- Poly(dihydroxybenzoquinone): Its high-density and robust charge storage capability in rechargeable acidic polymer-air batteries
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A rechargeable acidic polymer-air battery was firstly fabricated with poly(2,5-dihydroxy-1,4-benzoquinone-3,6-methylene) (PDBM) as the anode, the conventional Pt/C cathode catalyst, and acidic aqueous electrolyte (pH 1). This battery yielded a high discharging capacity of 349 mA h gpolymer-1 with a long-lifetime of >500 cycles and high rate capabilities (up to 10C).
- Furukawa, Shuhei,Murao, Saki,Nishide, Hiroyuki,Oka, Kouki,Oka, Tatsuya,Oyaizu, Kenichi
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- A turn-on fluorescent chemosensor selectively detects cyanide in pure water and food sample
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A turn-on fluorescent chemosensor (H-1) for cyanide anions based on dihydroxy phenazine was designed and synthesised. The sensor H-1 exhibits high sensitivity and good selectivity for cyanide in pure water. The CN- response mechanism involves a hydrogen bonding and deprotonation process in the sensor, which induced prominent fluorescence enhancement. The detection limit of the sensor toward CN- is 5.65 × 10-7 M, and other anions had nearly no influence on the probing behavior. In addition, test strips based on the sensor were fabricated, which also exhibit a good selectivity to CN- in water. Notably, this sensor was successfully applied to detect CN- in food samples, which proves a very simple and selective platform for on-site monitoring of CN- in agriculture samples.
- Wei, Tai-Bao,Li, Wen-Ting,Li, Qiao,Su, Jun-Xia,Qu, Wen-Juan,Lin, Qi,Yao, Hong,Zhang, You-Ming
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- A Strategic High Yield Synthesis of 2,5-Dihydroxy-1,4-benzoquinone Based MOFs
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Metal organic frameworks (MOFs) of the type NBu4M(DHBQ)1.5 (M = Ni2+, Fe2+, and Co2+ DHBQ = 2,5-dihydroxy-1,4-benzoquinone) were prepared with improved yield up to 100% via a simple benchtop aqueous addition reaction. For the first time, the crystalline phase of this formula polymer was synthesized without in situ generation of the DHBQ ligand from 2, 5-diamino-1,4-benzoquinone (DABQ). Powder X-ray diffraction and elemental analysis confirm the crystalline phase and composition of products. Infrared and electron dispersive spectroscopy further confirm that the materials are homologous to the reported single crystalline polymers. The present MOF synthesis can be extended to halide-substituted ligands, i.e., 3,6-dichloro-2,5-dihydroxy-1,4-benzoquinone (chloranilic acid, CAN) and 3,6-difluoro-2,5-dihydroxy-1,4-benzoquinone (fluoranilic acid, FAN).
- Nielson, Kevin V.,Zhang, Liping,Zhang, Qiang,Liu, T. Leo
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supporting information
p. 10756 - 10760
(2019/08/26)
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- The impact of an isoreticular expansion strategy on the performance of iodine catalysts supported in multivariate zirconium and aluminum metal-organic frameworks
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Iodine functionalized variants of DUT-5 (Al) and UiO-67 (Zr) were prepared as expanded-pore analogues of MIL-53 (Al) and UiO-67 (Zr). They were prepared using a combination of multivariate and isorecticular expansion strategies. Multivariate MOFs with a 25% iodine-containing linker was chosen to achieve an ideal balance between a high density of catalytic sites and sufficient space for efficient diffusion. Changes to the oxidation potential of the catalyst as a result of the pore-expansion strategy led to a decrease in activity with electron rich substrates. On the other hand, these larger frameworks proved to be more efficient catalysts for substrates with higher oxidation potentials. Recyclability tests for these larger MOFs showed sustained catalytic activity over multiple recycles.
- Tahmouresilerd, Babak,Moody, Michael,Agogo, Louis,Cozzolino, Anthony F.
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supporting information
p. 6445 - 6454
(2019/05/24)
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- Degradation of the Cellulosic Key Chromophore 5,8-Dihydroxy-[1,4]-naphthoquinone by Hydrogen Peroxide under Alkaline Conditions
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5,8-Dihydroxy-[1,4]-naphthoquinone (DHNQ) is one of the key chromophores in cellulosic materials. Its almost ubiquitous presence in cellulosic materials makes it a target molecule of the pulp and paper industry's bleaching efforts. In the presented study, DHNQ was treated with hydrogen peroxide under alkaline conditions at pH 10, resembling the conditions of industrial hydrogen peroxide bleaching (P stage). The reaction mechanism, reaction intermediates, and final degradation products were analyzed by UV/vis, NMR, GC-MS, and EPR. The degradation reaction yielded C1-C4 carboxylic acids as the final products. Highly relevant for pulp bleaching are the findings on intermediates of the reaction, as two of them, 2,5-dihydroxy-[1,4]-benzoquinone (DHBQ) and 1,4,5,8-naphthalenetetrone, are potent chromophores themselves. While DHBQ is one of the three key cellulosic chromophores and its degradation by H2O2 is well-established, the second intermediate, 1,4,5,8-naphthalenetetrone, is reported for the first time in the context of cellulose discoloration.
- Zwirchmayr, Nele Sophie,Hosoya, Takashi,Henniges, Ute,Gille, Lars,Bacher, Markus,Furtmüller, Paul,Rosenau, Thomas
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p. 11558 - 11565
(2017/11/10)
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- Synthesis of a focused chemical library based on derivatives of embelin, a natural product with proapoptotic and anticancer properties
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The synthesis of new derivatives of embelin, a natural inhibitor of X-linked inhibitor of apoptosis protein (XIAP) is described. The design of these new molecules involved introduction of aromatic groups directly linked to the benzoquinone core. To allow a large flexibility in the nature and the length of the added chain, the strategy involves first aSuzuki-Miyaura reaction with functionalized aromatics, yielding a first generation of molecules. Then, by appropriate use of the functional groups, a second generation of representative embelin derivatives was prepared.
- Viault, Guillaume,Gree, Danielle,Das, Saibal,Yadav, Jhillu Singh,Gree, Rene
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experimental part
p. 1233 - 1241
(2011/04/17)
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- Simple cyclodextrin aldehydes as excellent artificial oxidases
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Cyclodextrin based oxidases, with a ketone as functional group are well known as good artificial enzyme mimics (Fenger et al. Org Biomol Chem 7:933-943; Marinescu and Bols Angew Chem Int Ed 45:4590-4593; Bjerre et al. Eur J Org Chem 704-710; Marinescu et al. J Am Chem Soc 127:17578-17579). We here report a series of modified cyclodextrins, having aldehydes as functional groups. The aldehyde based artificial enzymes have, in most cases, better catalysis than the ketones, because of their powerful covalent binding of hydrogen peroxide. Among the modified cyclodextrins studied are mono and di aldehydes on the 6 positions, with or without methylated hydroxyl groups. The aldehyde functionality was also introduced close to the secondary side, by attaching ethoxy-2-al or propoxy-3-al to the 2 position. The modified cyclodextrins showed excellent enzymatic activity towards oxidation of different aminophenols, and 4-methoxy benzyl alcohol with hydrogen peroxide as a stoichiometric oxidant. Rate enhancements up to 4,600 were achieved for oxidation of 4-methoxy benzyl alcohol, where as oxidation of amines gave rate enhancements up to 3,400. The artificial oxidases catalyses oxidations under enzymatic conditions (water, pH 7, 25 °C), following Michaelis-Menten kinetics. To confirm the enzyme activity, inhibition studies with sodium naphthalene-2-sulfonate were carried out. These studies showed competitive inhibition of the enzymes, verifying the cyclodextrins enzyme like character.
- Fenger, Thomas Hauch,Bols, Mikael
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experimental part
p. 397 - 402
(2012/03/11)
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- Nanoscale molecular rods with a new building block for solubility enhancement
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(Chemical Equation Presented) A new building block bearing a [1,3]dioxolo[4,5-f][1,3]benzodioxole core was developed to enhance the solubility of molecular rods by lateral alkyl chains. On incorporation in molecular rods with oligospiroketal structure, the straight geometry is retained, which was concluded from the X-ray crystal structure analysis of one of the rods. The determination of the solubility of a collection of rods bearing this building block revealed that already a butyl group efficiently hinders the aggregation of the rods and consequently causes a considerable enhancement of the solubility. Piperidine rings are located at the ends of the rods, which offer the opportunity for versatile functionalization. Thus, an N,N′-bis(azidoacetyl)-functionalized rod was prepared, which could serve as rigid linkage, initiated by a "Click" reaction.
- Wessig, Pablo,Moellnitz, Kristian
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p. 4452 - 4457
(2008/09/21)
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- Light-induced formation of 2,5-dihydroxy-p-benzoquinone from hydroquinone in photoirradiated silver-loaded zirconium phosphate suspension
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Silver-loaded zirconium phosphate [Ag1-xHxZr2(PO4)3] has shown photocatalytic activity concerning the generation of OH? and the hydroxylation of hydroquinone (HQ) to 2,5-dihydroxy-p-benzoquinone (DHQH2). HQ was initially oxidized to p-benzoquinone (BQ) by Ag+ on the surface of Ag1-xHxZr2(PO4)3 in the dark and by photogenerated OH? during visible-light irradiation. As an intermediate, a semiquinone radical BQH? was detected by EPR measurements in both cases. Furthermore, under visible-light irradiation, DHQH2 was identified by its absorption spectrum and thin layer chromatography. The amount of DHQH2 increased and BQ decreased with irradiation time. The total amount of BQ and DHQH2 under visible-light irradiation agreed with that of BQ in the dark. Consequently, DHQH2 appeared to form from BQH? generated by the oxidation of HQ and the reduction of BQ by photogenerated e-. From the XPS and FT-Raman technique analyses, it was found that the addition of the photogenerated OH? to BQH? occurred at the surface of Ag1-xHxZr2(PO4)3. This indicated that both the OH? and HBQ? were stabilized on the surface of Ag1-xHxZr2(PO4)3.
- Miyoshi, Hirokazu,Kourai, Hiroki,Maeda, Takuya
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p. 283 - 287
(2007/10/03)
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- Method for dyeing keratinous fibres using a monohydroxyindole or dihydroxyindole and a non-oxidizing aromatic carbonyl derivative and dyeing agent
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The present invention relates to a method for dyeing keratinous fibers, characterized in that the following are applied to the fibers: a) a composition (A) containing, in a medium appropriate for dyeing, at least one monohydroxyindole or dihydroxyindole, this application being preceded or followed by the application of b) a composition (B) containing, in a medium appropriate for dyeing, at least one aromatic carbonyl derivative chosen from hydroxyacetophenones, hydroxybenzophenones, 2-hydroxy-1,4-benzoquinones, hydroxy-1,4-naphthoquinones,amino-1,4-naphthoquinones,hydroxy-9,10-anthraquinones and amino-9,10-anthraquinones. It also relates to the dyeing agents for carrying it out.
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