Second-order nonlinear optical properties of trisubstituted Keggin and Wells-Dawson polyoxometalates: density functional theory investigation of the inorganic donor-conjugated bridge-acceptor structure.
Second-order nonlinear optical properties of trisubstituted Keggin and Wells-Dawson polyoxometalates: density functional theory investigation of the inorganic donor-conjugated bridge-acceptor structure.
复制标题
DOI：
10.1021/ic900829z
复制
发表时间：
2009-07
影响因子：
4.6
通讯作者：
Chun-Guan Liu;W. Guan;Ping Song;Z. Su;Chan Yao;E. Wang
中科院分区：
文献类型：
--
作者：
Chun-Guan Liu;W. Guan;Ping Song;Z. Su;Chan Yao;E. Wang
给体-共轭桥体-受体（D-A）模型作为一种简单的分子构型，已成功地应用于二级有机化合物、有机金属化合物和金属配合非线性光学（NLO）材料的研究。然而，对于完全无机的分子，这种模型的使用仍然是令人望而却步的。本文采用时变密度泛函理论（TDDFT）研究了钒、钼三取代Keggin和Wells-Dawson多金属氧酸盐（POMs）的二阶NLO性质。结果表明，这些聚甲醛簇具有D-A结构。在这些POM簇中，帽区的氧原子和另一帽区的金属（钒和钼）原子可以分别被视为电子的供体和受体。钒离子衍生物比钼离子衍生物具有更大的二阶NLO响应和偶极矩；因此，在我们的D-A方案中，帽区的三个钒原子作为与帽区的三个钼原子相关的强受体。具有well - dawson结构的钼钒酸盐由于其相关的长共轭桥和强受体而表现出良好的二阶NLO响应。该D-A模型可能是优化无机POM团簇第一超极化率的有效方法。
The donor-conjugated bridge-acceptor (D-A) model, as a simple molecular scheme, has been successfully used in the development of second-order organic compound, organometallic compound, and metal complex nonlinear optical (NLO) materials. However, for the totally inorganic molecules, the use of this model is still prohibitive. In the present paper, time-dependent density functional theory (TDDFT) was used to investigate the second-order NLO properties of vanadium- and molybdenum-trisubstituted Keggin and Wells-Dawson polyoxometalates (POMs). The results show that these POM clusters possess D-A structures. The oxygen atoms in the cap region and metal (vanadium and molybdenum) atoms in another cap region in these POM clusters can be viewed as the electron donor and acceptor, respectively. The vanadium ion derivatives possess larger second-order NLO responses and dipole moment than molybdenum ions derivatives; thus, the three vanadium atoms in the cap region act as a strong acceptor related to the three molybdenum atoms in cap region in our D-A scheme. The vanadomolybdate with Wells-Dawson structure displays the good second-order NLO response because of the relevant long conjugated bridge and strong acceptor. This D-A model may be an effective approach for optimizing the first hyperpolarizabilities of inorganic POM clusters.