1898-74-4Relevant academic research and scientific papers
Expanding the hole delocalization range in excited molecules for stable organic light-emitting diodes employing thermally activated delayed fluorescence
Ai, Qi,Cao, Fangyi,Deng, Chao,Liu, Zhang,Su, Liwu,Tsuboi, Taiju,Wang, Chao,Wang, Dan,Zhang, Qisheng,Zheng, Xinyuan,Zhu, Yunhui
, p. 10021 - 10030 (2020)
Metal-free, thermally activated delayed fluorescent (TADF) emitters have emerged as a promising new generation of organic light-emitting diode (OLED) materials. Donor-acceptor (D-A) structures are widely used in TADF molecular design to ensure a small energy splitting between the singlet and triplet excitons. Here, a series of efficient bluish-green TADF emitters are constructed using one or two phenyltriazine acceptors and one tercarbazole, bicarbazole or indolo[2,3-b]carbazole donor through an ortho-linkage. The impact of the D/A ratio on the photoluminescence and electroluminescence stability of these emitters in doped films is thoroughly investigated. According to the two-exciton dynamics and the degradation products, device degradation is deduced to be a result of electrophilic substitution between two charge-transfer excitons. Within a limited molecular weight range, increasing the number of acceptor moieties leads to a decrease in the hole delocalization range in the excited state, which facilitates the substitution reaction. Based on an optimized device structure, the device containing an emitter with bulk a tercarbazole donor achieves a long half-life of 1512 hours with an initial luminescence of 1000 cd m-2. Our findings reveal a possible mechanism for exciton-exciton and exciton-polaron annihilation-induced device degradation and provide new approaches for achieving stable OLEDs employing TADF.
Synthesis of 1,2-dihydro-1,3,5-triazine derivativesviaCu(ii)-catalyzed C(sp3)-H activation ofN,N-dimethylethanolamine with amidines
Chen, Rener,Ma, Renchao,Ma, Yongmin,Wang, Lei,Wang, Zhiming,Yan, Min
supporting information, p. 10946 - 10949 (2020/10/02)
1,2-Dihydro-1,3,5-triazines and symmetrical 1,3,5-triazines were obtained in up to 81% yields from amidines andN,N-dimethylethanolamine catalyzed by CuCl2. The reaction involves three C-N bond formations during the oxidative annulation process
New Strategy for the Synthesis of Heterocycles via Copper-Catalyzed Oxidative Decarboxylative Amination of Glyoxylic Acid
Niu, Bin,Li, Shaoqing,Cui, Chang,Yan, Yizhe,Tang, Lin,Wang, Jianyong
supporting information, p. 7800 - 7803 (2019/11/28)
A copper-catalyzed oxidative decarboxylative amination of glyoxylic acid with substrates having two nitrogen-nucleophilic sites was first demonstrated. Using this novel approach, 1,3,5-triazines, quinazolinones and quinazolines were obtained in up to 93 % yields. Notably, glyoxylic acid was employed as the C1 synthon for heterocycles. This strategy enriches the application of glyoxylic acid for the synthesis of valuable heterocycles.
Transition metal-free C-F/C-Cl/C-C cleavage of ClCF2COONa for the synthesis of heterocycles
Yan, Yizhe,Cui, Chang,Wang, Jianyong,Li, Shaoqing,Tang, Lin,Liu, Yanqi
supporting information, p. 8071 - 8074 (2019/09/19)
A transition metal-free and external oxidant-free annulation of substrates having two nitrogen-nucleophilic sites with ClCF2COONa was demonstrated, affording a series of 1,3,5-triazines and quinazolinones in up to 96% yields. Notably, ClCF
Transition metal-free assembly of 1,3,5-triazines using ethyl bromodifluoroacetate as C1 source
Yu, Xiaoxia,Zhou, Yao,Ma, Xingxing,Song, Qiuling
supporting information, p. 8079 - 8082 (2019/07/15)
An efficient transition metal-free annulation of amidine with ethyl bromodifluoroacetate to access 2,4-disubstituted-1,3,5-triazines is firstly presented. The desired symmetric and unsymmetric 2,4-disubstituted-1,3,5-triazines were obtained in decent yields via multiple C-N bond formation, in which ethyl bromodifluoroacetate is harnessed as a unique C1 synthon via quadruple cleavage. This reaction is transition metal-free, oxidant-free and simple in operation, and only lowly toxic inorganic wastes are generated.
A multi-substituted 1, 3, 5 - triazine (by machine translation)
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Paragraph 0019-0042, (2019/06/07)
The present invention discloses a multi-substituted 1, 3, 5 - triazine, in particular to in order to replace the carboxamidine hydrochloride as a reaction substrate, two fluorine chlorine sodium acetate as a carbon synthons, in the equivalent function of
Dichloromethane as C1 Building Block: Synthesis of 2,4-Disubstitued 1,3,5-Triazines via Copper-Catalyzed Aerobic C?H/C?Cl Cleavage
Yan, Yizhe,Cui, Chang,Wang, Jianyong,Li, Shaoqing,Liu, Yanqi
supporting information, p. 1166 - 1170 (2019/01/30)
A copper-catalyzed aerobic oxidative annulation of amidines with dichloromethane was first demonstrated. Using this novel approach, 16 examples of symmetrical 2,4-disubstitued 1,3,5-triazines and 7 examples of unsymmetrical ones were obtained with up to 82% yields. Moreover, a D-labeling experiment proved that dichloromethane was employed as the C1 building block and solvent. A primary kinetic isotope effect revealed that the C?H cleavage of dichloromethane might be a rate-determining step. This protocol provides a novel strategy for the synthesis of heterocycles. (Figure presented.).
An I2-mediated aerobic oxidative annulation of amidines with tertiary amines: Via C-H amination/C-N cleavage for the synthesis of 2,4-disubstituted 1,3,5-triazines
Yan, Yizhe,Li, Zheng,Cui, Chang,Li, Hongyi,Shi, Miaomiao,Liu, Yanqi
supporting information, p. 2629 - 2633 (2018/04/27)
An iodine-mediated formal oxidative cycloaddition of amidines with tertiary amines was first demonstrated in air. Both symmetrical and unsymmetrical 2,4-disubstituted 1,3,5-triazines were obtained in up to 85% yields. It is noted that a tertiary amine was employed as a one carbon synthon of 1,3,5-triazines and two C-N bonds were formed in one pot. Control experiments revealed that the reaction underwent a radical pathway promoted by I+. The method is transition-metal-free, peroxide-free, and operationally simple to implement with a wide scope of substrates.
Silver-catalyzed [3+2+1] annulation of aryl amidines with benzyl isocyanide
Lu, Xiaodong,Xin, Xiaoyi,Wan, Boshun
, p. 361 - 364 (2018/01/08)
A silver-catalyzed [3+2+1] annulation of amidines with benzyl isocyanide toward 2,4-diaryl-1,3,5-triazines was developed. A variety of symmetrical and unsymmetrical products were obtained in moderate to good yields. This work also features an oxidant-free approach to 2,4-disubstituted triazines.
