Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
School of Chemistry and Molecular Biosciences, The University of Queensland-St. Lucia, St. Lucia, Queensland 4072, Australia.
Inorg Chem. 2020 Oct 19;59(20):15454-15459. doi: 10.1021/acs.inorgchem.0c02452. Epub 2020 Sep 30.
A two-dimensional molecular square () was obtained by the self-assembly of a bis(tetrazole) linker, 4,4'-bis(1-tetrazol-5-yl)-1,1'-biphenyl (H), with a square-planar metal acceptor [ = (tmeda)Pd(NO), where tmeda = ,,','-tetramethylethane-1,2-diamine] in dimethyl sulfoxide (DMSO) followed by crystallization. The uncommon 2,3-binding mode through N atoms of the tetrazole rings in this assembly leads to the formation of an octanuclear molecular square. The molecular square [Pd()(NO)] is unstable in DMSO and slowly converts to a dynamic mixture of a 3D tetrahedral cage [Pd()(NO)] and the macrocycle . A tetrahedral cage () is formed by the usual 1,3-binding mode of the tetrazole rings. However, self-assembly of the [Pd()(PF)] was possible to access in the pure form in a less polar solvent like acetonitrile. The pure [Pd()(PF)] also converts to a mixture of and in DMSO. Interestingly, when a tris(tetrazole) linker, tris(4-(1-tetrazol-5-yl)phenyl)amine (H), was treated with the acceptor , it produced a tetrahedral nanocage [Pd()(NO)] through 1,3-binding mode of the tetrazole rings without any trace of an octahedral cage through 2,3-binding mode of the tetrazole moieties.
由双（四唑）配体 4,4'-双（1-四唑基）-1,1'-联苯（H）与 square-planar 金属受体 [= (tmeda)Pd(NO)] 在二甲基亚砜（DMSO）中自组装，然后结晶得到二维分子正方形（）。在这个组装体中，四唑环的 N 原子通过不常见的 2,3-结合模式导致形成八核分子正方形。分子正方形[Pd()(NO)]在 DMSO 中不稳定，缓慢转化为 3D 四面体型笼[Pd()(NO)]和大环的动态混合物。四面体型笼()是通过四唑环的通常 1,3-结合模式形成的。然而，在非极性溶剂如乙腈中，以纯形式进行[Pd()(PF)]的自组装是可能的。纯[Pd()(PF)]在 DMSO 中也会转化为和的混合物。有趣的是，当使用三（四唑）配体三（4-(1-四唑基)苯基)胺（H）与受体反应时，它通过四唑环的 1,3-结合模式产生了四面体纳米笼[Pd()(NO)]，而没有任何八面体笼的痕迹通过四唑部分的 2,3-结合模式。
