrates that these systems are stable in aqueous solution and encapsulation process involves dynamic or fixed guest molecules within Pyrene box, depending of the nature of the counter‐cations. The amide bond coupling between the amino‐guanidinium AG+ and encapsulated 1,ω‐amino‐acid guests occur in water in the absence of coupling catalysts. The variable co‐encapsulation of the guests via multivalent stabilizing interactions shed light that chemical selection can be obtained from mixtures of 1,ω‐amino‐acids. Our study involving a comprehensive screening of 18 co‐crystal structures help to understand the in‐situ fixation of 1,ω‐amino‐acid guests and their accurate determination of unconventional structures under confinement. [ABSTRACT FROM AUTHOR]

This special collection presents original research articles and reviews that are connected to the multifaceted and rich chemistry of water. These works serve as an illustration of how, despite its apparent simplicity and ubiquity, water continues to be at the center of scientific exploration from a wide range of perspectives and employing the toolbox of modern‐day chemistry. [ABSTRACT FROM AUTHOR]

Understanding water transport mechanisms at the nanoscale level remains a challenge for theoretical chemical physics. Major advances in chemical synthesis have allowed us to discover new artificial water channels, rivaling with or even surpassing water conductance and selectivity of natural protein channels. In order to interpret experimental features and understand microscopic determinants for performance improvements, numerical approaches based on all-atom molecular dynamics simulations and enhanced sampling methods have been proposed. In this study, we quantify the influence of microscopic observables, such as channel radius and hydrogen bond connectivity, and of meso-scale features, such as the size of self-assembly blocks, on the permeation rate of a self-assembled nanocrystal-like artificial water channel. Although the absolute permeation rate extrapolated from these simulations is overestimated by one order of magnitude compared to the experimental measurement, the detailed analysis of several observed conductive patterns in large assemblies opens new pathways to scalable membranes with enhanced water conductance for the future design. [ABSTRACT FROM AUTHOR]

Innovative self-supported flat-sheet polyvinylidene fluoride (PVDF) membranes were developed incorporating amphiphilic I-quartet Artificial Water Channels (AWCs) and applied for membrane distillation (MD) and Dyes Ultrafiltration (UF). The presence of AWCs was aimed to increase the amount of water within hydrophobic PVDF pores increasing water permeability and preserving high selectivity and consequently to improve the MD and dyes UF performances. We explored novel strategies in which water channels structures contribute to water cluster stabilization and the increase of water (vapors or liquid) within hydrophobic pore structures. With this novel strategy in mind, three PVDF polymer grades with different molecular weights as well as the variation of their mass concentration as well as of AWCs were studied to shed in light their influence on the water permeability using a dead-end filtration setting. An enhanced water permeability of 75.3 L.m-2.h-1.bar-1 was attained for the PVDF-AWC hybrid membrane prepared using 16 wt% PVDF (530,000 g/mol) and 0.05 wt% AWCs when compared with a reference membrane with a water permeability of 30.6 L.m-2.h-1.bar-1. The MD performances of both membranes were assessed using a 35 g/L NaCl aqueous solution to yield a salt rejection of 95.3% and 85.2%, respectively. Furthermore, both the reference and the PVDF-AWC membranes showed improved separation performance in terms of rejection efficiency and dye permeability for binary dyes mixture as compared to single dyes. Among all the tested membranes, while methylene blue was completely removed in both cases, the 14 wt% PVDF membrane incorporating 0.075 wt% AWC showed a methyl orange rejection efficiency of up to 99.8% compared to 98.4% for its reference membrane. This hybrid membrane also displayed an almost doubled filtered dye feed permeability of 84 L.m-2.h-1.bar-1, compared to 40 L.m-2.h-1.bar-1 for its 14 wt% PVDF reference membrane. [ABSTRACT FROM AUTHOR]

Catalytic CO2 methanation is of particular significance and growing interest due to its applications in many important industrial fields. The development of advanced heterogeneous catalysts for CO2 methanation depends predominantly on the rational regulation of metal–support interaction (MSI), which remains challenging despite recent progress. Here, we develop a new heterogeneous catalyst, TiH2-supported Ru nanoparticles (NPs), which features notable electron transfer from the TiH2 support to Ru NPs and enhanced capability of CO intermediate activation for CO2 methanation, distinct from TiO2-supported Ru catalysts synthesized under similar mild conditions. The electron transfer behavior and hydrogen spillover effect in TiH2-supported Ru NPs (denoted as mRTH, where m refers to the mass loading of the RuCl3 precursor in mg) are optimized at a moderate Ru loading level of 9.8 wt% in 100RTH, where the impacts of Ru loading on CO intermediate activation, H2 activation and catalyst surface hydration are synergistically balanced. When evaluated at 200 °C under 4 bar pressure, 100RTH delivers a notable CH4 selectivity of 99.8% and a superior CH4 production rate of 168.7 mmol h−1 gRu−1, which is 21.1 times more active than pure Ru NPs. Our work provides valuable insights into the MSI-directed development of heterogeneous catalysts for highly efficient CO2 conversion and utilization. [ABSTRACT FROM AUTHOR]