Effect of Included Solvent Molecules on the Physical Properties of the Paramagnetic Charge Transfer Salts beta' '-(bedt-ttf)(4)[(H(3)O)Fe(C(2)O(4))(3)].Solvent (bedt-ttf = Bis(ethylenedithio)tetrathiafulvalene).
Effect of Included Solvent Molecules on the Physical Properties of the Paramagnetic Charge Transfer Salts beta' '-(bedt-ttf)(4)[(H(3)O)Fe(C(2)O(4))(3)].Solvent (bedt-ttf = Bis(ethylenedithio)tetrathiafulvalene).
复制标题
包含的溶剂分子对顺磁性电荷转移盐β-(bedt-ttf)(4)[(H(3)O)Fe(C(2)O(4))(3)]物理性质的影响
DOI：
10.1021/ic990102u
复制
发表时间：
1999
影响因子：
4.6
通讯作者：
S. A. French
中科院分区：
文献类型：
--
作者：
S. Turner;P. Day;K. Malik;M. Hursthouse;S. Teat;E. Maclean;Lee Martin;S. A. French
新的电荷转移盐β′′-(bedt-ttf)(4)[(H(3)O)Fe(C(2)O(4))(3)].C(5)H（5)N， I, （bedt-ttf =双（乙二硫代）四噻吩））晶体结构与已报道的盐β′-(bedt-ttf)(4)[(H(3)O)Fe(C(2)O(4))(3)].C(6)H(5)CN， II非常相似，超导临界温度为8.6 K。然而，变温磁性和输运实验表明，在116 K时，I具有金属到绝缘体的转变。在（150k）以上和（90k）以下金属向绝缘体转变时，确定了I的晶体结构，并与II的结构进行了比较。吡啶溶剂化物在单斜空间群C2/c中结晶，在150 K时a = 10.267(2) Å， b = 19.845(4) Å， c = 34.907(7) Å， β = 93.22(3)度，Z = 4；在90 K时a = 10.2557（15） Å， b = 19.818（28） Å， c = 34.801（49） Å， β = 93.273（14）度，Z = 4。I和II的结构均由每分子带+0.5形式电荷的bedt-ttf层和含有H(3)O（+）和[Fe(C(2)O(4))(3)](3)（-）的近似六方对称层组成。溶剂分子占据由阴离子层形成的六角形空腔。将溶剂分子从C(6)H(5)CN变为C(5)H(5)N，会引起bedt-ttf层的无序，从而导致观察到的物理性质的巨大差异。对于I，在150k时，1 / 2的bedt-ttf分子与II中所有分子的构象相同每个bedt-ttf分子的末端乙烯基团相对于分子的另一端是扭曲和重叠的。剩下的50%的bedt-ttf分子有无序的乙烯基团。这种无序在90k时仍然存在，它可以分解成两种构象：扭曲-扭曲重叠构象和扭曲-扭曲交错构象。
The new charge transfer salt, beta' '-(bedt-ttf)(4)[(H(3)O)Fe(C(2)O(4))(3)].C(5)H(5)N, I, (bedt-ttf = bis(ethylenedithio)tetrathiafulvalene) has a crystal structure closely similar to that of the reported salt beta' '-(bedt-ttf)(4)[(H(3)O)Fe(C(2)O(4))(3)].C(6)H(5)CN, II, which has a superconducting critical temperature of 8.6 K. However, variable temperature magnetic and transport experiments show that I has a metal to insulator transition at 116 K. The crystal structure of I has been determined above (150 K) and below (90 K) the metal to insulator transition and comparisons are made with the structure of II. The pyridine solvate crystallizes in the monoclinic space group C2/c with a = 10.267(2) Å, b = 19.845(4) Å, c = 34.907(7) Å, beta = 93.22(3) degrees, Z = 4 at 150 K and with a = 10.2557(15) Å, b = 19.818(28) Å, c = 34.801(49) Å, beta = 93.273(14) degrees, Z = 4 at 90 K. The structures of I and II both consist of layers of bedt-ttf with +0.5 formal charge per molecule and layers of approximately hexagonal symmetry containing H(3)O(+) and [Fe(C(2)O(4))(3)](3)(-). The solvent molecules occupy hexagonal cavities formed by the anionic layer. Changing the solvent molecule from C(6)H(5)CN to C(5)H(5)N induces disorder in the bedt-ttf layer which accounts for the dramatic difference in observed physical properties. For I, at 150 K, one-half of all the bedt-ttf molecules have identical conformations to all the molecules in II where both terminal ethylene groups of each bedt-ttf molecule are twisted and eclipsed with respect to the opposite end of the molecule. The remaining 50% of bedt-ttf molecules in I have disordered ethylene groups. The disorder persists at 90 K where it can be resolved into two conformations: twisted-twisted eclipsed and twisted-twisted staggered.