Issue 37, 2023

The effect of inert dopant ions on spin-crossover materials is not simply controlled by chemical pressure

Abstract

[Fe(bpp)2][BF4]2 (bpp = 2,6-bis{pyrazol-1-yl}pyridine) undergoes abrupt thermal spin-crossover (SCO) at 261 K with a small 2–3 K thermal hysteresis. Different compositions of doped materials [FezZn1−z(bpp)2][BF4]2 and [FezRu1−z(bpp)2][BF4]2 (0 < z < 1) show similar broadening of the SCO transition with increased doping, but differ in their effect on the transition temperature. Doping with zinc strongly lowers T½, which is consistent with previous work. In contrast, doping with ruthenium increases T½ to a smaller degree, which cannot be explained by the chemical pressure arguments that are conventionally applied to doped SCO materials. Mechanoelastic simulations imply that different dopants exert opposite effects on the lattice elastic interactions in the material during the SCO transition. Consistent with that, the materials show a complicated dependence of the crystallographic lattice parameters and thermal expansion properties on the iron spin state, for different dopant ions. These changes correlate with small perturbations to the molecular structure of high-spin [Fe(bpp)2]2+, in the presence of dopants with different geometric preferences and conformational rigidities. We conclude the effect of isomorphous dopants on T½ reflects how the dopant influences the coordination geometry of the iron centres, as well as the chemical pressure exerted by the dopant ion size.

Graphical abstract: The effect of inert dopant ions on spin-crossover materials is not simply controlled by chemical pressure

Supplementary files

Article information

Article type
Paper
Submitted
28 Jul 2023
Accepted
29 Aug 2023
First published
30 Aug 2023
This article is Open Access
Creative Commons BY-NC license

J. Mater. Chem. C, 2023,11, 12570-12582

The effect of inert dopant ions on spin-crossover materials is not simply controlled by chemical pressure

P. Ghosh, C. M. Pask, H. B. Vasili, N. Yoshinari, T. Konno, O. Cespedes, C. Enachescu, P. Chakraborty and M. A. Halcrow, J. Mater. Chem. C, 2023, 11, 12570 DOI: 10.1039/D3TC02683C

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements