- Examining the role of acceptor molecule structure in self-assembled bilayers: Surface loading, stability, energy transfer, and upconverted emission
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Self-assembly of sensitizer and acceptor molecules has recently emerged as a promising strategy to facilitate and harness photon upconversion via triplet-triplet annihilation (TTA-UC). In addition to the energetic requirements, the structure and relative orientation of these molecules can have a strong influence on TTA-UC rates and efficiency. Here we report the synthesis of five different acceptor molecules composed of an anthracene core functionalized with 9,10- or 2,6-phenyl, methyl, or directly bound phosphonic acid groups and their incorporation into self-assembled bilayers on a ZrO2 surface. All five films facilitate green-to-blue photon upconversion with Φuc as high as 0.0023. The efficiency of TTA, and not triplet energy transfer, fluorescence, or losses via FRET, was primarily responsible for dictating the Φuc emission. Even for molecules having similar photophysical properties, variation in the position of the phosphonic acid resulted in dramatically different ΦTTA, Ith values, γTTA, and D. Interestingly, we observed a strong linear correlation between ΦTTA and the Ith value but the cause of this relationship, if any, is unclear.
- Zhou, Yan,Ayad, Suliman,Ruchlin, Cory,Posey, Victoria,Hill, Sean P.,Wu, Qiang,Hanson, Kenneth
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- Synthesis, crystal structure and photoluminescence of 2,6-dimethylanthracene and its pseudo-triptycene derivatives
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A simple one-step synthesis of 2,6-dimethylanthracene, 1, in high yield is reported utilizing the easily accessible benzyl alcohol as the starting material. Based on 2,6-dimethylanthracene, two pseudo-triptycene compounds, cis-2,6-dimethyl-9,10-dihydroanthracene-9,10-endo-α,β-succinic anhydride, 2, and cis-2,6-dimethyl-9,10-dihydroanthracene-9,10-endo-α,β-succinyl amine, 3, are firstly synthesized in high yield and they are characterized by single crystal X-ray diffraction. Compound 2 crystallizes in triclinic P over(1, ?) space group and compound 3 crystallizes in monoclinic P21/c space group. Both compound 2 and 3 exhibit cis-configurations and endo-conformations. Compound 1 exhibits very intense photoluminescence property due to the delocalized electron in the whole molecule, whereas fluorescence quench happens to some extents due to the destruction of the conjugated structure in compound 2.
- Gong, Yun,Zhou, Yuchao,Qin, Jianbo,Li, Jinghua,Cao, Rong
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- Versatile synthesis of triptycene di- and tetracarboxylic acids
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A simple two-step synthesis of triptycene di- and tetracarboxylic acids is reported. Diels-Alder reaction between dimethylanthracenes and appropriate arynes, generated in situ from anthranilic or dimethylanthranilic acid, afforded di- or tetramethyltriptycenes in 41-69% yields. Subsequent oxidation of the methyl groups with potassium permanganate provided the corresponding triptycene carboxylic acids in 86-96% yields. Georg Thieme Verlag Stuttgart.
- Rybackova, Marketa,Belohradsky, Martin,Holy, Petr,Pohl, Radek,Zavada, Jiri
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- Preliminary investigations on the catalytic hydrogenation of polycyclic aromatic hydrocarbons via WGSR
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The water-gas shift reaction (WGSR) is a crucial reaction in the direct liquefaction of lignite in a syngas (CO + H2) system. In this study, anthracene was utilized as a polycyclic model compound of lignite, to which hydrogen is donated by the H2/D2 produced from CO and H2O/D2O via the WGSR. The results show that the model compound of the polycyclic aromatic hydrocarbon in coal (anthracene) undergoes partial cracking and polycondensation under non-hydrogen-donor conditions at 400 °C. In addition, WGSR catalyzed by NiO can generate hydrogen for the hydrogenation of anthracene. Comparing the mass spectra of deuterated products with those of conventional hydrogenation products by isotope labeling, the alkyl side chain positions of toluene, 1,4-xylene, methylnaphthalene, 1,1-diphenylethylene, methylanthracene and other compounds are prone to deuteration, enabling speculation of the main hydrogenation route of anthracene, which provides theoretical support for the catalytic hydrogenation in direct liquefaction of lignite in a syngas (CO + H2) system.
- Chen, Dabo,Gu, Jiale,Huang, Sheng,Li, Huan,Wu, Shiyong,Wu, Youqing
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- Method for preparing 2,6-dimethyl anthracene from isoprene and 1,4-benzoquinone
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The invention relates to a method for preparing 2, 6-dimethyl anthracene from isoprene and 1, 4-benzoquinone. The process is completed through two steps, firstly, isoprene and 1, 4-benzoquinone are subjected to a two-step Diels-Alder reaction at 80-170 DEG C to generate a dimethyl decahydroanthradione intermediate product, and then the dimethyl decahydroanthradione intermediate product is subjected to dehydrogenation and deoxidation reactions under the action of a metal catalyst to generate 2, 6-dimethyl anthracene. According to the first-step reaction, isoprene and 1, 4-benzoquinone which arederived from biomass resources are used as raw materials, and an intermediate product dimethyl decahydroanthradione is obtained in a tank reactor through common heating or microwave heating; dehydrogenation and deoxidation reactions are carried out in a fixed bed reactor, and a reaction intermediate is directly injected into a reaction tube or passes through a catalyst bed layer under purging ofcarrier gas to obtain 2, 6-dimethyl anthracene. The process is simple in reaction procedure and high in target product selectivity, and a new route for preparing 2,6-dimethyl anthracene from biomass resources is provided.
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Paragraph 0031-0052
(2020/06/17)
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- Design, synthesis and characterization of self-assembled As 2L3 and Sb2L3 cryptands
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The syntheses and X-ray crystal structures of six new self-assembled supramolecular As and Sb-containing cryptands are described. Analysis in the context of previously reported As2L3 and Sb 2L3 cryptands reveals that small differences in ligand geometries result in significant differences in the helicity of the complexes and the stereochemistry of the metal coordination within the assembled complexes. Additionally, a new synthetic route is described which involves exposure of reactants to vacuum to help facilitate self-assembly.
- Fontenot, Sean A.,Cangelosi, Virginia M.,Pitt, Melanie A. W.,Sather, Aaron C.,Zakharov, Lev N.,Berryman, Orion B.,Johnson, Darren W.
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supporting information; experimental part
p. 12125 - 12131
(2012/03/11)
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- Remote aromatic stabilization in radical reactions
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The rates of free radical reduction of a series of anthracene derivatives and 1-phenyl-4-bromodecane with tributyltin hydride are mediated by the remote aromatic substituent in an apparent through-space interaction. Density functional calculations suggest that this enhancement is not due to direct stabilization of the free radical intermediate, and is likely to be achieved through the interaction of the aromatic moiety with the polarized transition state leading to the intermediate.
- Cabellero, Alfonso Garcia,Croft, Anna K.,Nalli, Stefano M.
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p. 3613 - 3615
(2008/09/19)
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- Two-photon absorption properties of 2,6-bis(styryl)anthracene derivatives: Effects of donor-acceptor substituents and the π center
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A series of 2,6- and 2,7-bis-(styryl)anthracene derivatives with the donors at the styryl group and acceptors at the 9,10-positions have been synthesized, and their two-photon cross sections (φδmax) were determined. These compounds exhibit a peak two-photon absorptivity (δmax) in the range of 700-2500 GM at 780-1030 nm. Values of λmax and Stokes shifts increase as the acceptor is changed to a stronger one. There is also a parallel increase in λmax (2) and δmax with the same variation of the chromophore structure. Both λmax(2) and φδmax have been optimized by introducing donor-substituted styryl groups at the 2,6-positions and p-cyanophenyl groups at the 9,10-positions, respectively. The effect of a π center on the two-photon absorption properties has been assessed by comparing the existing data for a variety of D-π-D derivatives.
- Yang, Wen Jun,Kim, Dae Young,Jeong, Mi-Yun,Kim, Hwan Myung,Lee, Yun Kyoung,Fang, Xingzhong,Jeon, Seung-Joon,Cho, Bong Rae
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p. 4191 - 4198
(2007/10/03)
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- 2,6-Bis(styryl)anthracene derivatives with large two-photon cross-sections
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The first synthesis of 2,6-bis(styryl)anthrance derivatives with very large two-photon cross sections is reported.
- Yang, Wen Jun,Kim, Dae Young,Jeong, Mi-Yun,Kim, Hwan Myung,Jeon, Seung-Joon,Cho, Bong Rae
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p. 2618 - 2619
(2007/10/03)
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- Friedel-Crafts Reaction with Arylcarbinols : One-Pot Synthesis of 10-Methylbenzo[a]fluoranthene
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Friedel-Crafts reaction with some monoaryl and diaryl carbinols have been studied. The products suggest a rational mode of formation of trityl alcohol and anthracene derivatives modifying the earlier reported conjecture of their formation from carbon monoxide, generated from benzhydrol and solvent benzene. It now appears that during Friedel-Crafts reaction the benzyl carbocation generated from benzhydrol may be arylated to triphenylmethane derivative. The latter under the experimental condition forms trityl cation which abstracts the hydroxyl group from the benzhydrol to form benzyl carbocation and trityl alcohol. Benzyl carbocations act both as a nucleophile and an eletrophile and dimerize to form anthracene derivatives. Incidentally, a one-pot synthesis of 10-methylbenzo[a]fluoranthene (26), characterized by NOE, decoupling and mass spectral studies, has been achieved in good yield by the Friedel-Crafts reaction of 9-fluourenol, thus providing a simple method of its synthesis.
- Talapatra, Bani,Chakraborty, Syamal,Biswas, Kallolmay,Mondal, Sudipta,Talapatra, Sunil Kumar
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p. 788 - 794
(2007/10/03)
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- Dealkylation of tert-butylcalix[n]arenes in toluene: Formation of 2,6 and 2,7-dimethylanthracenes
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An eutectic mixture of 2.6-dimethylanthracene VI and 2,7-dimethylantracene VII was formed during deterbutylation reaction of calix[n]arenes in toluene with aluminium chloride as catalyst. Using the deterbutylation of p-tert- butylcalix |4]arene I as a model we propose a mechanism of their formation. Springen Verlag Iberica 1997.
- Yao, Benjamin,Bassus, Jacques,Lamartine, Roger
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p. 165 - 167
(2007/10/03)
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- An Efficient Reduction of Anthrones to Anthracenes
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An efficient and general means of reducing anthrones to anthracenes has been developed.The procedure, which uses NaBH4 as the reducing agent in a mixed solvent system of diglyme/methanol, produced anthracenes in essentially quantitative yield from a variety of anthrones.
- Marquardt, Donald J.,McCormick, Frankie A.
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p. 1131 - 1134
(2007/10/02)
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- An E.S.R. Investigation of Radical Cations Formed in Friedel-Crafts Reactions
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The present study deals with the detection and identification of radical cations produced in a Friedel-Crafts alkylating system, with benzene, toluene, or ethylbenzene, and an alkyl chloride.Our results indicate that the observed e.s.r. spectra are due to polycyclic aromatic radical cations formed from the parent hydrocarbons.It is suggested that benzyl halides produced in the Friedel-Crafts alkylating reaction undergo Scholl self-condensation to give polycyclic aromatic hydrocarbons, which are converted into the corresponding polycyclic aromatic radical cations in the presence of aluminium chloride.
- Wang, Hanqing,Kispert, Lowell. D.,Sang, Hong
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p. 1463 - 1470
(2007/10/02)
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- The Question of Friedel-Crafts Transformylations. Acid-Catalyzed Reactions of Aromatic Aldehydes with Arenes
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The reactions of aromatic aldehydes with various arenes in the presence of Lewis and Broensted acids have been examined with the aim of determining if transformylations occur.No evidence for such transformylations was obtained.The major initial reaction is nucleophilic addition of the arene to the carbonyl group of the aldehyde to produce a diarylmethanol, followed by reaction with a second molecule of arene with elimination of water to produce a triarylmethane.Further reactions include (1) reversible dealkylations/realkylations of triarylmethanes to yield di- and triarylmethanes having aromatic nuclei corresponding to those of both the initial aldehyde and the arene and (2) alkylation, cyclialkylation, and dealkylation reactions that result in the formation of anthracene and/or substituted anthracenes and dihydroanthracenes.The anthracene and dihydroanthracene derivatives are produced in significant amounts only when aluminum chloride is the acid catalyst.The mechanisms of the reactions of aromatic aldehydes with arenes in the presence of aluminum chloride are discussed and compared with reactions of aromatic ketones.
- Roberts, Royston M.,El-Khawaga, Ahmed M.,Sweeney, Kevin M.,El-Zohry, Maher F.
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p. 1591 - 1599
(2007/10/02)
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