Deciphering the controlling factors for phase transitions in zeolitic imidazolate frameworks

Tao Du; Shanwu Li; Sudheer Ganisetti; Mathieu Bauchy; Yuanzheng Yue; Morten M Smedskjaer

doi:10.1093/nsr/nwae023

Deciphering the controlling factors for phase transitions in zeolitic imidazolate frameworks

Natl Sci Rev. 2024 Jan 13;11(4):nwae023. doi: 10.1093/nsr/nwae023. eCollection 2024 Apr.

Authors

Tao Du¹, Shanwu Li², Sudheer Ganisetti¹, Mathieu Bauchy³, Yuanzheng Yue¹, Morten M Smedskjaer¹

Affiliations

¹ Department of Chemistry and Bioscience, Aalborg University, Aalborg 9220, Denmark.
² Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton MI 49931, USA.
³ Physics of AmoRphous and Inorganic Solids Laboratory (PARISlab), Department of Civil and Environmental Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.

Abstract

Zeolitic imidazolate frameworks (ZIFs) feature complex phase transitions, including polymorphism, melting, vitrification, and polyamorphism. Experimentally probing their structural evolution during transitions involving amorphous phases is a significant challenge, especially at the medium-range length scale. To overcome this challenge, here we first train a deep learning-based force field to identify the structural characteristics of both crystalline and non-crystalline ZIF phases. This allows us to reproduce the structural evolution trend during the melting of crystals and formation of ZIF glasses at various length scales with an accuracy comparable to that of ab initio molecular dynamics, yet at a much lower computational cost. Based on this approach, we propose a new structural descriptor, namely, the ring orientation index, to capture the propensity for crystallization of ZIF-4 (Zn(Im)₂, Im = C₃H₃N₂^-) glasses, as well as for the formation of ZIF-zni (Zn(Im)₂) out of the high-density amorphous phase. This crystal formation process is a result of the reorientation of imidazole rings by sacrificing the order of the structure around the zinc-centered tetrahedra. The outcomes of this work are useful for studying phase transitions in other metal-organic frameworks (MOFs) and may thus guide the development of MOF glasses.

Keywords: glass formation; melting; metal-organic frameworks; phase transitions; ring orientation; transferable deep learning force field.