- Ethynylazulenes - Building blocks for novel oligoazulenes with ethynyl and butadiynyl bridges
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The azulenes 3a,b, 6a,b, 9, 12 and 15 ethynylated in the five-membered ring were prepared by Pd-catalysed cross-coupling of the corresponding iodoazulenes 1a,b, 4a,b, 7, 10 and 13, respectively, with trimethylsilylacetylene and subsequent desilylation. The synthesis of some acyclic oligomers 23-30, 32-36 and 38-40 from these ethynylazulenes could be accomplished by oxidative Eglinton coupling as well as Pd/Cu-catalysed cross-coupling reactions with the appropriate iodoazulenes 1a,b, 4b, 31 and 34. The UV/Vis spectra of the novel oligomers 32, 35 and 36 allow an estimation of the bandgap (Eg) of poly(1,3-azulenylethynylene)s lower than 2eV. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Fabian, Kai H. H.,Elwahy, Ahmed H. M.,Hafner, Klaus
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- Syntheses of mono-, di- and triethynylazulenes
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Simple and productive routes to mono-, di- and triethynylazulenes are described. Azulenes ethynylated in the five-membered ring can be prepared on a multigram scale by Pd-catalyzed cross-coupling of iodo- or bromoazulenes with trimethylsilyl-acetylene and subsequent desilylation. 5,7- Diethynylazulene was synthesized by dibromomethylenation of the corresponding dialdehyde and subsequent dehydrobromination. (C) 2000 Elsevier Science Ltd.
- Fabian, Kai H.H.,Elwahy, Ahmed H.M.,Hafner, Klaus
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- Azulene Bridged π-Distorted Chromophores: The Influence of Structural Symmetry on Optoelectrochemical and Photovoltaic Parameters
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Conjugated chromophores possessing π-twisted functionality such as tetracyanobutadiene (TCBD) have emerged as promising active layer materials for organic photovoltaics (OPVs). In this study, we disclose the synthesis of two azulenyl chromophores containing one and two TCBD groups. The symmetrical and unsymmetrical structural characteristics of these molecules inflict dissimilar optoelectronic and electrochemical properties. Based on molar absorptivity, aggregation behavior, HOMO-LUMO energies and other quantum chemical parameters, the symmetrical molecule (TATC2) appears to be a better non-fullerene acceptor (NFA) compared to its unsymmetrical counterpart (TATC1). For instance, higher absorptivity and deeper HOMO-LUMO levels for TATC2 (23950 M?1 cm?1; ?6.01 eV/?3.86 eV) over TATC1 (12200 M1 cm?1; ?5.46 eV/?3.64 eV) was observed. Validating this structure-property relationship on solar cell prototypes exhibited higher photovoltaic parameters (VOC=0.54 V, FF=0.48, JSC=6.42 mA/cm2) for TATC2 than TATC1 (VOC=0.47 V, FF=0.38, JSC=5.77 mA/cm2). Though the device parameters are not high, this work uncovers the intrinsic properties of azulene-tethered twisted chromophores as potential π-semiconductor choice for NFA solar cells. In particular, this report explores the utility of azulene-based π-twisted semiconductors as acceptor material for OPVs with cell efficiencies of 1.70 and 1.04 % for TATC2 and TATC1 respectively.
- Murugan, Palanichamy,Praveen, Chandrasekar,Raheem, Abbasriyaludeen Abdul,Shanmugam, Ramasamy
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p. 1451 - 1460
(2021/11/03)
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- Impact of 2,6-connectivity in azulene: Optical properties and stimuli responsive behavior
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The possible incorporation of the redox active, small donor acceptor molecule azulene as a core structure for potential optoelectronic applications has been evaluated. The synthesis and characterization of different isomers of di(phenylethynyl)azulene 1-4 have been successfully carried out. The photophysical properties as well as their stimuli responsive behavior reflecting their corresponding electronic properties were also investigated. The experimental observations show that 2,6-connection (3) exhibits intense luminescence and shows the strongest stimuli responsive behavior upon acid treatment. DFT calculations of 3 reveal the highest contributions of the alkyne substituents at the 2- and 6-position of the azulene to the ground- and excited state that makes the 2,6-connectivity at azulene a very promising candidate for low band-gap conjugated materials.
- Koch, Michael,Blacque, Olivier,Venkatesan, Koushik
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p. 7400 - 7408
(2013/11/06)
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- An efficient and regioselective iodination of electron-rich aromatic compounds using N-chlorosuccinimide and sodium iodide
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An efficient and regioselective method for iodination of electron-rich aromatic compounds was found using N-chlorosuccinimide and sodium iodide in AcOH with short reaction times. This method is also applicable to non-benzenoid aromatic or heteroaromatic c
- Yamamoto, Takuya,Toyota, Kozo,Morita, Noboru
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experimental part
p. 1364 - 1366
(2010/05/03)
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- Synthesis and Reactivities of 1,5- and 1,7-Azulenequinone Derivatives. A Highly Convenient, One-Pot Synthesis of 3-Bromo-1,5- and -1,7-Azulenequinones by Bromination of Azulene 1,2
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A very convenient, one-pot synthesis (over 80% yield) of 3-bromo-1,5- and -1,7-azulenequinones has been developed by bromination of azulene in aqueous tetrahydrofuran. Reduction of 3-bromo-1,5- and -1,7-azulenequinones with tin or zinc powder in acetic acid gave the parent 1,5- and 1,7-azulenequinones, and further reduction products.
- Wakabayashi, Hidetsugu,Kurihara, Teruo,Shindo, Kimio,Tsukada, Masaaki,Yang, Paw-Wang,Yasunami, Masafumi,Nozoe, Tetsuo
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p. 391 - 400
(2007/10/03)
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- THE IODINATION OF AROMATIC SUBSTRATES ON ALUMINA
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The iodination of a wide variety of aromatic substrates has been attained on dehydrated alumina.The procedure is particularly well suited for arenes.
- Boothe, Richard,Dial, Christopher,Conaway, Richard,Pagni, Richard M.,Kabalka, George W.
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p. 2207 - 2210
(2007/10/02)
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- OXIDATIVE SUBSTITUTION XIV. SUBSTITUTION OF HALOGEN IN AROMATIC RING. NEW THEORIES ABOUT THE MECHANISM OF THE ACTION OF CuX2
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The stoichiometry, the comparative reactivity of halogens and hydrogen, the effect of substituents, and the action of an additional oxidizing agent were determined for the reactions of halogenoazulenes with CuX2., leading to substitution of the halogen by the group X (X = Cl, Br, SCN, SeCN, NO2, SO2, Ph).According to model experiments, the equilibrium CuX2 + CuX+ X+ + 2CuX is possible.The reaction of Cu(SO2Ph)2 with Cu(BF4)2 leads to the formation of two equivalents of a copper(I) salt; short-lived particles which substitute the hydrogen and halogen in the substrate are generated during the reaction.It is suggested that the electron generated during oxidation or autooxidation of CuX2 is capable of combining with the substrate.New methods were found for the synthesis of azulene derivatives, and known methods were improved.
- Nefedov, V.A.,Tarygina, L.K.,Kryuchkova, L.V.,Ryabokobylko, Yu.S.
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p. 487 - 499
(2007/10/02)
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