Pressure-Induced Unexpected Stabilization of the High-Spin State of Iron(II) in a Metal-Organic Framework
[EN] The effect of hydrostatic pressure on the spin state of the metal organic framework {Fe(R-pbpy+)2[mu 2-M(CN)4]2<middle dot>2H2O} (pbpy = phenylbipyridinium, R = CH3, M = Pd) was investigated by Raman spectroscopy and single crystal X-ray diffraction (SC-XRD). As expected, the appl...
| Autores: | , , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | inglés |
| OAI Identifier: | oai:riunet.upv.es:10251/231117 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/231117 |
| Access Level: | acceso embargado |
| Palabra clave: | Spin crossover Metal-organic frameworks Hydrostatic pressure Pressure-induced spin transition Electron transfer Spin states |
| Sumario: | [EN] The effect of hydrostatic pressure on the spin state of the metal organic framework {Fe(R-pbpy+)2[mu 2-M(CN)4]2<middle dot>2H2O} (pbpy = phenylbipyridinium, R = CH3, M = Pd) was investigated by Raman spectroscopy and single crystal X-ray diffraction (SC-XRD). As expected, the application of a hydrostatic pressure of 1.2 GPa fully transforms the high-spin (S = 2) ferrous ions into the low-spin (S = 0) form. Surprisingly, further increase of the pressure to 2.0 GPa induces a pressure-driven return to the S = 2 state, which can be switched again to the S = 0 state at 2.5 GPa. This unusual sequence of pressure-driven spin-state transitions is completely reversible and is also observable in two analogous compounds with M = Pt and R = Br. High-pressure X-ray crystal structure analysis reveals concurrent pressure-driven structural changes, assigned to an electron transfer (ET) process between the redox-active ligands. These processes cause a simultaneous elongation of the metal-ligand bond lengths and a contraction of the lattice volume, stabilizing, thus, the high-spin state in the pressure range of ca. 1.5-2.3 GPa, opposite to classical thermodynamics of spin crossover. |
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