215-64-5Relevant articles and documents
Modulated emission from dark triplet excitons in aza-acene compounds: fluorescence versus phosphorescence
Chen, Jianwei,Chen, Yi,Wu, Yishi,Wang, Xuedong,Yu, Zhenyi,Xiao, Lu,Liu, Yanping,Tian, He,Yao, Jiannian,Fu, Hongbing
, p. 1864 - 1871 (2017)
In the field of organic light-emitting diodes (OLEDs), research interests focus on making the optically dark triplet excitons shine in order to increase the electro-optic conversion efficiency of devices. In this work, two kinds of phenazine compounds, i.e. dibenzo[a,c]phenazine (DBP) and tribenzo[a,c,i]phenazine (TBP), were synthesized and used as model compounds to regulate the emission efficiency of the dark triplet excitons by chemical modification. Charge-transfer induced ultrafast intersystem crossing (CT-ISC) with a time constant of ～1 ps was observed for these two phenazine derivatives upon photoexcitation with a high triplet yield of 77.1% for DBP and 58.7% for TBP. The triplet excited states of DBP can produce ultra-long phosphorescence with lifetime as long as 318 ms at 77 K. The quantum yield for phosphorescence (ΦP) is determined to be 8.45%. In sharp contrast, the triplet-excited 3TBP* undergoes an efficient reverse intersystem crossing (RISC) process, resulting in bright delayed fluorescence emission with negligible phosphorescence. A controllable luminescence behavior from the triplet states between fluorescence and phosphorescence in phenazine derivatives is demonstrated. Theoretical calculations reveal that the structure-dependent triplet evolution is due to the charge-transfer induced energy level alignment within these compounds. Our results may have potential applications in the design of OLEDs and high triplet yield pure organic materials.
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Gates,Newhall
, p. 2261 (1948)
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A general method for the synthesis of structurally diverse quinoxalines and pyrido-pyrazine derivatives using camphor sulfonic acid as an efficient organo-catalyst at room temperature
Kaur, Gurpreet,Singh, Arvind,Kaur, Navdeep,Banerjee, Bubun
, p. 1121 - 1131 (2021)
A mild, convenient, eco-friendly, general and practical approach has been developed for the synthesis of a series of structurally diverse quinoxaline derivatives via the condensation reactions of various 1,2-diaminobenzene derivatives and 1,2-dicarbonyls
Ring Closure of Heterocyclic Systems by Potassium-Graphite Intercalat - C8K
Tamarkin, Dov,Cohen, Yoram,Rabinovitz, Mordecai
, p. 196 - 197 (1987)
Potassium-graphite intercalate C8K is the reagent of choice for the ring closure of the dianions of 2,3-diarylquinoxalines derivatives 1-3 to the dianions of dibenzophenazine derivatives 4-6 in high yields and high degree of purity.This process appears to occur via a thermal electrocyclic process of the dianions.
Green Hydrothermal Synthesis of Fluorescent 2,3-Diarylquinoxalines and Large-Scale Computational Comparison to Existing Alternatives
Amaya-García, Fabián,Caldera, Michael,Koren, Anna,Kubicek, Stefan,Menche, J?rg,Unterlass, Miriam M.
, p. 1853 - 1863 (2021/04/02)
Here, the hydrothermal synthesis (HTS) of 2,3-diarylquinoxalines from 1,2-diketones and o-phenylendiamines (o-PDAs) was achieved. The synthesis is simple, fast, and generates high yields, without requiring any organic solvents, strong acids or toxic catalysts. Reaction times down to 90 % in all cases). Moreover, it was shown that HTS has high compatibility: (i) hydrochlorides, a standard commercial form of amines, could be used directly as combined amine source and acidic catalyst, and (ii) Boc-diprotected o-PDA could be directly employed as substrate that underwent HT deprotection. A systematic large-scale computational comparison of all reported syntheses of the presented quinoxalines from the same starting compounds showed that this method is more environmentally friendly and less toxic than all existing methods and revealed generic synthetic routes for improving reaction yields. Finally, the application of the synthesized compounds as fluorescent dyes for cell staining was explored.
BSA-encapsulated cyclometalated iridium complexes as nano-photosensitizers for photodynamic therapy of tumor cells
Xu, Yao,Wang, Xiang,Song, Kang,Du, Jun,Liu, Jinliang,Miao, Yuqing,Li, Yuhao
, p. 15323 - 15331 (2021/05/19)
Photodynamic therapy is a promising treatment method. The development of suitable photosensitizers can improve therapeutic efficacy. Herein, we report three iridium complexes (Ir1, Ir2, and Ir3), and encapsulate them within bovine serum albumin (BSA) to f
