Tetraalkyl- and dialkyl-substituted BEDT-TTF derivatives and their cation-radical salts: synthesis, structure, and properties
Tetraalkyl- and dialkyl-substituted BEDT-TTF derivatives and their cation-radical salts: synthesis, structure, and properties
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四烷基和二烷基取代的 BEDT-TTF 衍生物及其阳离子自由基盐：合成、结构和性能
DOI：
10.1039/a809132c
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发表时间：
1999
影响因子：
--
通讯作者：
Jack M. Williams
中科院分区：
文献类型：
--
作者：
A. Kini;J. P. Parakka;U. Geiser;Hsien‐Hau Wang;Felix M. Rivas;E. DiNino;Seddon Y. Thomas;J. D. Dudek;Jack M. Williams
通过Diels-Alder方法合成了有机电子供体分子双(乙二硫基)四硫富瓦烯、BEDT-TTF或Et的四烷基和二烷基衍生物，其中烷基=乙基和丙基。合成了几种新型给体的阳离子自由基盐，并对其结构进行了表征，发现它们所含的给体分子的氧化态(+1、+1.5和+2)高于BEDT-TTF盐类中典型的氧化态+0.5。这一发现的主要原因是四烷基和二烷基衍生物在晶体生长所用的溶剂中具有较高的溶解度。令人惊讶的是，X射线结晶学研究表明，中性四乙基-Et分子中的烷基以及阳离子自由基盐中氧化的四乙基-Et和二乙基-Et分子采用轴向构型，而不是预期的赤道构型。阳离子自由基盐的电学性质被发现要么是绝缘的，要么是半导体的，这与盐中施主分子的较高氧化状态和晶体结构一致。
Tetraalkyl and dialkyl derivatives, where alkyl=ethyl and propyl, of the organic electron donor molecule bis(ethylenedithio)tetrathiafulvalene, BEDT-TTF or ET, have been synthesized via the Diels-Alder approach. Several cation-radical salts of these new donors have been prepared and structurally characterized, and found to contain donor molecules in nominally higher oxidation states (+1, +1.5 and +2) than the typically observed oxidation state of +0.5 in BEDT-TTF salts. The higher solubility of the tetraalkyl and dialkyl derivatives in solvents used for crystal growth is proposed as the principal reason for this finding. Surprisingly, X-ray crystallographic studies reveal that the alkyl groups in the neutral tetraethyl-ET as well as the oxidized tetraethyl-ET and diethyl-ET molecules in their cation-radical salts adopt axial configurations, rather than the expected equatorial configurations. Electrical properties of the cation-radical salts have been found to be either insulating or semiconducting, consistent with the higher oxidation states of the donor molecules in the salts and the crystal structures.