25603-67-2Relevant articles and documents
The first ESR observation of radical species in subcritical water
Kobiro, Kazuya,Matsura, Masahiko,Kojima, Hiroyuki,Nakahara, Koichi
, p. 807 - 810 (2009)
Triphenylmethanol was treated in subcritical and supercritical water. A radical species, triphenylmethyl radical, was directly generated from triphenylmethanol in subcritical and supercritical water without using any radical initiator. The radical formati
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Bottaro
, p. 990 (1978)
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Novel multifunctional fluorene-phenanthroimidazole hybrid materials: Non-doped near-ultraviolet fluorescent emitter and host for green phosphorescent OLEDs
Chi, Hai-Jun,Guan, Hui-Min,Hu, Yong-Xu,Hu, Zhi-Zhi,Li, Xiao,Lv, Yan-Li,Xiao, Guo-Yong,Xie, Dong-Dong,Zhang, Dong-Yu
, (2020/12/07)
Deep-blue-emissive host materials are crucial to achievement of high-performance full-color organic light-emitting diodes (OLEDs), simplifying the manufacturing process and reducing production costs. To develop efficient deep-blue-emissive host materials is still challenging. By incorporating 9,9-diphenylfluorene moiety into phenanthroimidazole via the insulating N1 position of imidazole, two fluorene-phenanthroimidazole hybrid near-ultraviolet-emitting materials FL-PI and FL-BPI were designed and synthesized. The photophysical property, thermal and amorphous ability, electrochemical property and electron structure could be effectively regulated by molecular design strategy. Both FL-PI and FL-BPI exhibited moderate near-ultraviolet emission (0.50/0.63), high triplet energy level (2.58/2.57eV), high thermostability (Td: 371/542 °C; Tg: 134/210 °C) and carrier-transporting nature. Non-doped near-ultraviolet OLEDs adopting FL-BPI emitter showed the maximum efficiencies of 5.4%, 3.8 cd A?1 and 2.8 lm W?1 with the CIE coordinates of (0.15, 0.05). In addition, FL-PI/FL-BPI-hosted green phosphorescent OLEDs demonstrated the maximum efficiencies of 16.3%, 28.8 cd A?1, 21.1 lm W?1 and 21.1%, 75.3 cd A?1, 27.8 lmW?1, respectively. Moreover, the external quantum efficiencies of FL-PI/FL-BPI-hosted green phosphorescent devices remained as high as 16.1% and 21.0% at 1000 cd m?2. This work demonstrates that the strategy for the development of near-ultraviolet high-emissive host materials is feasible.
Mild, Rapid, and Chemoselective Procedure for the Introduction of the 9-Phenyl-9-fluorenyl Protecting Group into Amines, Acids, Alcohols, Sulfonamides, Amides, and Thiols
Soley, Jacob,Taylor, Scott D.
, (2020/02/04)
The 9-phenyl-9-fluorenyl (PhF) group has been used as an Nα protecting group of amino acids and their derivatives mainly as a result of its ability to prevent racemization. However, installing this group using the standard protocol, which employs 9-bromo-9-phenylfluorene/K3PO4/Pb(NO3)2, often takes days and yields can be variable. Here, we demonstrate that the PhF group can be introduced into the amino group of Weinreb's amides and methyl esters of amino acids, as well as into alcohols and carboxylic acids, rapidly and in excellent yields, using 9-chloro-9-phenylfluorene (PhFCl)/N-methylmorpholine (NMM)/AgNO3. Nα-PhF-protected amino acids can be prepared from unprotected α-amino acids, rapidly and often in near quantitative yields, by treatment with N,O-bis(trimethylsilyl)acetamide (BSA) and then PhFCl/NMM/AgNO3. Primary alcohols can be protected with the PhF group in the presence of secondary alcohols in moderate yield. Using PhFCl/AgNO3, a primary alcohol can be protected in good yield in the presence of a primary ammonium salt or a carboxylic acid. Primary sulfonamides and amides can be protected in moderate to good yields using phenylfluorenyl alcohol (PhFOH)/BF3·OEt2/K3PO4, while thiols can be protected in good to excellent yield using PhFOH/BF3·OEt2 even in the presence of a carboxylic acid or primary ammonium group.
