- Synthesis of novel fluorene-functionalised nanoporous silica and its luminescence behaviour in acidic media
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Fluorene-functionalised nanoporous silica (FL-NH2-SBA-15) was prepared using the post-synthesis grafting method of SBA-15. The material thus obtained was characterised by means of small- and wide-angle X-ray diffraction, nitrogen adsorption-desorption, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, and elemental analysis. The results showed that the organised structure is preserved after the post-grafting procedure. Surface area and pore-size decreased by attaching functional groups to the pore surface. In addition, the pore volume was reduced with functionalisation. The amount of fluorene grafted onto the surface of SBA-15 was 0.55 mmol with a yield of approximately 46 %. The emission spectra of FL-NH2-SBA-15 in acidic media were studied and are discussed in detail. The structural change between FL-NH2-SBA-15 and the protonated form might be an effective candidate for acid-dependent molecular-sensor models for advanced application in molecular sensors in the future.
- Yadavi, Marzieh,Badiei, Alireza,Ziarani, Ghodsi Mohammadi,Abbasi, Alireza
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- C-9 fluorenyl substituted anthracenes: A promising new family of blue luminescent materials
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Syntheses, optical, and electrochemical properties of novel C-9 fluorenyl substituted anthracenes linked by a tetrahedral sp3-hybridized carbon atom are reported for blue light emitting materials. Remarkably, an unoptimized organic light-emitting diode based on 1-fold fluorene-functionalized anthracene 3 exhibits a radiance of 4100 cd/m2 at 12 V and a maximum EL efficiency of 1.36 cd/A with color purity CIE x, y (0.157, 0.082), which is very close to the National Television System Committee standard blue.
- Wang, Jing,Wan, Wen,Jiang, Haizhen,Gao, Yan,Jiang, Xueyin,Lin, Huaping,Zhao, Weiming,Hao, Jian
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- Design and synthesis of 9H-fluorenone based 1,2,3-triazole analogues as Mycobacterium tuberculosis InhA inhibitors
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We prepared fifty various 9H-fluorenone based 1,2,3-triazole analogues varied with NH, –S–, and –SO2– groups using click chemistry. The target compounds were characterized by routine analytical techniques, 1H, 13CNMR, mass, elemental, single-crystal XRD (8a) and screened for in vitro antitubercular activity against Mycobacterium tuberculosis (MTB) H37Rv strain and two “wild” strains Spec. 210 and Spec. 192 and MIC50 was determined. Further, the compounds were evaluated for MTB InhA inhibition study as well. The final analogues exhibited minimum inhibitory concentration (MIC) ranging from 52.35 to >295?μm. Among the –NH– analogues, one compound 5p (MIC 58.34?μm), among –S– containing analogues four compounds 8e (MIC 66.94?μm), 8f (MIC 74.20?μm), 8g (MIC 57.55?μm), and 8q (MIC 56.11?μm), among –SO2– containing compounds one compound 10p (MIC 52.35?μm) showed less than MTB MIC 74.20?μm: Compound 4-(((9H-fluoren-9-yl)sulfonyl)methyl)-1-(3,4,5-trimethoxyphenyl)-1H-1,2,3-triazole (10p) was found to be the most active compound with 73% InhA inhibition at 50?μm; it inhibited MTB with MIC 52.35?μm. Further, 10f and 10p were docked to crystal structure of InhA to know binding interaction pattern. Most active compounds were found to be non-cytotoxic against HEK 293 cell lines at 50?μm.
- Suresh, Amaroju,Srinivasarao, Singireddi,Agnieszka, Napiórkowska,Ewa, Augustynowicz-Kope?,Alvala, Mallika,Lherbet, Christian,Chandra Sekhar, Kondapalli Venkata Gowri
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- Turn-off fluorescence chemosensor for iron with Bis(2-aminoethyl)-2-(9- fluorenyl)malonamide functionlized SBA-15
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An bis(2-aminoethyl)-2-(9-fluorenyl)malonamide as fluorophore ligand was immobilized onto mesoporous silica type SBA-15 via post synthesis grafting. The obtained material was characterized by small and wide angle X-ray diffraction, N2 adsorption-desorption, Fourier transform infrared spectroscopy, Raman spectroscopy and thermogravimetric analysis that indicate the successful immobilization of the ligand on the surface of mesoporous silica. The sensing ability of the obtained material was studied by addition of the cations Fe 3+, Mg2+, Cr3+, Co2+, Ni 2+, Cu2+, Hg2+ and Zn2+ to water suspensions of the assayed solid. Of all the cations tested addition of Fe 3+ ion to a suspension of this material resulted in the largest decrease in the fluorescence intensity. Turn-off photoluminescence of this material was remarkably observed for iron ions in comparing of the other cations. A good linearity between the fluorescence intensity of this material and the concentration of Fe3+ ion is constructed, which enables it as a fluorescence chemosensor for detecting the Fe3+ ion with a suitable detection limit of 1.35∈×∈10-5. It can be introduced as a novel fluorescent sensor in aqueous solution for a lot of practical applications in chemical, environmental and biological systems.
- Yadavi, Marzieh,Badiei, Alireza
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- A New Approach to Sensing H+ Using SBA-15 Grafted with Fluorene di-ammonium Groups and Theoretical study
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Fluorene-di-ammonium-functionalized mesoporous silica (FDMS) was prepared through post synthesis grafting method of SBA-15. The obtained material was characterized by means of small and wide angle X-ray diffraction, nitrogen adsorption-desorption, Fourier transform infrared spectroscopy, Raman spec- troscopy, thermo gravimetric analysis and elemental analysis. The results showed that the original structure of SBA-15 is preserved after the post grafting procedure. Surface area, pore size and pore volume de- creased by attaching functional groups to the pore surface. The grafted amount of fluorene on the surface of SBA-15 was 0.50 mmol with yield about 40.6 %. The emission spectra of FDMS was studied in acid me- dia and discussed in details. Computational studies were performed in order to obtain a detailed electronic description of the mechanism of FDMS fluorescence by H+ as well as studying the structure and bonding in the (FDMS)H+. The structural change between FDMS and protonated form can serve as an effective candidate for pH-indicator, and might be used as acid-dependent molecular-sensor models for advanced applications in optical sensors in the future.
- Badiei, Alireza,Yadavi, Marzieh,Shayesteh, Alireza,Jafari, Maryam,Ziarani, Ghodsi Mohammadi
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- Blue fluorescent host compound, and preparation method and device thereof
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The invention relates to a blue fluorescent host compound, and a preparation method and a device thereof. The structural formula of the blue fluorescent host compound is represented by chemical formula 1 shown in the description. Compared with a conventional material, the blue fluorescent host compound of the invention has the advantages of excellent electroluminescent properties, long device service life and proper color coordinates. The organic light-emitting device prepared from the blue fluorescent host compound adopts the novel compound of the chemical formula 1, so that the device becomes the organic light-emitting device with a high efficiency and a long service life. The preparation method of the blue fluorescent host compound has the advantages of simple process and high yield.
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Paragraph 0070-0074
(2020/01/12)
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- Hydrodebromination of allylic and benzylic bromides with water catalyzed by a rhodium porphyrin complex
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Hydrodebromination of allylic and benzylic bromides was successfully achieved by a rhodium porphyrin complex catalyst using water as the hydrogen source without a sacrificial reductant. Mechanistic investigations suggest that bromine atom abstraction via a rhodium porphyrin metalloradical operates to give the rhodium porphyrin alkyl species and the subsequent hydrolysis of the rhodium porphyrin alkyl species to a hydrocarbon product is a key step to harness the hydrogen from water.
- Yang, Wu,Chen, Chen,Chan, Kin Shing
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supporting information
p. 12879 - 12883
(2018/10/02)
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- Carbocation Catalyzed Bromination of Alkyl Arenes, a Chemoselective sp3 vs. sp2 C?H functionalization.
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The versatility of the trityl cation (TrBF4) as a highly efficient Lewis acid organocatalyst is demonstrated in a light induced benzylic brominaion of alkyl-arenes under mild conditions. The reaction was conducted at ambient temperature under common hood light (55 W fluorescent light) with catalyst loadings down to 2.0 mol% using N-bromosuccinimide (NBS) as the brominating agent. The protocol is applicable to an extensive number of substrates to give benzyl bromides in good to excellent yields. In contrast to most previously reported strategies, this protocol does not require any radical initiator or extensive heating. For electron-rich alkyl-arenes, the trityl ion catalyzed bromination could be easily switched between benzylic sp3 C?H functionalization and arene sp2 C?H functionalization by simply alternating the solvent. This chemoselective switch allows for high substrate control and easy preparation of benzyl bromides and bromoarenes, respectively. The chemoselective switch was also applied in a one-pot reaction of 1-methylnaphthalene for direct introduction of both sp3 C?Br and sp2 C?Br functionality. (Figure presented.).
- Ni, Shengjun,El Remaily, Mahmoud Abd El Aleem Ali Ali,Franzén, Johan
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supporting information
p. 4197 - 4204
(2018/09/25)
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- LOW TEMPERATURE RADICAL INITIATOR SYSTEM AND PROCESSES MAKING USE THEREOF
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The present invention refers to a process making use of a radical initiator system comprising peroxy compounds, in particular peroxyketals, in the presence of an acid catalyst to initiate radical processes at low temperature, such as room temperature and below.
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Page/Page column 15-18
(2017/07/14)
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- Regioselective monobromination of aromatics via a halogen bond acceptor-donor interaction of catalytic thioamide and N-bromosuccinimide
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Regioselective monobromination of various aromatics was achieved at room temperature using N-bromosuccinimide and 5 mol% of thioamides in acetonitrile. With thiourea as catalyst, activated aromatics, such as anisole, acetanilide, benzamide and phenol analogues containing electron donating or withdrawing groups, were brominated with high regioselectivity. Room temperature brominations of weakly activated aromatics and deactivated 9-fluorenone were accomplished by 5 mol% thioacetamide, higher substrates concentrations and longer reaction times. A backbonding of the bromine lone pairs with the π*of C[dbnd]S group and a halogen bond between the halogen bond donor bromine and the halogen bond acceptor sulfur of the thioamide are thought to be the principal interactions and cause of N-bromosuccinimide activation.
- Bovonsombat, Pakorn,Teecomegaet, Pattaradra,Kulvaranon, Panisanun,Pandey, Aditi,Chobtumskul, Kittithorn,Tungsirisurp, Sireethorn,Sophanpanichkul, Punyanuch,Losuwanakul, Satreerat,Soimaneewan, Dechathon,Kanjanwongpaisan, Patcharida,Siricharoensang, Pornpawit,Choosakoonkriang, Sirirat
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p. 6564 - 6572
(2017/10/17)
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- Acid-Catalyzed Activation of Peroxyketals: Tunable Radical Initiation at Ambient Temperature and below
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This study details how peroxyketals, commercially available thermal initiators, and structurally related peroxides are activated in the presence of an acid catalyst to generate radicals at room temperature and below. This simple combination of two substrates was shown to efficiently initiate a variety of radical processes. This phenomenon is rationalized by the acid-catalyzed in situ formation of highly unstable alkenyl peroxides which readily decompose into initiating radical species.
- Schweitzer-Chaput, Bertrand,Boess, Esther,Klussmann, Martin
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supporting information
p. 4944 - 4947
(2016/10/18)
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- Tribromoisocyanuric acid as a green reagent for benzylic bromination of alkylarenes
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The reaction of diverse alkylarenes with tribromoisocyanuric acid (0.34 mol equiv) in reflux EtOAc in the absence of any catalysts or light irradiation produced the corresponding benzyl bromides in 53-88% yield.
- De Almeida, Leonardo S.,Esteves, Pierre M.,De Mattos, Marcio C.S.
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p. 6843 - 6845
(2015/11/27)
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- Novel blue luminescent materials for organic light-emitting diodes based on C9-fluorenyl anthracenes
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A series of twisted fluorenyl anthracenes linked by a rigid sp 3-hybridized carbon atom, containing an end-capping aryl substituent at either the C2-position of fluorene or at the C10-position of anthracene, have been synthesized and characterized. These materials exhibited good thermal stabilities and amorphous properties. Theoretical calculations and X-ray diffraction studies revealed that the six blue emitters possess non-coplanar structures to suppress intermolecular interactions. The relationship between the chemical structures with different end-capping groups and the electroluminescent properties has been investigated. Organic light-emitting diodes utilizing 9-(2-phenyl-9H-fluoren-9-yl) anthracene as the emitter exhibited deep-blue emissions CIE x, y (0.166, 0.153) with a current efficiency of 1.47 cd/A, external quantum efficiency of 1.84% at 20 mA/cm2 and a maximum brightness of 3013 cd/m2 at 11 V. It was found that the introduction of the aryl substituents to the C2 position of fluorene could improve the performance of OLEDs based on C9-fluorenyl anthracenes.
- Wan, Wen,Du, Heliang,Wang, Jing,Le, Yuping,Jiang, Haizhen,Chen, Hua,Zhu, Shizheng,Hao, Jian
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p. 642 - 652
(2013/03/13)
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- Microwave-assisted benzyl mono- and dibromination in diethyl carbonate as environmentally friendly alternative to radical bromination in carbon tetrachloride
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An environmentally friendly benzyl mono- and di-bromination synthetic procedure was developed that is superior to the classic carbon tetrachloride bromination procedure in both reaction time and isolated yield. This new reaction was performed in diethyl carbonate as reaction media using microwave instead of conventional heating. Both the solvent and the brominating reagent N-bromosuccinimide (prepared from succinimide obtained from the reaction mixture) are recyclable. Practically, the preparation of our target compounds was completed in less than two hours. The Royal Society of Chemistry.
- Pingali, Subramanya R. K.,Upadhyay, Sunil K.,Jursic, Branko S
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experimental part
p. 928 - 933
(2011/05/15)
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- Benzimidazolium bromochromate - a new reagent for bromination and oxidation
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The new reagent, benzimidazolium bromochromate (BIBC), apart from being efficient as an oxidant for alcohols, also functions as a good brominating agent for aromatic compounds.
- Oezguen, B.,Degirmenbasi, N.
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p. 763 - 766
(2007/10/03)
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- A Convenient One-Pot Synthesis of Aralkyl Bromides and Iodides by Reductive Halogenation of Aromatic Carbonyl Compounds
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Aromatic aldehydes, ketones, carboxylic acids, and esters are converted in high yields to the corresponding aralkyl bromides or iodides by a one-pot procedure which consist of quenching the complex formed from lithium aluminum hydride and the starting material with hydrogen bromide or iodide.
- Bilger, Christine,Royer, Rene,Demerseman, Pierre
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p. 902 - 904
(2007/10/02)
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- Pyridinium Bromochromate - A New Reagent for Bromination and Oxidation
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The new reagent, pyridinium bromochromate (PBC), apart from being efficient as an oxidant for alcohols, also functions as a good brominating agent for aromatic compounds.
- Narayanan, N.,Balasubramanian, T. R.
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p. 228 - 229
(2007/10/02)
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- NOVEL BROMINATION REAGENTS. HEXABROMOCYCLOPENTADIENE: BROMINATION OF ACTIVATED SATURATED SITES
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Hexabromocyclopentadiene (HBC) readily brominates α-keto and benzylic sites, apparently by bromonium ion transfer.
- Magen, Shulamit,Oren, Jakob,Fuchs, Benzion
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p. 3369 - 3372
(2007/10/02)
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