197-61-5Relevant articles and documents
A dual–ion battery using diamino–rubicene as anion–inserting positive electrode material
Deunf, élise,Jiménez, Pablo,Guyomard, Dominique,Dolhem, Franck,Poizot, Philippe
, p. 64 - 68 (2016)
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.
Probing mechanisms of aryl-aryl bond cleavages under flash vacuum pyrolysis conditions
Jackson, Edward A.,Xue, Xiang,Cho, Hee Yeon,Scott, Lawrence T.
, p. 1279 - 1287 (2014/11/08)
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.
Proton-catalyzed, silane-fueled friedel-crafts coupling of fluoroarenes
Allemann, Oliver,Duttwyler, Simon,Romanato, Paola,Baldridge, Kim K.,Siegel, Jay S.
experimental part, p. 574 - 577 (2011/11/29)
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.