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排序方式: 共有813条查询结果,搜索用时 78 毫秒
811.
Jonas Schmidt Dr. Luis I. Domenianni Marcel Leuschner Prof. Dr. Andreas Gansäuer Prof. Dr. Peter Vöhringer 《Angewandte Chemie (International ed. in English)》2023,62(35):e202307178
Titanium-based catalysis in single electron transfer (SET) steps has evolved into a versatile approach for the synthesis of fine chemicals and first attempts have recently been made to enhance its sustainability by merging it with photo-redox (PR) catalysis. Here, we explore the photochemical principles of all-Ti-based SET-PR-catalysis, i.e. in the absence of a precious metal PR-co-catalyst. By combining time-resolved emission with ultraviolet-pump/mid-infrared-probe (UV/MIR) spectroscopy on femtosecond-to-microsecond time scales we quantify the dynamics of the critical events of entry into the catalytic cycle; namely, the singlet-triplet interconversion of the do-it-all titanocene(IV) PR-catalyst and its one-electron reduction by a sacrificial amine electron donor. The results highlight the importance of the PR-catalyst's singlet-triplet gap as a design guide for future improvements. 相似文献
812.
Yihang Jiao Zijian Chen Dr. Weidong Qiu Hongwei Xie Jiaji Yang Dr. Xiaomei Peng Dr. Wentao Xie Qing Gu Dr. Mengke Li Dr. Kunkun Liu Prof. Shi-Jian Su 《Angewandte Chemie (International ed. in English)》2023,62(38):e202309104
Polychlorinated (hetero)arenes have shown great promise for organic optoelectronics applications. However, the harsh synthetic routes for polychlorinated compounds and the possible luminescence quenching from the compact intermolecular π–π stacking induced by chlorine atoms limit their investigations and applications in luminescent materials. Herein, two isomeric polychlorinated polycyclic aromatic hydrocarbon (PAH) compounds JY-1-Cl and JY-2-Cl consisting of rigidified aryl ketones and amine are designed and synthesized under mild conditions through nucleophilic chlorination intermediated by an electron donor-acceptor complex. Among them, as a result of the strong π–π interactions induced by chlorine atoms, JY-2-Cl exhibits bright monomer and dimer emissions with dual thermally activated delayed fluorescence (TADF) characters. Notably, compared with the non-chlorinated compounds, a high photoluminescence quantum yield is maintained after introducing multiple chlorine atoms into JY-2-Cl . The first dual-TADF organic light-emitting diodes are also successfully fabricated with maximum external quantum efficiency as high as 29.1 % by employing JY-2-Cl as emitter. This work presents a new paradigm and synthesis of polychlorinated amine-carbonyl PAHs and demonstrates the great potential of the chlorinated materials for luminescent applications. 相似文献
813.
Hai-Jie Wang Prof. Dr. Yuan Liu Baoqiu Yu Shi-Quan Song Prof. Dr. You-Xuan Zheng Dr. Kanglei Liu Prof. Dr. Pangkuan Chen Prof. Dr. Hailong Wang Prof. Dr. Jianzhuang Jiang Prof. Dr. Tian-Yi Li 《Angewandte Chemie (International ed. in English)》2023,62(7):e202217195
Thermally activated delayed fluorescence (TADF) from linear two-coordinate coinage metal complexes is sensitive to the geometric arrangement of the ligands. Herein we realize the tuning of configuration from coplanar to orthogonal gradually by variation of substituents. In a complex with confined twist configuration, its blue emission peaking at 458 nm presents a high ΦPL of 0.74 and a short τTADF of 1.9 μs, which indicates a fast enough kr,TADF of 3.9×105 s−1 and a depressed knr of 1.4×105 s−1. Such outstanding luminescent properties are attributed to the proper overlap of HOMO and LUMO on CuI d orbitals that guarantees not only small ΔEST but also sufficient transition oscillator strength for fast . Vacuum-deposited blue OLEDs with either doped or host-free emissive layer present external quantum efficiencies over 20 % and 10 %, respectively, demonstrating the practicality of the configurationally confined strategy for efficient linear CuI TADF emitters. 相似文献