Intramolecular Charge Transfer‐Regulated Isomeric Covalent Organic Frameworks for Multiple Solvent‐Response

Small, Journal Year: 2025, Volume and Issue: unknown

Published: March 25, 2025

Stimulus-responsive covalent organic frameworks (COFs) own color-switching characteristics when exposed to external stimuli. However, the investigations on multiple solvent-responsive COFs remain a challenge due synthetic difficulties and uncontrollable charge transfer process toward various solvents. In this contribution, two novel isomeric with regulated intramolecular (ICT) by modulating distance between donor/acceptor linkage are synthesized. The as-prepared exhibited significantly distinct solvatochromic behaviors in water, acid, halogenated solvents, respectively. These functions attributed enhancement degrees of ICT hydrogen bond interactions, protonation halogen/π addition, employed as stimulation-responsive powder or ink, displaying excellent image data encryption performances. work can not only offer viewpoint for creation but also expand COFs' potential applications information anti-counterfeiting.

Language: Английский

Flexible Single‐Atom Cesium Sites on Amorphous MgO Nano‐Cushions for Enhanced CO₂‐Involved Multi‐Step Reactions

Small, Journal Year: 2025, Volume and Issue: unknown

Published: April 24, 2025

Abstract Single atomic sites (SAs) face challenges in catalyzing complex chemical processes involving multiple intermediates due to rigid coordination environments, steric hindrances, and limited activation behaviors. Herein, an alloying‐mediated element repartition method is developed synthesize flexible cesium single‐atom catalysts, anchoring Cs single on precisely controlled amorphous‐MgO/crystalline NbC hetero‐phase nano‐supports. The amorphousMgO(a‐MgO) equipped 1 ‐a‐MgO/NbC achieves 91% yield the cyclization of CO 2 with 2‐aminobenzonitrile within a gas–liquid–solid triphasic system, outperforming its counterpart fabricated crystalline MgO, ‐c‐MgO/NbC catalyst (only 23%). shows excellent tolerance various functional groups sustainable catalysis, especially removing traditional requirement for high‐pressure conditions additives. Operando spectroscopic characterizations theoretical calculations demonstrate that sandwich‐structural enhances consecutive through vertically adsorbed configurations during C‐N coupling N‐heterocyclic ring formation. SAs supported by a‐MgO nano‐cushions allow adaptability dynamic transformations via tensile Cs‐O compressive Mg─O bonds, ultimately reducing energy barriers critical rearrangement isomerization steps. This study provides valuable insights into designing SACs overcome limitations support interfaces, thereby enhancing performance toward multi‐intermediate conversion heterogeneous catalytic transformations.

Language: Английский

Asymmetric heterogeneous catalysis using crystalline porous materials

Chemical Society Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

This review discusses the design and synthesis methods asymmetric catalytic applications of chiral crystalline porous materials, focusing on heterogeneous reactions control mechanisms.

Language: Английский