Markey Karen, Krüger Martin, Seidler Tomasz, Reinsch Helge, Verbiest Thierry, De Vos Dirk E, Champagne Benoît, Stock Norbert, van der Veen Monique A
Centre for Surface Chemistry and Catalysis, Faculty of Bioscience Engineering, University of Leuven, 3001 Leuven, Belgium.
Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, 24118 Kiel, Germany.
J Phys Chem C Nanomater Interfaces. 2017 Nov 16;121(45):25509-25519. doi: 10.1021/acs.jpcc.7b09190. Epub 2017 Oct 17.
-Nitroaniline presents the typical motif of a second-order nonlinear optically (NLO) active molecule. However, because of its crystallization in an antiparallel and hence centrosymmetric structure, the NLO activity is lost. In this contribution, the -nitroaniline motif was built successfully into the MIL-53 metal-organic framework. More precisely, MIL-53 was synthesized with 2-amino-5-nitroterephthalate as organic linker, with Al, Ga, or In as inorganic cation. The Al and Ga structures are polar, as confirmed by second-harmonic generation microscopy, yielding stable NLO materials. Indeed, they contain a 22-36% surplus of the dipolar 2-amino-5-nitro-terephthalate oriented in a parallel fashion. The indium compound was shown to be less crystalline and centrosymmetric. Ab initio modeling of the second-order NLO response shows that the Al and Ga materials show a response comparable to typical inorganic commercial NLO materials such as KDP. As a hybrid material, capable of low-temperature synthesis and processing and the ultrafast NLO responses associated with organic materials, this material can potentially provide an interesting venue for applications with respect to traditional inorganic NLO materials.
-硝基苯胺呈现出二阶非线性光学（NLO）活性分子的典型结构。然而，由于其以反平行且因此具有中心对称的结构结晶，NLO活性丧失。在本研究中，-硝基苯胺结构成功地构建到了MIL-53金属有机框架中。更确切地说，以2-氨基-5-硝基对苯二甲酸为有机连接体、以铝、镓或铟为无机阳离子合成了MIL-53。如通过二次谐波产生显微镜所证实的，铝和镓结构是极性的，从而产生稳定的NLO材料。实际上，它们含有22%至36%过量的以平行方式取向的偶极2-氨基-5-硝基对苯二甲酸。铟化合物显示出结晶性较差且为中心对称。二阶NLO响应的从头算模型表明，铝和镓材料显示出与典型无机商业NLO材料（如磷酸二氢钾）相当的响应。作为一种能够进行低温合成和加工以及具有与有机材料相关的超快NLO响应的混合材料，这种材料相对于传统无机NLO材料而言，有可能为应用提供一个有趣的途径。
