Issue 5, 2019

Modulating proton diffusion and conductivity in metal–organic frameworks by incorporation of accessible free carboxylic acid groups

Abstract

Three multi-carboxylic acid functionalised ligands have been designed, synthesised and utilised to prepare the new barium-based MOFs, MFM-510, -511, and -512, which show excellent stability to water-vapour. MFM-510 and MFM-511 show moderate proton conductivities (2.1 × 10−5 and 5.1 × 10−5 S cm−1, respectively) at 99% RH and 298 K, attributed to the lack of free protons or hindered proton diffusion within the framework structures. In contrast, MFM-512, which incorporates a pendant carboxylic acid group directed into the pore of the framework, shows a two orders of magnitude enhancement in proton conductivity (2.9 × 10−3 S cm−1). Quasi-elastic neutron scattering (QENS) suggests that the proton dynamics of MFM-512 are mediated by “free diffusion inside a sphere” confirming that incorporation of free carboxylic acid groups within the pores of MOFs is an efficient albeit synthetically challenging strategy to improve proton conductivity.

Graphical abstract: Modulating proton diffusion and conductivity in metal–organic frameworks by incorporation of accessible free carboxylic acid groups

Supplementary files

Article information

Article type
Edge Article
Submitted
08 Jul 2018
Accepted
02 Nov 2018
First published
02 Nov 2018
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2019,10, 1492-1499

Modulating proton diffusion and conductivity in metal–organic frameworks by incorporation of accessible free carboxylic acid groups

P. Rought, C. Marsh, S. Pili, I. P. Silverwood, V. G. Sakai, M. Li, M. S. Brown, S. P. Argent, I. Vitorica-Yrezabal, G. Whitehead, M. R. Warren, S. Yang and M. Schröder, Chem. Sci., 2019, 10, 1492 DOI: 10.1039/C8SC03022G

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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