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cc_2018_zncdzif8.pdf (1.43 MB)

Compositional Inhomogeneity and Tuneable Thermal Expansion in Mixed-Metal ZIF-8 Analogues

preprint
submitted on 25.05.2018, 12:21 and posted on 25.05.2018, 13:58 by Adam Sapnik, Harry Geddes, Emily Reynolds, Hamish Yeung, Andrew Goodwin
We study the structural and thermomechanical effects
of cation substitution in the compositional family of
metal–organic frameworks Zn1􀀀xCdx(mIm)2 (HmIm = 2-
methylimidazole). We find complete miscibility for all
compositions x, with evidence of inhomogeneous distributions of Cd and Zn that in turn affect framework aperture characteristics. Using variable-temperature X-ray powder diffraction measurements, we show that Cd substitution drives a threefold reduction in the magnitude of thermal expansion behaviour. We interpret this effect in terms of an increased density of negative thermal expansion modes in the more flexible Cd-rich frameworks.

History

Email Address of Submitting Author

andrew.goodwin@chem.ox.ac.uk

Institution

University of Oxford

Country

UK

ORCID For Submitting Author

0000-0001-9231-3749

Declaration of Conflict of Interest

No conflict of interest

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