A series of new alkali‐metal‐based coordination polymers, [Li(H₂IMDC)(H₂O)]_n (1), [Na₂(H₂IMDC)₂(H₃IMDC)₂(H₂O)₄]_n (2), and [K(H₂IMDC)(H₂O)]_n (3), have been constructed under solvothermal conditions by using imidazole‐4,5‐dicarboxylic acid (H₃IMDC) as ligand. The structure of the complexes has been determined by single‐crystal X‐ray diffraction and further characterized by elemental analyses, IR spectra, powder X‐ray diffraction and thermogravimetric analyses. The single crystal X‐ray structural studies showed that their structural dimensionalities varying from 1‐D zigzag chain, 2‐D 4⁴‐sql network to 3‐D 4,6‐connected coordination framework are strongly governed by the ionic radii and coordination geometries of the metal cations. For the first time, the alkali‐metal‐based coordination polymers were demonstrated to be effective catalysts for the solvent‐free ring‐opening polymerization (ROP) of ϵ‐caprolactone. The catalytic activity of complexes 1–3 depends on the metal cations, increasing in the order Li⁺ < Na⁺ < K⁺.

中文翻译：

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碱金属基咪唑羧酸酯配位聚合物的构建作为as-己内酯无溶剂开环聚合的有效催化剂

一系列新的基于碱金属的配位聚合物[Li（H ₂ IMDC）（H ₂ O）] _n（1），[Na ₂（H ₂ IMDC）₂（H ₃ IMDC）₂（H ₂ O）₄ ] _n（2）和[K（H ₂ IMDC）（H ₂ O）] _n（3），是在溶剂热条件下使用咪唑-4,5-二羧酸（H _3）合成的。IMDC）作为配体。配合物的结构已通过单晶X射线衍射确定，并通过元素分析，红外光谱，粉末X射线衍射和热重分析进一步表征。单晶X射线结构研究表明，其结构尺寸从1-D之字形链，2-D 4 ⁴ - sql网络到3-D 4,6连接的配位框架都受离子半径和配位几何形状的强力支配金属阳离子。首次证明了基于碱金属的配位聚合物是ϵ-己内酯的无溶剂开环聚合（ROP）的有效催化剂。配合物的催化活性1 - 3取决于金属阳离子，以Li ⁺ <Na ⁺ <K ⁺的顺序增加。