Ultrahigh-field <sup>67</sup>Zn NMR reveals short-range disorder in zeolitic imidazolate framework glasses.

Madsen, Rasmus S K; Qiao, Ang; Sen, Jishnu; Hung, Ivan; Chen, Kuizhi; Gan, Zhehong; Sen, Sabyasachi; Yue, Yuanzheng · Science · 2020

basic_science · Level V

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Abstract

The structure of melt-quenched zeolitic imidazole framework (ZIF) glasses can provide insights into their glass-formation mechanism. We directly detected short-range disorder in ZIF glasses using ultrahigh-field zinc-67 solid-state nuclear magnetic resonance spectroscopy. Two distinct Zn sites characteristic of the parent crystals transformed upon melting into a single tetrahedral site with a broad distribution of structural parameters. Moreover, the ligand chemistry in ZIFs appeared to have no controlling effect on the short-range disorder, although the former affected their phase-transition behavior. These findings reveal structure-property relations and could help design metal-organic framework glasses.