Porous Metal–Organic Frameworks with Multiple Cages Based on Tetrazolate Ligands: Synthesis, Structures, Photoluminescence, and Gas Adsorption Properties

Three tetrazolate-based coordination polymers [Mn­(TzA)­(H2O)2]n (1, H2TzA = 1H-tetrazole-5-acetic acid),
{[Cd5(MTz)9]·OH}n (2, MTz = 5-methyltetrazolate), and
[Cd3(MTz)3Cl3]n (3) were synthesized via the reactions of a tetrazole
ligand
H2TzA with metal ions under hydrothermal conditions. During
the formation of 2 and 3, Cd­(II) ions were
coordinated by MTz–, which was generated as the
result of the in situ decarboxylation of the H2TzA ligand.
Single-crystal X-ray diffraction analyses revealed that 1 possessed an infinite 2D layer structure with a μ3-TzA2– moiety, forming a 44-sql topology, and the 2D sheets were further hydrogen-bonded to form
a 3D framework. Compound 2 had a 3D porous framework
with a 49·66-acs topology. Compound 3 adopted a 3D porous
framework with a body-centered cubic (bcu) topology,
which was comprised of 48-membered (Cd24Cl24) rings, and it demonstrated a moderate adsorption of H2 over N2 as a result of its limited window size. The solid-state
luminescent properties of complexes 2 and 3 and the corresponding HMTz molecule were also investigated.

三种基于四氮唑配位的聚合物 [Mn-(TzA)-(H2O)2]n (1, H2TzA = 1H-四氮唑-5-乙酸)， {[Cd5(MTz)9]·OH}n (2, MTz = 5-甲基四氮唑)，以及 [Cd3(MTz)3Cl3]n (3) 均通过在高温高压条件下将四氮唑配体 H2TzA 与金属离子反应合成。在 2 和 3 的形成过程中，Cd(II) 离子通过与 MTz– 配位，MTz– 是通过 H2TzA 配体的原位脱羧反应生成的。单晶 X 射线衍射分析显示，1 具有无穷的二维层状结构，其中含有 μ3-TzA2– 基团，形成 44-sql 拓扑，二维层通过氢键进一步结合形成三维框架。化合物 2 拥有 3D 多孔框架，具有 49·66-acs 拓扑。化合物 3 采用了具有体心立方 (bcu) 拓扑的 3D 多孔框架，由 48 员的 (Cd24Cl24) 环组成，由于其有限的窗口尺寸，它在 N2 上表现出对 H2 的适度吸附。同时，对复合物 2 和 3 及其相应的 HMTz 分子的固态发光性质也进行了研究。