Abstract
Jahn-Teller (JT) distorted CuII-containing compounds often display interesting structural and functional behaviour upon compression. We use high-pressure X-ray and neutron diffraction to investigate four JT-distorted Prussian blue analogues: Cu[Co(CN)6]0.67, CuPt(CN)6, and ACuCo(CN)6 (A = Rb, Cs), where the first two were studied in both their hydrated and dehydrated forms. All compounds are less compressible than the JT-inactive MnII-based counterparts, indicating a coupling between the electronic and mechanical properties. The effect is particularly strong for Cu[Co(CN)6]0.67, where the local JT distortions are uncorrelated (so-called orbital disorder). This sample amorphises at 0.5 GPa when dehydrated. CuPt(CN)6 behaves similarly to the MnII-analogues, with phase transitions at around 1 GPa and low sensitivity to water. For ACuCo(CN)6, the JT distortions reduce the propensity for phase transitions, although RbCuCo(CN)6 transitions to a new phase (P2/m) around 3 GPa. Our results have a bearing on both the topical Prussian blue analogues and the wider field of flexible frameworks.
| Original language | English |
|---|---|
| Pages (from-to) | 3155-3164 |
| Number of pages | 10 |
| Journal | Chemical Science |
| Volume | 15 |
| Issue number | 9 |
| DOIs | |
| State | Published - Jan 23 2024 |
Funding
We are grateful to Diamond Light Source and STFC for provision of the beamtimes CY30164, CY30055, and RB2220172.59 HLBB acknowledges financial support from the Alexander von Humboldt Foundation, the Swedish Research Council (VR) with grant number 2022-02984, and the Wallenberg Initiative Materials Science for Sustainability (WISE) funded by the Knut and Alice Wallenberg Foundation. B. V. Lotsch (MPI-FKF, Germany) and A. L. Goodwin (Oxford, UK) are gratefully acknowledged for the use of lab space and M.-L. Schreiber (MPI-FKF, Germany) for ICP measurements.