- Intermolecular London Dispersion Interactions of Azobenzene Switches for Tuning Molecular Solar Thermal Energy Storage Systems
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The performance of molecular solar thermal energy storage systems (MOST) depends amongst others on the amount of energy stored. Azobenzenes have been investigated as high-potential materials for MOST applications. In the present study it could be shown that intermolecular attractive London dispersion interactions stabilize the (E)-isomer in bisazobenzene that is linked by different alkyl bridges. Differential scanning calorimetry (DSC) measurements revealed, that this interaction leads to an increased storage energy per azo-unit of more than 3 kcal/mol compared to the parent azobenzene. The origin of this effect has been supported by computation as well as X-ray analysis. In the solid state structure attractive London dispersion interactions between the C?H of the alkyl bridge and the π-system of the azobenzene could be clearly assigned. This concept will be highly useful in designing more effective MOST systems in the future.
- Kunz, Anne,Heindl, Andreas H.,Dreos, Ambra,Wang, Zhihang,Moth-Poulsen, Kasper,Becker, Jonathan,Wegner, Hermann A.
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- High purity, 2, 2-bis (4-aminophenyl) propane and its manufacturing method (by machine translation)
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PROBLEM TO BE SOLVED: To provide new 2,2-bis (4-aminophenyl) propane of high purity, and provide a method of efficiently and easily manufacturing it as powder. SOLUTION: This method of manufacturing 2,2-bis (4-aminophenyl) propane includes: a step (1) of evaporating a component which mainly contains unreacted acetone, extraction solvent and aniline, and whose boiling point is lower than that of 2,2-bis (4-aminophenyl) propane from a reaction liquid obtained by condensing acetone and aniline hydrochloride under the presence of water and then performing alkali treatment; and a step (2) of adding an aromatic hydrocarbon based solvent to it, heating and melting them, and then cooling and crystallizing 2,2-bis (4-aminophenyl) propane. COPYRIGHT: (C)2012,JPO&INPIT
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Paragraph 0025
(2018/11/22)
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- Comparison between SiMe2 and CMe2 spacers as σ-bridges for photoinduced charge transfer
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The potential of dimethylsilylene and isopropylidene σ-spacers as bridges for photoinduced charge transfer (CT) in 4-cyano-4'-(dimethylamino)- and 4-cyano-4'-methoxy-substituted diphenyldimethylsilanes and 2,2-diphenylpropanes was studied. Fluorescence solvatochromism and time-resolved microwave conductivity measurements show that upon photoexcitation a charge separated state (D.+σA.-)* is populated in all compounds. Excited state dipole moments for a given donor-acceptor combination are, irrespective of the bridge, equal. The CT states of the silanes are however lying at lower energies, implying that the presence of silicon thermodynamically facilitates the CT process. Cyclic voltammetry data of model compounds show that this is a consequence of the lowering of the acceptor reduction potential by the silicon bridge. It was however inferred from radiative decay rates that the electronic coupling between the CT and locally excited states as well as the coupling between the ground and CT state is larger for the carbon-bridged compounds. As shown by both solution and solid state electronic spectra and radiative decay rates, the photophysics of the DσA compounds are dominated by intensity borrowing of the CT transitions from transitions localized in the Dσ and σA chromophores.
- Van Walree, Cornelis A.,Roest, Martin R.,Schuddeboom, Wouter,Jenneskens, Leonardus W.,Verhoeven, Jan W.,Warman, John M.,Kooijman, Huub,Spek, Anthony L.
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p. 8395 - 8407
(2007/10/03)
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- Basic azo dyestuffs of the 3-cyano-2,4,6-triamino pyridine series
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The new basic azo dyestuffs of the formula STR1 wherein the symbols have the meaning given in the description, are suitable for dyeing synthetic and naturally occurring substrates which can be dyed with basic dyestuffs.
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- Regioselective nitration of diphenyl compounds
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A regioselective nitration process for diphenyl compounds which can be carried out at about ambient temperature in which each ring of the diphenyl compound is selectively nitrated in the para position to form the corresponding di(4-nitrophenyl) compound. Such compounds as diphenyl carbonate, 2,2-diphenylpropane, 2,2-diphenylhexafluoropropane, diphenyl sulfide, diphenyl ketone, diphenyl sulfone, and the like can be converted to an isomeric mixture containing an enhanced amount of the corresponding di(4-nitrophenyl) compound, which mixture may be reduced or purified and reduced to the di(4-aminophenyl) analogues for use in the manufacture of polyamides, polyimides, and polyamide-imides.
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- Process for preparing diaminodiphenyl-alkanes
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A process is described for the preparation of bis(aminophenyl)alkanes and bis(aminophenyl)cycloalkanes which comprises condensing a m-alkylphenol with an alkanone or cycloalkanone and heating the resulting condensation product with an at least stoichiometric amount of an acid addition salt of aniline or a substituted aniline or a mixture of such amines.
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- Process for the preparation of bis(aminophenyl)alkanes
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An improved process is described for the preparation of bis(aminophenyl)alkanes which comprises heating the corresponding bis(di-alkoxyphenyl)alkane or corresponding cyclic ethers of bis(phenyl)alkanes with an at least stoichiometric proportion of an aniline acid addition salt, optionally in the presence of an inert organic solvent.
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- Chemical process
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Aromatic amines (e.g., aniline) are selectively alkylated in an ortho nuclear position by reaction with an olefin (e.g., ethylene) in the presence of an aluminum anilide catalyst. Hydrogen halides (e.g., HCl) are added to increase the reaction rate.
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