Coordination polymers (CPs) are inherently modular because they are typically comprised of metal-based nodes and organic linker ligands. The resulting ability to control the pore size and pore chemistry results in CPs being of interest in storage, separation, and catalysis. CPs are generally synthesized by solution methods such as solvent diffusion and solvothermal methods; however, these methods can be time-consuming and lead to solvent waste. Mechanochemistry offers a greener and more sustainable approach, but it remains understudied in the context of CPs. This is especially the case for CPs, which contain 4,4′-bipyridine (bipy), the most widely used linker ligand. Herein, we compare the mechanochemistry vs slurry vs solution methods for the synthesis of five CPs formed by a 1:1 ratio of bipy and M^II(NO₃)₂·xH₂O, (M^II = Co, Ni, Zn, x = 6; M^II = Cu, x = 3; M^II = Cd, x = 4). We observed that ball milling and twin-screw extrusion both offer high-yield, low-waste routes to the same CP products prepared from solution, but the water slurry approach was found to be ineffective. The isolated CPs were found to exhibit high thermal stability (≥250 °C) and good compression resistance (≥350 bar). In addition, they have potential utility as sorbents for vapor separation or as precursors to form higher-dimensional CP structures.

中文翻译：

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机械化学与溶液法合成4,4'-联吡啶基配位聚合物的比较

配位聚合物（CPs）本质上是模块化的，因为它们通常由基于金属的节点和有机连接子配体组成。所产生的控制孔尺寸和孔化学性质的能力导致CP在存储，分离和催化方面引起关注。CP通常是通过诸如溶剂扩散和溶剂热法之类的溶液方法合成的。但是，这些方法可能很耗时并导致溶剂浪费。机械化学提供了一种更绿色，更可持续的方法，但在CP的背景下仍未对其进行研究。对于包含最广泛使用的连接子配体4,4'-联吡啶（bipy）的CP来说尤其如此。在这里，我们比较了机械化学法，浆液法和溶液法的合成方法，该方法合成了由1：1的Bipy和M ^II形成的5个CP （NO₃）₂ · x H ₂ O，（M ^II＝ Co，Ni，Zn，x＝ 6； M ^II＝ Cu，x＝ 3； M ^II＝ Cd，x＝ 4）。我们观察到球磨和双螺杆挤出均提供了从溶液制备的相同CP产品的高收率，低废料途径，但发现水浆法无效。发现隔离的CP具有较高的热稳定性（≥250°C）和良好的抗压缩性（≥350bar）。另外，它们具有潜在的用途，可用作蒸气分离的吸附剂或形成高维CP结构的前体。