Using geometric simulation software ‘GASP’ to model conformational flexibility in a family of zinc metal-organic frameworks

William J. Gee, Stephen Wells, Simon J Teat, Paul Raithby, Andrew Burrows

Research output: Contribution to journalArticlepeer-review

1 Citation (SciVal)

Abstract

Here, a new tripodal tricarboxylic acid ligand, 4,4'-(4'-(4'-carboxy-[1,1'-biphenyl]-4-yl)-[2,2':6',2''-terpyridine]-5,5''-diyl)-dibenzoic acid (H3cbt), was synthesised using a three-step convergent strategy. Subsequent reactions with zinc(II) nitrate hexahydrate yielded three metal-organic frameworks (MOFs). The three MOFs, [Zn(Hcbt)]·4DMF (1), [Zn(Hcbt)]·4DMSO·1.5H2O·DMF (2), and [Zn(Hcbt)]·2DMF·3H2O (3), each adopt flexible interdigitated 2D net topologies. Framework 1 has DMF-filled channels that retain porosity upon desolvation, with a measured BET surface area of 248 m2 g-1. Framework 2 possesses larger DMSO-containing channels that collapse upon desolvation, resulting in near-equivalent porosity values to framework 1. In silico calculations and topological considerations determined using the geometric simulation software GASP dictate that framework 2 can feasibly alter conformation to approximate 1, but cannot perfectly replicate the interdigitated motif. Framework 3 formed when wet solvents were used to synthesise 1. Interestingly, the interdigitated structure of 3 contains a unique carboxylate binding mode that precludes its subsequent adoption by either 1 or 2 upon their exposure to water. This diverse array of structural considerations recommends this MOF family for modelling using GASP. Interrogating frameworks 1–3 using this software provided insights that justified experimentally observed conformational trends, as well as barriers to interconversion between members of this MOF family. In a broader sense, this work demonstrates the wider applicability of GASP software to modelling structural changes within flexible MOF materials.
Original languageEnglish
Pages (from-to)8728-8737
Number of pages10
JournalNew Journal of Chemistry
Volume45
Issue number19
Early online date19 Apr 2021
DOIs
Publication statusPublished - 21 May 2021

Bibliographical note

Funding Information:
We are grateful to the EPSRC for financial support of the project (EP/K004956/1). We would also like to thank the ALS, LBNL for the beamtime to perform these measurements. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Keywords

  • structure analysis
  • Computational chemistry
  • chemistry

ASJC Scopus subject areas

  • Inorganic Chemistry

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