QBIS Group, Departament de Química, Institut de Química Computacional I Catàlisis (IQCC), Universitat de Girona, Campus Montilivi, E17071 Girona, Catalonia, Spain.
Chemistry. 2013 Jan 21;19(4):1445-56. doi: 10.1002/chem.201203376. Epub 2012 Dec 4.
The metal-directed supramolecular synthetic approach has paved the way for the development of functional nanosized molecules. In this work, we report the preparation of the new nanocapsule 3·(CF(3)SO(3))(8) with a A(4 B(2) tetragonal prismatic geometry, where A corresponds to the dipalladium hexaazamacrocyclic complex Pd-1, and B corresponds to the tetraanionic form of palladium 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (2). The large void space of the inner cavity and the supramolecular affinity for guest molecules towards porphyrin-based hosts converts this nanoscale molecular 3D structure into a good candidate for host-guest chemistry. The interaction between this nanocage and different guest molecules has been studied by means of NMR, UV/Vis, ESI-MS, and DOSY experiments, from which highly selective molecular recognition has been found for anionic, planar-shaped π guests with association constants (K(a)) higher than 10(9) M(-1) , in front of non-interacting aromatic neutral or cationic substrates. DFT theoretical calculations provided insights to further understand this strong interaction. Nanocage 3·(CF(3)SO(3))(8) can not only strongly host one single molecule of M(dithiolene)(2) complexes (M=Au, Pt, Pd, and Ni), but also can finely tune their optical and redox properties. The very simple synthesis of both the supramolecular cage and the building blocks represents a step forward for the development of polyfunctional supramolecular nanovessels, which offer multiple applications as sensors or nanoreactors.
金属导向的超分子合成方法为功能纳米分子的发展铺平了道路。在这项工作中，我们报告了具有 A(4 B(2)四方棱柱几何形状的新型纳米胶囊 3·(CF(3)SO(3))(8)的制备，其中 A 对应于双钯六氮大环配合物 Pd-1，而 B 对应于钯 5,10,15,20-四(4-羧基苯基)卟啉 (2)的四阴离子形式。内腔的大空隙空间和超分子对基于卟啉的主体的客体分子的亲和力将这种纳米级分子 3D 结构转化为主体-客体化学的良好候选物。通过 NMR、UV/Vis、ESI-MS 和 DOSY 实验研究了纳米笼与不同客体分子之间的相互作用，从中发现了对阴离子、平面形状的π客体具有高度选择性的分子识别，其结合常数 (K(a))高于 10(9) M(-1)，而对非相互作用的芳香族中性或阳离子底物则没有。DFT 理论计算提供了进一步理解这种强相互作用的见解。纳米笼 3·(CF(3)SO(3))(8)不仅可以强烈容纳单个 M(dithiolene)(2)配合物 (M=Au、Pt、Pd 和 Ni)的分子，还可以精细调节它们的光学和氧化还原性质。超分子笼和构建块的非常简单的合成代表了多功能超分子纳米容器发展的一个进步，这些纳米容器具有作为传感器或纳米反应器的多种应用。
