- A dual–ion battery using diamino–rubicene as anion–inserting positive electrode material
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A novel and non-polymeric anion-inserting electrode material has been designed and prepared for promoting research on molecular ion rechargeable batteries: 5,12-diaminorubicene (DARb). The apolar core structure of a rubicene molecule has been coupled to two amino-groups for producing an original conjugated primary diamine exhibiting low affinity for polar solvents such as common carbonate-based battery electrolytes. The electrochemical reactivity of this organic molecule has been probed in a dual-ion cell configuration (vs. Li) using six different electrolyte formulations in terms of solvent (PC, EC-DMC) and lithium salt (LiPF6, LiClO4, LiTFSI). This diamino-rubicene material systematically showed a reversible electroactivity and promising performances when using 1?M LiPF6 in EC:DMC (1:1?vol.%) as the electrolyte, such as an average potential of ~?3.4?V vs. Li+/Li0, an initial capacity of 115?mAh·g??1 and a good capacity retention over 60?cycles without any optimization.
- Deunf, élise,Jiménez, Pablo,Guyomard, Dominique,Dolhem, Franck,Poizot, Philippe
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- Facile Synthesis of Rubicenes by Scholl Reaction
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The treatment of 9,10-diphenylanthracenes with DDQ in the presence of TfOH readily gave the corresponding rubicene derivatives in good yields. The effects of oxidant, acid, substituent, and other conditions are discussed. This protocol involving the Schol
- Kawamura, Masahiko,Tsurumaki, Eiji,Toyota, Shinji
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- Probing mechanisms of aryl-aryl bond cleavages under flash vacuum pyrolysis conditions
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Several biaryls have been subjected to flash vacuum pyrolysis (FVP) at 1100°C and 0.8-0.9hPa. Product compositions are reported for the FVP of 9-phenylanthracene (1), 2-bromobiphenyl (5), biphenyl (8), 1,10- diphenylanthracene (12), 9-(2-naphthyl)anthracene (17), and 9,9′- bianthracenyl (20). The experimental results have been used to evaluate four possible mechanistic pathways for the cleavage of aryl-aryl bonds under these conditions: (1) the 'explosion' of substituted phenyl radicals; (2) hydrogen atom attachment to an ipso-carbon atom of the biaryl followed by C-C bond cleavage; (3) direct homolysis; and (4) loss of a fragment as an aryne. None of these mechanisms by itself successfully accommodates all of the experimental facts. The data suggest that aryl-aryl bond cleavages under FVP conditions involve at least two different mechanistic pathways and that the relative contributions of the competing pathways probably vary from one biaryl to the next.
- Jackson, Edward A.,Xue, Xiang,Cho, Hee Yeon,Scott, Lawrence T.
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p. 1279 - 1287
(2014/11/08)
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- Microwave flash pyrolysis: C9h8 interconversions and dimerisations
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The pyrolysis of 2-ethynyltoluene, indene, fluorene, and related compounds has been studied by sealed tube microwave flash pyrolysis (MFP), in concert with modelling of putative mechanistic pathways by density functional theory (DFT) computations. In the MFP technique, samples are admixed with graphite and subjected to intense microwave power (150-300 W) in a quartz reaction tube under a nitrogen atmosphere. The MFP reaction of 2-ethynyltoluene gave mostly indene, the product of a Roger Brown rearrangement (1,2-H shift to a vinylidene) followed by insertion. An additional product was chrysene, the likely result of hydrogen atom loss from indene followed by dimerisation. The intermediacy of dimeric bi-indene structures was supported by pyrolysis of bi-indene and by computational models. Benzo[a]anthracene and benzo[c]phenanthrene are minor products in these reactions. These are shown to arise from pyrolysis of chrysene under the same MFP conditions. MFP reaction of fluorene gave primarily bi-fluorene, bifluorenylidene, and dibenzochrysene, the latter derived from a known Stone-Wales rearrangement.
- Ajaz, Aida,Voukides, Alicia C.,Cahill, Katharine J.,Thamatam, Rajesh,Skraba-Joiner, Sarah L.,Johnson, Richard P.
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p. 1301 - 1308
(2014/11/07)
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- Proton-catalyzed, silane-fueled friedel-crafts coupling of fluoroarenes
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The venerable Friedel-Crafts reaction appends alkyl or acyl groups to aromatic rings through alkyl or acyl cation equivalents typically generated by Lewis acids. We show that phenyl cation. Friedel-Crafts reaction to intramolecular aryl couplings. The enabling feature of this reaction is the exchange of carbon-fluorine for silicon-fluorine bond enthalpies; the reaction is activated by an intermediate silyl cation. Catalytic quantities of protons or silyl cations paired with weakly coordinating carborane counterions initiate the reactions, after which proton transfer in the final aromatization step regenerates the active silyl cation species by protodesilylation of a quaternary silane. The methodology allows the high-yield formation of a range of tailored polycyclic aromatic hydrocarbons and graphene fragments.
- Allemann, Oliver,Duttwyler, Simon,Romanato, Paola,Baldridge, Kim K.,Siegel, Jay S.
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experimental part
p. 574 - 577
(2011/11/29)
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- A new Suzuki-Heck-type coupling cascade: Indeno[1,2,3]-annelation of polycyclic aromatic hydrocarbons
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Under palladium catalysis, o-bromobenzeneboronic acid can be coupled with 1-bromonaphthalene (6) and with oligocyclic bromoarenes to furnish indeno-annelated polycyclic aromatic hydrocarbons 1-4 and 25 in a single operation in moderate to good yields (27-87%). Alternatively, o-dibromoarenes and 1,2-dibromocycloalkenes can be cross-coupled with 1-naphthaleneboronic acid under the same conditions to yield analogous products (6-87%), and indenocorannulene (19) can be prepared likewise in a single step from pinacol corannuleneboronate (18) (40%).
- Wegner, Hermann A.,Scott, Lawrence T.,De Meijere, Armin
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p. 883 - 887
(2007/10/03)
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- Synthesis of Highly Pure Rubicene and Rubicene Derivatives
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A simple one-step synthesis of highly pure rubicene (2) from fluorenone (1) and magnesium with 24percent yield is described and compared with other preparation procedures.Mono- and di-substituted rubicene derivatives are prepared by electrophilic aromatic substitution.
- Sachweh, Volker,Langhals, Heinz
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p. 1981 - 1987
(2007/10/02)
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- C = C Double Bonds with Extreme Reactivity, III. Reactions of 9-(9-Fluorenylidene)xanthene
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According to equations (1) to (4), 9-(9-fluorenylidene)xanthene (2) reacts with sulfur, malonodinitrile, aniline, or thiophenol to give the compounds 3, 5, 7-11, and diphenyl disulfide.
- Schoenberg, Alexander,Singer, Erich,Stephan, Werner
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p. 3762 - 3765
(2007/10/02)
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- STUDIES ON ORGANOPHOSPHORUS COMPOUNDS-XL. REACTIONS OF KETONES WITH 2,4-BIS(4-METHOXYPHENYL)-1,3,2,4-DITHIADIPHOSPHETANE 2,4-DISULFIDE
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Cyclohexanone and cyclopentanone react with (2,4-bis-4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (Lawesson Reagent (LR)) at 80 deg C with formation of new spiro-1,3,5,2-trithiaphosphorines 1 and 2, respectively. 2-Methyl and 2-phenylcyclohexanone also react with LR at 80 deg C producing the enethiols 3 and 4, which on storage are transformed into the sulfides 5 and 6.Unsaturated cyclohexanones 7-9 are transformed into the corresponding thioketones 10-12 after reactions with LR at 60 deg C for a few hours. 2-Hydroxyketones react with LR with formation of 1,3,2-oxathiaphospholes and similarly a 2-aminoketone gave a 1,3,2-thiazaphosphole.Aromatic ketones, reacted with LR to give corresponding thioketones.Thiofluorenone dimerized to form the cyclic disulfide 31, as proved by X-ray analyses.
- Scheibye, S.,Shabana, R.,Lawesson, S.-O.,Romming, C.
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p. 993 - 1002
(2007/10/02)
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