Large static first and second hyperpolarizabilities dominated by excess electron transition for radical ion pair salts M2•+ TCNQ•- (M = Li, Na, K)
Large static first and second hyperpolarizabilities dominated by excess electron transition for radical ion pair salts M2•+ TCNQ•- (M = Li, Na, K)
复制标题
DOI：
10.1039/b809161g
复制
发表时间：
2009-01-01
影响因子：
3.3
通讯作者：
Aoki, Yuriko
中科院分区：
文献类型：
--
作者：
Li, Zong-Jun;Wang, Fang-Fang;Aoki, Yuriko
自由基离子对盐M-2（中心点+）TCNQ（中心点-）（M = Li，Na，K）是一类特殊的过剩电子电荷转移配合物，其基态为三重态。在密度泛函理论（DFT）B3 LYP/6-31+ G（d）水平上计算了M-2（centerdot+）TCNQ（centerdot-）（M = Li，Na，K）的全实频率C-2 v对称性几何结构.本文所有的电学性质计算都是在限制性开壳层二阶Moller-Plesset微扰理论（ROMP 2）水平上进行的。由于存在过量电子（来自极化碱金属原子），这些电荷转移配合物表现出以过量电子跃迁为主的大的非线性光学响应，对于自由基离子对盐M-2（中心点+）TCNQ（中心点-），其静态第一超极化率（β（0））较大.β（0）值的顺序为19203（M = Li）<24140（M = Na）<29065a.u.（M = K）。特别地，首次得到了具有过剩电子的配合物的第二超极化率（γ（0））。这些静态第二超极化率也很大。γ（0）值的大小顺序为2213006（M = Li）<3136754（M = Na）<7905623 a。联合（M = K）。在这三种结构中，K-2（中心点+）TCNQ（中心点-）具有最大的伽马（0）值，为7.9 × 10（6）a.u. (3982 x10（~ 3 × 6 esu），其比分子内电荷转移络合物σ-芳基亚乙烯基反式[Ru（4-C= CHC 6 H4 CC 6 H4 NO2）Cl（dppm）（2）] PF 6的大约9倍[Hurst等人，Organometallics，2001，20，4664]。本研究为高性能非线性光学材料提供了一种新的候选材料。
The interesting radical ion pair salts M-2(center dot+) TCNQ(center dot-)(M = Li, Na, K) are a particular class of charge transfer complexes with excess electron. The ground states of these complexes are triplet. The C-2v symmetry geometrical structures of the M-2(center dot+) TCNQ(center dot-)(M = Li, Na, K) with all-real frequencies are obtained at the density functional theory (DFT) B3LYP/6-31+ G(d) level. All calculations of electric properties in this paper have been carried out at the restricted open-shell second order Moller -Plesset perturbation theory (ROMP2) level. Owing to existing excess electron (from the polarized alkali metal atoms) these charge transfer complexes exhibit large nonlinear optical (NLO) responses dominated by excess electron transitions.For these radical ion pair salts M-2(center dot+) TCNQ(center dot-), the static first hyperpolarizabilities (beta(0)) are large. The order of beta(0) values is 19 203 ( M = Li) < 24 140 ( M = Na) < 29 065 a.u. ( M = K). Specially, the second hyperpolarizability (gamma(0)) of the complexes with excess electron is obtained for the first time. These static second hyperpolarizabilities are also large. The order of gamma(0) values is 2 213 006 (M = Li) < 3 136 754 (M = Na) < 7 905 623 a. u. (M = K). Among the three structures, K-2(center dot+) TCNQ(center dot-) has the largest gamma(0) value to be 7.9 x 10(6) a.u. (3982 x 10(-3)6 esu), which is about 9 times larger than that of the intramolecular charge transfer complex sigma- arylvinylidene trans[Ru(4-C=CHC6H4C CC6H4NO2) Cl(dppm)(2)] PF6 [Hurst et al., Organometallics, 2001, 20, 4664]. The present investigation provides a new kind of candidates for the high-performance NLO materials.