- Preparation and Properties of Pyridine-Analogue of TCNQ Dianion Salt
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Bis(tetrapropyl- and tetrabutylammonium) 1,1'-(2,5-pyridinediyl)bis (4a and 4b) were prepared in order to investigate the properties of pyridine-analogue 3 of TCNQ as a new electron acceptor and its complexation with TTF.Although 3 was not isolated, the cyclic voltammetry of the salt 4 indicated that 3 was a stronger electron acceptor than TCNQ.The charge-transfer complex of TTF and 3 was prepared by mixing TTF with 3 which was generated in situ from electrolytic oxidation of 4 or from the oxidation of 2,5-bis(dicyanomethyl)pyridine, a precursor of 4, with hydrogen peroxide.It consisted of 1:1 composition of donor and acceptor and showed a high electrical conductivity of 19 Scm-1.The 2:1 complex was prepared by metathesis of (TTF)3(BF4)2 and 4, and also highly conductive.
- Hama, Yoshiyuki,Nobuhara, Yukikazu,Aso, Yoshio,Otsubo, Tetsuo,Ogura, Fumio
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- Synthesis and Electronic Properties of Conjugated syn,syn-Dithienothiazine Donor-Acceptor-Donor Dumbbells
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A series of conjugated syn,syn-dithienothiazine donor-acceptor-donor dumbbells is readily synthesized by Suzuki coupling or a one-pot α-lithiation-zincation-Negishi coupling sequence in moderate to good yield. The title compounds are all electron-rich reversible oxidizable redox systems with a relatively narrow range of oxidation potentials according to cyclic voltammetry. UV/Vis and fluorescence spectroscopy however show a significant effect of the electronic nature of the conjugated bridging system on absorption and emission characteristics. Furthermore, a highly polar excited state can be corroborated by Lippert-Mataga analysis of the emission solvatochromicity as well as by TD-DFT calculation of absorption and emission maxima, which classify these dumbbell systems as redox active, luminescent low band gap chromophores with experimentally determined optical band gaps between 2.20 and 2.50 eV.
- Biesen, Lukas,Brüning, Vincent,Janiak, Christoph,Knedel, Tim-Oliver,Müller, Thomas J. J.,Nau, Jennifer
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supporting information
(2022/02/09)
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- Cheap and easy synthesis of highly functionalized (het)aryl iodides via the aromatic finkelstein reaction
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Aryl iodides are superior coupling partners in cross-couplingA- reactions compared to the corresponding chlorides or bromides. Unfortunately, the iodides are much more expensive, if commercially available at all, than the other halides. Thus, it is often mandatory to transform the available bromides into the corresponding iodides. The copper-catalyzed aromatic Finkelstein reaction turned out to be the method of choice to prepare a number of highly functionalized iodo(het)aryls, including pyridines, 2,2′-bipyridines, and chiral compounds. Georg Thieme Verlag Stuttgart? New York.
- Meyer-Eppler, Georg,Kuechler, Lea,Tenten, Christina,Benkhaeuser, Christian,Brueck, Stefanie,Luetzen, Arne
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p. 1085 - 1090
(2014/05/06)
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- Deprotonative metalation of chloro- and bromopyridines using amido-based bimetallic species and regioselectivity-computed CH acidity relationships
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A series of chloro- and bromopyridines have been deprotometalated by using a range of 2,2,6,6-tetramethylpiperidino-based mixed lithium-metal combinations. Whereas lithium-zinc and lithium-cadmium bases afforded different mono- and diiodides after subsequent interception with iodine, complete regioselectivities were observed with the corresponding lithium-copper combination, as demonstrated by subsequent trapping with benzoyl chlorides. The obtained selectivities have been discussed in light of the CH acidities of the substrates, determined both in the gas phase and as a solution in THF by using the DFT B3LYP method.
- Snegaroff, Katia,Nguyen, Tan Tai,Marquise, Nada,Halauko, Yury S.,Harford, Philip J.,Roisnel, Thierry,Matulis, Vadim E.,Ivashkevich, Oleg A.,Chevallier, Floris,Wheatley, Andrew E. H.,Gros, Philippe C.,Mongin, Florence
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experimental part
p. 13284 - 13297
(2012/02/03)
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- Homoleptic zincate-promoted room-temperature halogen-metal exchange of bromopyridines
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Homoleptic lithium tri- and tetraalkyl zincates were reacted with a set of bromopyridines. Efficient and chemoselective bromine-metal exchanges were realized at room temperature with a substoichiometric amount of nBu 4ZnLi2·TMEDA reagent (1/3 equiv; TMEDA=N,N,N′,N′-tetramethylethylenediamine). This reactivity contrasted with that of tBu4ZnLi2·TMEDA, which was inefficient below one equivalent. DFT calculations allowed us to rationalize the formation of N...Li stabilized polypyridyl zincates in the reaction. The one-pot difunctionalization of dibromopyridines was also realized using the reagent stoichiometrically. The direct creation of C-Zn bonds in bromopyridines enabled us to perform efficient Negishi-type cross-couplings. Mild zincation! nBu4ZnLi2·TMEDA (in substoichiometric amounts) promoted efficient and chemoselective room-temperature bromine-metal exchange of a range of bromopyridines (see scheme). DFT calculations strongly supported the formation of a stabilized tripyridylzincate, which could be reacted with electrophiles or be directly involved in palladium-catalyzed cross-coupling reactions.
- Chau, Nguyet Trang Thanh,Meyer, Maxime,Komagawa, Shinsuke,Chevallier, Floris,Fort, Yves,Uchiyama, Masanobu,Mongin, Florence,Gros, Philippe C.
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experimental part
p. 12425 - 12433
(2011/01/05)
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- Synthesis of novel halopyridinylboronic acids and esters. Part 1: 6-Halopyridin-3-yl-boronic acids and esters
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This paper describes a general method for the synthesis and isolation of novel 6-halo-pyridin-3-yl-boronic acids and esters 2-5. These compounds are prepared taking in account a regioselective halogen-metal exchange with a trialkylborate starting from 2,5-dihalopyridines. All substrates studied to date provided a single regioisomeric boronic acid or ester product. Additionally, these compounds have been found to undergo Pd-catalysed coupling with a range of arylhalides and authorise a strategy to produce new pyridines libraries.
- Bouillon, Alexandre,Lancelot, Jean-Charles,Collot, Valérie,Bovy, Philippe R,Rault, Sylvain
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p. 2885 - 2890
(2007/10/03)
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- Studies on Organometallic Compounds. II. Facile and Convenient Method for the Synthesis of Idoazines through Iododestannation of Trimethylstannylazines
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Trimethylsatannyl and bis(trimethylstannyl) derivatives of pyridine, quinoline, and isoquinoline were prepared from the corresponding halo and dihalo (chloro or bromo) derivatives and trimethylstannyl sodium, which was generated in situ from chlorotrimethylsatannane and sodium.These stannyl derivatives readily underwent iododestannation on treatment with iodine to produce the corresponding iodo and diiodo derivatives of pyridine, quinoline, and isoquinoline, respectively, in good yields.Keywords -trimethylsannylazine; bis(trimethylstannyl)azine; iodoazine; diiodoazine; iododestannation; trimethylstannyl sodium; chlorotrimethylstannane
- Yamamoto, Yukata,Yanagi, Akihiko
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p. 1731 - 1737
(2007/10/02)
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