Molecular paramagnetic semiconductor: crystal structures and magnetic and conducting properties of the Ni(dmit)(2) salts of 6-oxoverdazyl radical cations (dmit = 1,3-dithiol-2-thione-4,5-dithiolate).
Molecular paramagnetic semiconductor: crystal structures and magnetic and conducting properties of the Ni(dmit)(2) salts of 6-oxoverdazyl radical cations (dmit = 1,3-dithiol-2-thione-4,5-dithiolate).
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DOI：
10.1021/ic030068q
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发表时间：
2004-01
影响因子：
4.6
通讯作者：
Kyohei Mukai;N. Senba;T. Hatanaka;H. Minakuchi;K. Ohara;M. Taniguchi;Y. Misaki;Y. Hosokoshi;K. Inoue;N. Azuma
中科院分区：
文献类型：
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作者：
Kyohei Mukai;N. Senba;T. Hatanaka;H. Minakuchi;K. Ohara;M. Taniguchi;Y. Misaki;Y. Hosokoshi;K. Inoue;N. Azuma
四种1：1和1：3-[4-（4-氨基苯基）-2-甲基-3-氧代-4-甲基-2-氧代-3-氧代-4-氧代-3-氧代-4-氧代-4-氧代-3-氧代-4-氧代-4-氧代-@@（三甲基铵基）苯基]-1，5-二苯基-6-氧代咪唑基自由基阳离子（[1]（+））及其单-和二甲基衍生物（[2]（+）和[3]（+））与Ni（dmit）（2）阴离子（dmit = 1，3-二硫醇-2-正-4，5-二硫醇盐）（[1]（+）[Ni（dmit）（2）]（-）（4），[2]（+）[Ni（dmit）（2）]（-）（5），[3]（+）[Ni（dmit）（2）]（-）（6）和[1]（+）[Ni（dmit）（2）]（3）（-）（7）），并在1.8 - 300 K之间测量了它们的磁化率（chi（M））。盐5和盐7的chi（M）值可以通过来自（i）的贡献的总和很好地再现。居里-韦斯系统，居里常数为0.376（Kemu）/mol，负韦斯常数（THETAV）为-0.4和-1.7 K，和（ii）.具有强负交换相互作用的二聚体系统，其2J/k（B）分别为-354和-258 K。Ni（dmit）（2）阴离子中的二聚体形成已通过盐4 - 6的晶体结构分析确定。在盐4和6中，Ni（dmit）（2）二聚体分子夹在两个Verdazyl阳离子之间，表明在4和6中形成线性四聚体。盐4和盐6的磁化率数据已被拟合为线性四聚体模型，其中分别使用4的末端交换相互作用2J（1）/k（B）=-600 K和中心相互作用2J（2）/k（B）=-280 K以及6的2J（1）/k（B）=-30 K和2J（2）/k（B）=-580 K。通过ESR测量获得的盐4 - 6中g（T）值的温度依赖性的结果也支持上述分析。1：1盐4 - 6是绝缘体。另一方面，1：3盐7在20 ℃下的电导率为σ = 0.10S cm（-）（1），活化能E（A）= 0.099eV，显示出半导体性质。盐7是一种新的分子顺磁半导体。
Four kinds of 1:1 and 1:3 salts of 3-[4-(trimethylammonio)phenyl]-1,5-diphenyl-6-oxoverdazyl radical cation ([1](+)) and its mono- and dimethyl derivatives ([2](+) and [3](+)) with Ni(dmit)(2) anions (dmit = 1,3-dithiol-2-thione-4,5-dithiolate) ([1](+)[Ni(dmit)(2)](-) (4), [2](+)[Ni(dmit)(2)](-) (5), [3](+)[Ni(dmit)(2)](-) (6), and [1](+)[Ni(dmit)(2)](3)(-) (7)) have been prepared, and the magnetic susceptibilities (chi(M)) have been measured between 1.8 and 300 K. The chi(M) values of salts 5 and 7 can be well reproduced by the sum of the contributions from (i). a Curie-Weiss system with a Curie constant of 0.376 (K emu)/mol and negative Weiss constants (THETAV;) of -0.4 and -1.7 K and (ii). a dimer system with strong negative exchange interactions of 2J/k(B) = -354 and -258 K, respectively. The dimer formations in Ni(dmit)(2) anions have been ascertained by the crystal structure analyses of salts 4-6. In salts 4 and 6, Ni(dmit)(2) dimer molecules are sandwiched between two verdazyl cations, indicating the formation of a linear tetramer in 4 and 6. The magnetic susceptibility data for salts 4 and 6 have been fitted to a linear tetramer model using an end exchange interaction of 2J(1)/k(B) = -600 K and a central interaction of 2J(2)/k(B) = -280 K for 4 and 2J(1)/k(B) = -30 K and 2J(2)/k(B) = -580 K for 6, respectively. The results of the temperature dependence of the g(T) value in salts 4-6 obtained by ESR measurement also support the above analyses. The 1:1 salts 4-6 are insulators. On the other hand, the conductivity of the 1:3 salt 7 at 20 degrees C was sigma = 0.10 S cm(-)(1) with an activation energy E(A) = 0.099 eV, showing the semiconductor property. Salt 7 is a new molecular paramagnetic semiconductor.