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Syntheses, Structure and Conducting Properties of Halogenated Ethylenedioxytetrathiafulvalenes

2001; Elsevier BV; Volume: 54; Issue: 2 Linguagem: Inglês

10.3987/com-00-s(i)79

1881-0942

Masahiko Iyoda, Yoshiyuki Kuwatani, E. Ogura, Kenji Hara, Hironori Suzuki, Takahiro Takano, Koji Takeda, Junichi Takano, Kohei Ugawa, Masato Yoshida, Haruo Matsuyama, Hiroyuki Nishikawa, Isao Ikemoto, Takehiro Kato, N. Yoneyama, Junichi Nishijo, Akira Miyazaki, Toshiaki Enoki,

Magnetism in coordination complexes

Abs tract-4,5-Diiodo-, 4,5-dibromo-, and 4,5-dichloro-4' ,5' -ethylenedioxytetrathiafulvalenes (EDO-TTFI 2 , EDO-TTFBr 2 , and EDO-TTFCl 2 ) were synthesized in moderate to good yields by the two routes.The first route contains the reaction of EDO-TTF with LDA, followed by quenching with halogenated reagents, and the second route consists of the P(OR) 3 -mediated cross-coupling of 4,5-dihalogenated 1,3-dithiole-2-ones with 4,5-ethylenedioxy-1,3-dithiole-2-thione.The structures of EDO-TTFI 2 and EDO-TTFCl 2 were determined by X-Ray analysis.The radical-cation salts derived from EDO-TTFI 2 , EDO-TTFBr 2 , and EDO-TTFCl 2 show high conductivities, although these compounds contain electron-withdrawing halogens as the substituent.can be enhanced by electrostatic interaction to increase dimensionality of the molecular conductors . 4,5 ng them, the substitution of halogen atoms on the TTF framew ork has been extensively studied, 6,7 although the electronegativity of halogens decreases the donor properties, thus causing difficulty in forming molecular conductors.Previously, we reported the synthesis and unique conductivities of CT-complexes and radical salts of halogenated ethylenedithiotetrathiafulvalenes (EDT-TTFX 2 ' s) and dis clos ed an interes ting behavior of halogen-s ubstituents in the crys tals. 8Our continuing interests in the w eak interaction between halogens and chalcogens in crys tals prompted us to inves tigate the halogenated derivatives of EDO-TTF (1 ).We report here the synthesis of EDO-TTFI 2 (2), EDO-TTFBr 2 (3), and EDO-TTFCl 2 (4) and the properties of their CT-complexes and radical s alts, together with the X-Ray structures of 2-4 and their radical-cation salts.