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With ethylene-vinyl acetate-glycidyl methacrylate (EVM-GMA) rubber as matrix, γ-aminopropyltriethoxysilane (APTES) as grafting monomer and azodicarbonamide as foaming agent, double crosslinked foaming materials were prepared by combination of water crosslinking and peroxide crosslinking. The cell morphology, dynamic mecha-nical properties, and physical and mechanical properties of the foaming materials were investigated by scanning electron microscopy, dynamic mechanical property spectrometer and electronic universal tes-ting machine. The results showed that the double crosslinked foaming process could be realized, and the crosslinking network formed by water crosslin-king could effectively improve the uniformity and dispersion of cell size. When the amount of dicumyl peroxide was 0.25 phr (mass), the double crosslinked foam material had the narrowest cell size distribution, the best foaming effect, and better energy absorption effect, which was suitable for application of damping materials.

Despite the rapid development of thermally activated delayed fluorescent (TADF) materials, developing organic light‐emitting diodes (OLEDs) with small efficiency roll‐off remains a formidable challenge. Herein, we have designed a TADF molecule (mClSFO) based on the spiro fluorene skeleton. The highly twisted structure and multiple charge‐transfer channels effectively suppress aggregation‐caused quenching (ACQ) and endow mClSFO with excellent exciton dynamic properties to reduce efficiency roll‐off. Fast radiative rate (kr) and rapid reverse intersystem crossing (RISC) rate (kRISC) of 1.6×107 s−1 and 1.07×106 s−1, respectively, are obtained in mClSFO. As a result, OLEDs based on mClSFO obtain impressive maximum external quantum efficiency (EQEmax) exceeding 20 % across a wide doping concentration range of 10–60 wt %. 30 wt % doped OLED exhibits an EQEmax of 23.1 % with a small efficiency roll‐off, maintaining an EQE of 18.6 % at 1000 cd m−2. The small efficiency roll‐off and low concentration dependence observed in the TADF emitter underscore its significant potential. [ABSTRACT FROM AUTHOR]

Near ultraviolet (NUV) organic light‐emitting diodes (OLEDs) have great advantages in the field of light excitation sources, chemical and biological sensors, etc. However, the molecular design of NUV emitters still faces the challenges of spectral broadening and red‐shift. In this study, attaching weak oxygen‐bridged triarylboron acceptor to weak carbazolyl donor is able to address intractable problems by weakening donor–acceptor (D–A) charge transfer. Simultaneously, sterically wrapped and modified oxygen‐bridged triarylboron acceptor by bulk substituents (multiple carbazolyl) can suppress intermolecular π–π stacking through steric hindrance effect. These design strategies are able to obtain short‐wavelength, narrow‐band emission, and great color purity. As a result, carbazolyl derivatives xCz‐BO‐based (x = 2, 3, 4, 5) emitters show EL emission peaks from 406 to 422 nm in the NUV light region and small full‐width at half‐maximums (FWHMs) of 32–41 nm over a wide range of dopant concentrations (10–40 wt.%). The most violet Commission International de I'Eclairage (CIE) color coordinate is (0.16, 0.03). Moreover, 5Cz‐BO can be employed as host for vacuum‐/solution‐processed blue OLEDs and these devices exhibit high performance with EQEs of over 20%. [ABSTRACT FROM AUTHOR]

Developing narrowband blue multiple resonance (MR) organic emitters with Commission Internationale de L'Eclairage (CIE) y coordinates <0.1 is essential for advanced display technologies. This study proposes a deep‐blue thermally activated delayed fluorescence (TADF) emitter, named 2BNO, which integrates two independent MR cores. Unlike many TADF materials with single‐bonded dual emitting cores, 2BNO utilizes a steric hindrance‐assisted fluorene bridge to achieve an orthorhombic molecular structure. The dual‐core MR‐TADF emitter shows enhanced light absorption and a high photoluminescence quantum yield. Notably, the emission of 2BNO is not significantly redshifted compared to single‐core compounds and maintains a narrow full width at half‐maximum (FWHM) of 24 nm with CIE coordinates of (0.147, 0.041) in 2Me‐THF solution, nearing the BT.2020 blue standard. Organic light‐emitting diodes (OLEDs) incorporating 2BNO as the emitter exhibit deep‐blue emission at 460 nm with a narrow FWHM of 29 nm and CIE coordinates of (0.14, 0.09). The dual emitting core design significantly improves device efficiency, achieving a high external quantum efficiency (EQE) of 19.8%. The dual‐core molecular design strategy in this work is demonstrated to be effective in promoting the efficiency of the TADF emitters while preserving deep‐blue color purity. [ABSTRACT FROM AUTHOR]

ABSTRACT A salamo‐type bis‐oxime ligand H2L was synthesized, which reacted with Ni (NO3)2·6H2O in different reaction solvents to synthesize two novel heptanuclear Ni (II) complexes: [Ni7(L)3(μ3‐OH)8(EtOH)6]·2CH2Cl2 (1) and [Ni7(L)3(μ3‐OMe)2(μ3‐OH)6(MeOH)6]·CH2Cl2 (2). X‐ray crystal diffraction results showed that each Ni (II) ion exhibits a distorted octahedral geometry. Its uniqueness lies in the fact that the Ni (II) ion in Complex 1 not only coordinates with ligand units but also coordinates with ethanol solvent molecules and water molecules participating in bridging. Complex 2 is composed of water molecules and methanol molecules connected together. Interestingly, the coordination mode is different due to the different reaction solvents. The energy gap changes of the ligand, and its complexes were then explored by DFT calculations. In addition, the influence of the weak interaction force was confirmed through the in‐depth study of electrostatic potential, IRI, freedom analysis, and Hirshfeld surfaces analyses, which is important for explaining the formation of reaction sites and supramolecular structures. UV‐visible spectrometric titration tests showed that the binding ratios of the ligand to Ni (II) ions are all 3:7, which is consistent with the crystal structure. Finally, fluorescence characterization studies showed that both complexes exhibited reduced fluorescence compared to H2L. [ABSTRACT FROM AUTHOR]

A general and efficient photocatalytic annulation‐carbohalogenation of 1,7‐enynes with a wide variety of alkyl halides was reported, which led to the atom‐economic synthesis of functionalized 3,4‐dihydronaphthalen‐1(2H)‐ones with good yields and high stereoselectivity under the mild and oxidant‐free conditions. The reaction demonstrated remarkable compatibility regarding alkyl halides as bifunctional reagents, such as ethyl 2‐bromo‐2,2‐difluoroacetate, ethyl 2,2‐difluoro‐2‐iodoacetate, perfluorobutyl iodide, bromotrichloromethane, and diethyl 2‐bromomalonate, and enabled wide substrate scope, high functional group tolerance, and 100% atom utilization. [ABSTRACT FROM AUTHOR]

A novel radical‐induced annulation/1,8‐halosulfonylation of β‐alkynyl ketones with haloaryl diazonium tetrafluoroborates and DABCO.bis(sulfur dioxide) was first achieved via the cleavage/recombination of C(sp3)−C(sp3) and C(sp2)‐halogen bonds, from which 47 examples of sulfone‐containing 1,3‐dimethylene‐substituted (Z,Z)‐isobenzofurans as single stereoisomers were synthesized in generally good yields. This multicomponent pathway is proposed to proceed through the in‐situ generation of arylsulfonyl radicals, followed by selective radical addition‐cyclization and ring‐opening of the cyclopropyl unit as well as C(sp2)‐halogen bond cleavage, resulting in the consecutive construction of three new chemical bonds, including C−S, C−O and C‐halogen bonds. [ABSTRACT FROM AUTHOR]

An efficient protocol for C−O bond formation from Csp2−X (X=Br, Cl) bond‐containing compounds and alkyl alcohols in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) as catalyst and base under mild conditions is described. The densely functionalized 2(5H)‐furanone products can be generally obtained in moderate to excellent yields via a metal‐free protocol at room temperature without added solvent. Killing two birds with one stone: A C−O bond formation reaction at room temperature in moderate to excellent yields is described. The reaction uses DABCO as both the base and catalyst. [ABSTRACT FROM AUTHOR]