Novel Selenocycle-Fused TTF-Type of Electron Donors Forming Conducting Molecular Complexes: Bis(ethyleneseleno)tetrathiafulvalene (BES-TTF), Diselenolotetrathiafulvalene (DS-TTF), and Bis(ethyleneseleno)tetraselenafulvalene (BES-TSF)
摘要:
The title selenocycle-fused tetrathiafulvalene derivatives (BES-TTF and DS-TTF) and tetraselenafulvalene derivative (BES-TSF) have been synthesized as novel electron donors, and their conducting molecular complexes have been studied. Although DS-TTF formed only semiconducting complexes, BES-TTF and BES-TSF gave metallic complexes with various electron accepters, such as TCNQ, ClO4-, PF6-, and AsF6-. Among them, the TCNQ complex of BES-TSF showed an extraordinarily high room-temperature conductivity of 2700 +/- 500 S cm(-1), which is of the highest class for a molecular complex. The complexes of BES-TTF underwent a typical metal-to-insulator transition at low temperature, characteristic of one-dimensional organic metals. On the other hand, complexes of BES-TSF were less temperature-dependent and remained highly conducting, even down to cryogenic temperature. The different behaviors of the three donors are discussed on the basis of the crystal structures of their representative complexes as elucidated by X-ray crystallographic analyses.
Novel Selenocycle-Fused TTF-Type of Electron Donors Forming Conducting Molecular Complexes: Bis(ethyleneseleno)tetrathiafulvalene (BES-TTF), Diselenolotetrathiafulvalene (DS-TTF), and Bis(ethyleneseleno)tetraselenafulvalene (BES-TSF)
摘要:
The title selenocycle-fused tetrathiafulvalene derivatives (BES-TTF and DS-TTF) and tetraselenafulvalene derivative (BES-TSF) have been synthesized as novel electron donors, and their conducting molecular complexes have been studied. Although DS-TTF formed only semiconducting complexes, BES-TTF and BES-TSF gave metallic complexes with various electron accepters, such as TCNQ, ClO4-, PF6-, and AsF6-. Among them, the TCNQ complex of BES-TSF showed an extraordinarily high room-temperature conductivity of 2700 +/- 500 S cm(-1), which is of the highest class for a molecular complex. The complexes of BES-TTF underwent a typical metal-to-insulator transition at low temperature, characteristic of one-dimensional organic metals. On the other hand, complexes of BES-TSF were less temperature-dependent and remained highly conducting, even down to cryogenic temperature. The different behaviors of the three donors are discussed on the basis of the crystal structures of their representative complexes as elucidated by X-ray crystallographic analyses.
An efficient synthesis of one new (10) and three previously reported (9, 11, and 12) pi-electron donors, which have one sulfur atom in each of the outer five-membered rings attached to the TTF system, is presented. The radical cations derived from 9-11 have been studied by ESR spectroscopy and the spin density distribution of these radical cations, as well as those of other related radical cations, have been determined by MO calculations and correlated with the ESR spectral data. The single-crystal X-ray structures of pi-donors 9 and 12 are reported. The most remarkable fact of these structures is the transverse intermolecular contacts between interstacked molecules. The external sulfur atoms of 9 play a central role in its transverse structural pattern. Complexes of donors 9 and 10 with tetracyano-p-quinodimethane (TCNQ) and tetrafluorotetracyano-p-quinodimethane (TC-NQF(4)) have been obtained and characterized.
Rovira Concepcio, Veciana Jaume, Santalo Nuria, Tarres Judit, Cirujeda Jo+, J. Org. Chem, 59 (1994) N 12, S 3307- 3313