- Organization of acenes with a cruciform assembly motif
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This study explores the assembly in the crystalline state of a class of pentacenes that are substituted along their long edges with aromatic rings forming rigid, cruciform molecules. The crystals were grown from the gas phase, and their structures were co
- Miao, Qian,Chi, Xiaoliu,Xiao, Shengxiong,Zeis, Roswitha,Lefenfeld, Michael,Siegrist, Theo,Steigerwald, Michael L.,Nuckolls, Colin
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- Luminescent properties of pentacene derivatives with naphthalene moiety
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Pentacene moiety in electro-optical device which includes solar cell and organic light-emitting diodes (OLEDs) has attracted lots of interest because of its high carrier mobility and dopant property. We synthesized new conjugated compounds, 6,13-diphenylp
- Kim, Yeong-Eun,Park, Jong-Wook
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- Exciton Isolation in Cross-Pentacene Architecture
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Null aggregates are an elusive, emergent class of molecular assembly categorized as spectroscopically uncoupled molecules. Orthogonally stacked chromophoric arrays are considered as a highlighted architecture for null aggregates. Herein, we unveil the nul
- Lijina,Benny, Alfy,Ramakrishnan, Remya,Nair, Nanditha G.,Hariharan, Mahesh
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- Application of zirconacyclopentadienes (metalla-heterocycles) and cross-coupling for the convenient preparative method of 6,13-disubstituted pentacene
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Iodination of zirconacyclopentadiene derivative gave diiododiene derivative. The product was lithiated with t-BuLi and treated with diiodonaphthalene successively to afford 6,13-bis(trimethylsilyl)-5,14- dihydropentacene. A 6,13-diiodo-5,14-dihydropentacene was synthesized by iodination of 6,13-bis(trimethylsilyl)-5,14-dihydropentacene with ICl. This diiododihydropentacene was used for the introduction of substituent at 6 and 13 positions by the cross-coupling reactions with Pd catalyst. After aromatization by a combination of DDQ and γ-terpinene or triethylamine, 6,13-disubstituted pentacene derivatives were synthesized.
- Jia, Zhiying,Li, Shi,Nakajima, Kiyohiko,Kanno, Ken-Ichiro,Song, Zhiyi,Takahashi, Tamotsu
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p. 1495 - 1506
(2013/08/23)
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- Substituent effects in pentacenes: Gaining control over HOMO-LUMO gaps and photooxidative resistances
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A combined experimental and computational study of a series of substituted pentacenes including halogenated, phenylated, silylethynylated and thiolated derivatives is presented. Experimental studies include the synthesis and characterization of six new and six known pentacene derivatives and a kinetic study of each derivative under identical photooxidative conditions. Structures, HOMO-LUMO energies and associated gaps were calculated at the B3LYP/6-311+G**//PM3 level while optical and electrochemical HOMO-LUMO gaps were measured experimentally. The combined results provide for the first time a quantitative assessment of HOMO-LUMO gaps and photooxidative resistances for a large series of pentacene derivatives as a function of substituents. The persistence of each pentacene derivative is impacted by a combination of steric resistance and electronic effects as well as the positional location of each substituent. Silylethynyl-substituted pentacenes like TIPS-pentacene possess small HOMO-LUMO gaps but are not the longest lived species under photooxidative conditions, contrary to popular perception. A pentacene derivative with both chlorine substituents in the 2,3,9,10 positions and o-alkylphenyl substituents in the 6,13 positions is longer lived than TIPS-pentacene. Of all the derivatives studied, alkylthio- and arylthio-substituted pentacenes are most resistant to photooxidation, possess relatively small HOMO-LUMO gaps and are highly soluble in a variety of organic solvents. These results have broad implications for the field of organic molecular electronics where OFET, OLED, and other applications can benefit from highly persistent, solution processable pentacene derivatives.
- Kaur, Irvinder,Jia, Wenling,Kopreski, Ryan P.,Selvarasah, Selvapraba,Dokmeci, Mehmet R.,Pramanik, Chandrani,McGruer, Nicol E.,Miller, Glen P.
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supporting information; experimental part
p. 16274 - 16286
(2009/05/08)
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- Photooxidation and reproduction of pentacene derivatives substituted by aromatic groups
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Pentacene derivatives substituted by aromatic groups at the 6,13-positions were prepared and investigated for their electronic properties and the photoaddition reaction with oxygen. The pentacene derivatives substituted by 2-thienyl and phenyl groups reac
- Ono, Katsuhiko,Totani, Hiroaki,Hiei, Takao,Yoshino, Akihiro,Saito, Katsuhiro,Eguchi, Katsuya,Tomura, Masaaki,Nishida, Jun-ichi,Yamashita, Yoshiro
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p. 9699 - 9704
(2008/02/12)
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- CYCLOADDITIONS OF 1,3,4-OXADIAZIN-6-ONES
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From substituted 2-oxoethanoic acids and acylhydrazines the corresponding hydrazones 1 are prepared, which can be cyclized to give the title compounds 2.The reactions of 2 with activated alkynes (yneamines, cyclooctyne, dehydrobenzene) proceed as -cycloadditions and result in the formation of α-pyrones after loss of nitrogen.Reactions of this type are possible also intramolecularly, if the oxadiazinones (2r-u) contain a properly located alkyne group.Oxadiazinones 2 undergo Diels-Alder cycloadditions with a variety of olefins.Diaryloxadiazinones react with alkenes which are activated by ring strain (cyclopropene, cyclobutene, trans-cyclooctene), by a high-lying HOMO (benzvalene, styrene, enamines), or by the factor > in the case of norbornene.The methyl phenyloxadiazinonecarboxylate 2p is highly reactive and takes up even 1-octene and cyclohexene.The primary adducts of type 54 readily extrude nitrogen to give 4,5-dihydropyrylium-2-olates (60) as most probable but not observed intermediates.In one case the expected -cycloadduct, namely 26, could be isolated.The ultimate products are generally derived either from 60 or from γ-keto ketenes 53, which are believed to be in equilibrium with 60. γ-Keto ketenes 53 have been detected with many systems and are stable in certain cases.When diphenyloxadiazinone, 2a, was treated with norbornene, norbornadiene, cyclopentene, trans-cyclooctene, or styrene, enol lactones of type 63 were isolated, which are considered to be formed from the intermediate dihydropyryliumolates 62 by a suprafacial -H shift.Cyclopropenes and cyclobutene transform oxadiazinones 2 to α,β-unsaturated seven-membered enol lactones 64-67 and eight-membered enol lactone 69, respectively.These products are believed to be the result of valence isomerizations of the corresponding dihydropyryliumolates (74, 75).Enamines behave exceptionally in that they can convert the oxadiazinones 2 into products not derived from the -cycloaddition (e.g. 82, 88, 89), although the latter process is dominating in most examples investigated to date.The compounds obtained from the usual -cycloadditions are amides of α,β-unsaturated δ-oxo acids (78, 80) and α,β-unsaturated δ-amino-δ-lactones (81).The former are believed to arise from α-amino-γ-keto ketene intermediates (76) by -amino migrations, whereas the formation of the latter (81) can be rationalized in two different ways, one being a -amino migration starting from the possible intermediates 85 (4-amino-4,5-dihydropyrylium-2-oltes).Cyclobutanone derivatives 50 and 52 and cyclopentanone derivatives 16 originate from γ-keto ketenes generated from cis,trans-1,5-cyclooctadiene, o-vinylstyrene, and benzvalene, respectively.In these cases, intramolecular cycloaddition of the ketene functionality occurs across either the CC double bond or the strained bicyclo-butane sigma bond, respectively.Intermolecular -cycloadditions of the corresponding γ-keto ketenes with cyclopentadiene, 2,3-dihydrofuran, and ...
- Christl, Manfred
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- TRANSFORMATIONS THERMIQUES DES PHOTOOXYDES MESO DES ACENES-VI. CAS DES PHOTOOXYDES DE PENTACENES
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Thermolysis of the meso-pentacenic photooxides 1P, 1dP and 1tP, in solution, brings about various isomerizations which appear strongly affected by the phenyl substituents.Thus the pentacene photooxide 1P gives only the bicyclic acetal 9P, beside pentacenequinone 5P in high ratio.With the photooxides 1dP of 6,13-diphenylpentacene and 1tP of 5,7,12,14-tetraphenylpentacene, the main products are the naphthocyclobutenic diethers 8dP and 8tP, which are formed in competition with the bicyclic acetals 9dP and 9tP and, in the first case, with an isomer of a new kind, the bis-naphthofuranic diether 13dP.These discrepancies are interpreted in terms of the effect of phenyl groups on the successive steps of the previously established isomerization process of meso-acenic photooxides. Comparative analysis of the chemical shifts of the central carbon atoms, in (13)C NMR, allows the unambiguous assignment of the structure of each isomer.
- Sparfel, D.,Gobert, F.,Rigaudy, J.
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p. 2225 - 2235
(2007/10/02)
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