23000-28-4Relevant academic research and scientific papers
Brightness enhanced blue to green light color conversion copolymer, alkylfluorene-benzothiadiazole-benzylidenylfluorene
Oh, Dong Won,Lee, Woo Bung,Choi, Heung Jin,Kim, Hong Tak,Lee, Hyeong-Rag,Lee, Sung-Youp
, p. 91 - 98 (2017)
A new photoluminescent (PL) polymer, alkylfluorene-benzothiadiazole-benzylidenylfluorene copolymer, was synthesized by a Suzuki coupling reaction, and its optical properties and applicability as a color conversion material were studied. The synthesized PL polymer showed good thermal stability and superior color conversion ability which converts blue light into green. A color conversion film was fabricated using a screen printing method and its optical properties were analyzed after placing the fabricated color-conversion film on a blue light emission device. The measured brightness was 1120 cd/m2, which was approximately 346% higher than that measured for the device without a color-conversion film (251 cd/m2).
Fluorene based fluorescent and colorimetric sensors for ultrasensitive detection of nitroaromatics in aqueous medium
Tahir Waseem, Muhammad,Muhammad Junaid, Hafiz,Gul, Hira,Ali Khan, Zulfiqar,Yu, Cong,Anjum Shahzad, Sohail
, (2021/11/22)
New butterfly-shaped π-extended sensors 4 and 5 were synthesized through the Knoevenagel condensation and the Suzuki-Miyaura coupling reaction. Sensors were employed for sensitive detection of nitroaromatics. Among nitroaromatic compounds (NACs), sensors 4 and 5 exhibited ultrasensitive fluorescence quenching response to picric acid (PA) with quenching efficiency >45 and >260 folds and limit of detection (LOD) 22.0 and 0.23 ppt (parts per trillion), respectively. This ultra-sensitivity was contributed by FRET and IFE processes. Selective interaction of sensors with PA was evaluated by fluorescence, UV–Vis., 1H NMR titration, dynamic light scattering (DLS), and density functional theory (DFT) calculations. These sensors were successfully employed for detection of picric acid in real water samples. Interestingly, sensors 4 and 5 showed selective colorimetric recognition of picric acid. Moreover, sensors’ coated test strips were fabricated for an immediate naked eye detection of PA that demonstrated rapidity, simplicity, and convenience for on-site detection of PA. Robust sensitivity for PA illustrated that these sensors can be employed in the development of new detection tools for PA analysis in real samples.
Intermolecular oxidative Friedel-Crafts reaction triggered ring expansion affording 9,10-diarylphenanthrenes
Jin, Tienan,Yang, Lu,Gridnev, Ilya D.,Terada, Masahiro
supporting information, p. 8920 - 8924 (2020/12/02)
A novel intermolecular tandem oxidative aromatic coupling between arylidene fluorenes and unfunctionalized aromatics mediated by a DDQ/TFA oxidation system has been developed for the construction of 9,10-diary-lphenanthrenes (DAPs). The formation of a benzylic carbocation species possessing a quaternary sp3-carbon center on the fluorene moiety by an intermolecular oxidative Friedel-Crafts reaction of two different arenes successfully triggered the subsequent ring expansion to afford DAPs.
Heterocyclic free radicals. Part 1. 4,5-Diazafluorene derivatives of Koelsch's free radical: an EPR and metal-ion complexation study
Plater, M. John,Kemp, Steven,Lattmann, Eric
, p. 971 - 980 (2007/10/03)
Heteroaromatic precursors to nitrogen substituted derivatives of Koelsch's free radicals have been prepared by the condensation of 4,5-diazafluorene with a fluorenylidene or diazafluorenylidene. These compounds appear coloured and can exist in different tautomeric forms. An improved one pot synthesis of 4,5-diazafluorenone has been developed by the oxidative ring contraction of 1,10-phenanthroline with aqueous potassium permanganate. Aza derivatives of Koelsch's free radical are easily generated by oxidation of the appropriate precursors with K3Fe(CN)6. Treatment of 9-[(9H-4,5-diazafluoren-9-ylidene)phenylmethyl]-9H-fluoren-9-yl radical with CuCl2 in EtOH gives a brown precipitate of a 1:1 radical-ligand complex.
Facile synthesis of 1,2-diaryl- and triarylethenes with supported fluoride bases
Hellwinkel,Goke,Karle
, p. 973 - 978 (2007/10/02)
Differently substituted arenecarbaldehydes, mainly benzaldehydes, can be very efficiently condensed with a wide variety of methylbenzenes having an electron-withdrawing group in the para-position, as well as with fluorenes, xanthene, cyclopentadienes and indenes by using a standardized KF- or CsF-Al2O3 base system in dimethylformamide.
Studies on Betaine Decomposition of Arsonium Ylides
Tewari, R. S.,Suri, S. K.,Gupta, K. C.
, p. 95 - 98 (2007/10/02)
A systematic study on the nature of decomposition of betaine formed by nucleophilic attack of semistabilized arsonium ylides on thiocarbonyl substrates has been carried out.A series of substituted benzylidenetriphenylarsenanes have been generated from their corresponding salts and condensed with few cyclic thioketones to yield exocyclic olefins as exclusive products.The non-availability of thioepoxides indicates that the mode of decomposition of such type of betaines is quite analogous to the betaine formed by phosphonium ylides.The structure of the products have been assigned by IR and NMR spectral studies. - Keywords: Betaine, Arsonium Ylides
