Phase control in the modulated self-assembly of lanthanide MOFs of a flexible tetratopic bis-amide linker

Thom, A. J.R. , Regincós Martí, E., Pakamorė, I., Wilson, C. and Forgan, R. S. (2022) Phase control in the modulated self-assembly of lanthanide MOFs of a flexible tetratopic bis-amide linker. Zeitschrift fur Anorganische und Allgemeine Chemie, 648(18), e202200171. (doi: 10.1002/zaac.202200171)

Abstract

The targeted synthesis of phase-pure metal-organic frameworks (MOFs) is often complicated by the fact that a number of different products can result from the same metal-ligand combination. The self-assembly of lanthanide-based MOFs can be particularly challenging due to the versatile coordination chemistry of the f -block allowing for diverse coordination spheres with irregular geometries driven by steric effects. Herein we show that modulated self-assembly – the addition of small molecules to solvothermal synthesis in order to control pH and coordination equilibria – can control phase formation when preparing lanthanide MOFs from the tetratopic bis-(3,5-dicarboxyphenyl)terephthalamide ligand. We report 27 new MOFs, of which 21 are characterised by single crystal X-ray diffraction, that can be categorised into six structure types. The formation of different phases is largely driven by the contraction in ionic radius across the lanthanide series, but we show how careful choice of both solvent and modulator can influence reaction outcome. As an example, phase pure samples of three Gd MOFs of the same ligand can be selected by simply changing the modulator – acetic acid, benzoic acid, or nitric acid – used in closely related syntheses. These results show that modulation can control phase in f -block MOFs, just as in d -block MOFs, and provide design rules for uncovering structural diversity by carefully exploring the chemical parameter space of lanthanide MOFs.

• Item Type: Articles
• Additional Information: R.S.F. thanks the Royal Society for receipt of a URF, and the University of Glasgow and EPSRC (EP/N509668/1) for funding.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Wilson, Dr Claire and Regincos Marti, Miss Emma and Thom, Mr Alexander and Pakamore, Mr Ignas and Forgan, Professor Ross
• Authors: Thom, A. J.R., Regincós Martí, E., Pakamorė, I., Wilson, C., and Forgan, R. S.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Zeitschrift fur Anorganische und Allgemeine Chemie
• Publisher: Wiley
• ISSN: 0044-2313
• ISSN (Online): 1521-3749
• Published Online: 11 July 2022
• Copyright Holders: Copyright © 2022 The Authors
• First Published: First published in Zeitschrift fur Anorganische und Allgemeine Chemie 648(18): e202200171
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
172865		EPSRC DTP 16/17 and 17/18	Mary Beth Kneafsey	Engineering and Physical Sciences Research Council (EPSRC)	EP/N509668/1	Research and Innovation Services