Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK.
Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, UK.
Dalton Trans. 2022 Sep 20;51(36):13636-13645. doi: 10.1039/d2dt02142k.
The number of zeolitic imidazolate frameworks (ZIFs) that form melt-quenched glasses remains limited, with most displaying the network topology. Here, we expand our studies to topology ZIFs, starting with ZIF-zni [Zn(Im)] before changing its linker chemistry, by incorporating 2-methylimidazolate and 5-aminobenzimidazolate. ZIF-zni was found to melt and form a glass, with = 576 °C and = 322 °C, although it was not possible to prepare the glass without zinc oxide impurities. The addition of 2-methylimidazolate to the structure gave ZIF-61 [Zn(Im)(mIm)], which decomposed without passing through the liquid state. However, incorporating small quantities of 5-aminobenzimidazolate resulted in a ZIF [Zn(Im)(abIm)] with a lower melting temperature ( = 569 °C) than pure ZIF-zni, and no evidence of zinc oxide growth. This demonstrates the sensitivity of melting behaviour in ZIFs towards linker chemistry, with only a 0.25% variation capable of eliciting a 7 °C change in melting temperature. This study highlights the chemical sensitivity of melting in ZIFs and serves as a promising strategy for tuning their melting behaviour.
形成熔融淬火玻璃的沸石咪唑酯骨架（ZIF）的数量仍然有限，大多数显示出 拓扑结构。在这里，我们通过引入 2-甲基咪唑和 5-氨基苯并咪唑，将我们的研究扩展到拓扑 ZIF 上，从 ZIF-zni [Zn(Im)]开始，然后改变其连接体化学。发现 ZIF-zni 熔融并形成玻璃， = 576°C 和 = 322°C，尽管如果没有氧化锌杂质，就不可能制备出玻璃。将 2-甲基咪唑添加到结构中得到 ZIF-61 [Zn(Im)(mIm)]，它在不经过液态的情况下分解。然而，少量 5-氨基苯并咪唑的加入导致 ZIF [Zn(Im)(abIm)]的熔点（ = 569°C）低于纯 ZIF-zni，并且没有氧化锌生长的证据。这表明 ZIF 中熔融行为对连接体化学的敏感性，仅 0.25%的变化就能引起 7°C 的熔点变化。本研究强调了 ZIF 中熔融的化学敏感性，并为调节其熔融行为提供了一种有前途的策略。
