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For luminescent materials, the isomerization and intermolecular reactions of their double bonds are often undesirable because they cause a reduction in the luminescence properties of the π-system. Herein, we report a new methodology to simultaneously prevent isomerization and intermolecular reactions by utilizing the steric effect of a linked rotaxane structure. The ring units are covalently linked in order to prevent any undesired shuttling effect from occurring during isomerization. In addition, the insulated structure provides robust optical properties by prevention of intermolecular reactions. Bulky linked rotaxane structures on both sides of the N=N and C=C double bonds suppress E/Z isomerization; photoluminescence quantum yield (PLQY) measurements reveal that this results in suppression of PLQY reduction caused by isomerization. Moreover, an improvement in the stability under light irradiation and air atmosphere is demonstrated.
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http://dx.doi.org/10.1002/asia.202000350 | DOI Listing |
J Am Chem Soc
September 2025
Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080-3021, United States.
The direct transformation of C-H bonds into C-C bonds via cross-dehydrogenative coupling (CDC) represents a powerful strategy in synthetic chemistry, enabling streamlined bond construction without the need for prefunctionalized substrates. While traditional CDC approaches rely on polar mechanisms and preactivation of one of the C-H partners, recent advances have introduced radical-based strategies that employ a hydrogen atom transfer (HAT) approach to access carbon-centered radicals from unactivated substrates. Herein, we report a nickel-catalyzed CDC reaction between aldehydes and alkenes for the synthesis of skipped enones, leveraging aryl radicals as intermolecular HAT agents.
View Article and Find Full Text PDFOrg Lett
September 2025
National Key Laboratory of Advanced Drug Delivery and Release Systems, School of Pharmaceutical Sciences & Institute of Materia Medica, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250117, P. R. China.
A method for the conversion of isoxazoles into thiazoles by skeleton rearrangement has been achieved by an ammonium iodide-catalyzed cycloaddition protocol under mild conditions with a broad substrate scope and good functional group tolerance. Most appealingly, the reaction can proceed smoothly without the addition of any transition metal catalyst. Detailed mechanistic studies, including control experiments and key reaction intermediate characterization, reveal an intermolecular [3+2] cycloaddition reaction pathway.
View Article and Find Full Text PDFDalton Trans
September 2025
Department of Chemistry and Protein Research Center for Bio-Industry, Hankuk University of Foreign Studies, Yongin 17035, Republic of Korea.
The nanoscale environment within the void spaces of metal-organic frameworks (MOFs) can significantly influence the photoredox catalytic activity of encapsulated visible-light photoredox catalysts (PCs). To compare two isostructural PC@In-MOF systems, three cationic Ru(II) polypyridine complexes were successfully encapsulated within the mesoscale channels of the anionic framework of InTATB (HTATB = 4,4',4''--triazine-2,4,6-triyltribenzoic acid), which features a doubly interpenetrated framework structure. This encapsulation yielded three heterogenized visible-light PCs, RuL@InTATB, where L = 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), or 2,2'-bipyrazine (bpz).
View Article and Find Full Text PDFChem Sci
August 2025
College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei Research Center of the Basic Discipline of Synthetic Chemistry, Institute of Life Science and Green Development Hebei University Baoding Hebei 071002 P. R. China
The photocatalytic oxidative dipolar [3 + 2] cycloaddition reaction is a promising green approach for producing pyrrolo[2,1-]isoquinolines. However, developing sustainable cycloaddition methods with heterogeneous photocatalysts is still in its infancy, largely owing to their low reactivity and photostability. Herein, we propose a charge-oxygen synergy strategy through a dual-engineered covalent organic framework (COF) by integrating π-spacers with donor-acceptor motifs to promote intermolecular cycloaddition.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2025
Institute of Modern Optics and Center of Single-Molecule Science, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China.
Radical coupling reactions have been widely used in the synthesis of complex organic molecules, materials science, and drug research. However, restricted conditions or special catalysts are required to overcome the energy barrier and trigger the coupling reaction efficiently. In this study, we provide experimental evidence that the C─N radical coupling reactions can be significantly accelerated by an oriented external electric field (OEEF) under synchronous UV irradiation without a catalyst.
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