Abstract Four cyanoethylene-functionalized pyrene derivatives were synthesized via Suzuki coupling and subsequent hydrolysis-triggered lactonization. Substituent effects exert pronounced and consistent modulation of photophysical properties both in dilute solution and in the aggregated state. TriFPy exhibited the most significant redshift centered at 508 nm in solution and the highest photoluminescence quantum yield (ΦFL = 60%). BuTriFPy, possessing the smallest calculated HOMO–LUMO energy gap (ΔEg = 3.14 eV), displayed dual emission in dilute solution and the longest solid-state fluorescence lifetime (τ = 3.34 ns). The excellent mechanofluorochromism (MFC) performance and reversible switching behavior of the four materials were rationalized and experimentally corroborated by their microcrystalline architectures and corresponding X-ray diffraction (XRD) patterns. Notably, polymer-induced emission enhancement (2–5 times) and blueshifted emission represent promising design strategies that broaden the applicability of these materials in optoelectronic and flexible material applications. Moreover, the PhPy-based fluorescent extractant can realize high-contrast and high-sensitivity visual extraction of latent fingerprints (LFPs).
Abstract Currently, the protocol to achieve imidazo[2,1-a]isoquinolines from isoquinolinium N-ylides was rare. Herein, a novel metal-free approach to imidazo[2,1-a]isoquinolines from 2H-azirines and isoquinolinium N-ylides has been successfully developed in a one-pot way, in which 2H-azirines acted as 2-atom synthons to construct azaheterocycles. The investigation indicated that the protocol to synthesize imidazo[2,1-a]isoquinolines might proceed via a radical pathway, and this reaction underwent a cascade of formal [3 + 2] annulation, ring-opening, and elimination/aromatization processes.
Abstract A direct C3-cyanation protocol for indole derivatives has been established using cyanobenziodoxolone (CBX) as the cyanating reagent and hexafluoroisopropanol (HFIP) as the solvent. This transformation proceeds efficiently under mild, catalyst-free, and inert-atmosphere-free conditions, providing a practical approach for the C3-cyanation of electronically favored indole substrates.
Abstract Photocatalytic fluoroalkylative cyclization of alkenes provides an efficient approach to fluorinated heterocycles, yet existing methods generally require distinct radical precursors for different fluoroalkyl groups. Herein, we report a visible-light-induced ruthenium-catalyzed fluoroalkylative cyclization of o-alkenylbenzamides using readily available fluoroalkylsulfonyl chlorides as a unified family of radical precursors. This protocol enables the efficient synthesis of a broad range of fluoroalkylated iminoisobenzofurans bearing trifluoromethyl, difluoromethyl, and perfluoroalkyl substituents under mild conditions with a broad substrate scope and good functional group compatibility. Mechanistic studies support a photocatalytic radical pathway initiated by single-electron reduction of the fluoroalkylsulfonyl chlorides.
Abstract Succinimide-fused cyclobutenes are valuable building blocks for the synthesis of highly functionalized polycyclic structures. However, methods for constructing these structures—especially the N-aryl ones—remain limited. Herein, we provided an improved and rapid access to N-substituted succinimide-fused cyclobutenes by leveraging the copper-catalyzed Chan-Lam coupling. Desired products are afforded in 45–99% yields. Furthermore, this method features a broad substrate scope and good functional group compatibility.
