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Temperature‐ and Pressure‐Induced Switching of the Molecular Spin State of an Orthorhombic Iron(III) Spin‐Crossover Salt
Author(s) -
Tissot Antoine,
Shepherd Helena J.,
Toupet Loic,
Collet Eric,
Sainton Joelle,
Molnár Gabor,
Guionneau Philippe,
Boillot MarieLaure
Publication year - 2013
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201201059
Subject(s) - spin crossover , chemistry , orthorhombic crystal system , isostructural , raman spectroscopy , crystallography , spin states , hydrostatic pressure , ambient pressure , spin transition , crystal structure , anisotropy , inorganic chemistry , thermodynamics , physics , quantum mechanics , optics
The [(TPA)Fe III (TCC)] + complex [TPA = tris(2‐pyridylmethyl)amine, TCC 2– = 3,4,5,6‐tetrachlorocatecholate dianion] forms a molecular solid with the SbF 6 – anion, which exhibits an incomplete S = 1/2 ↔ S = 5/2 thermal spin‐crossover process centered at 250 K. Single‐crystal X‐ray diffraction, Raman spectroscopy, and magnetic measurements of this orthorhombic polymorph were performed to delineate the spin‐state thermo‐ and piezoswitching in relation to the structural and elastic properties. Indeed, a pressure‐induced spin crossover (centered at P 1/2 ≈ 1.65 kbar, T = 294 K) concomitant with unit‐cell contraction was observed by applying a hydrostatic pressure to the single crystal. Under ambient conditions, the piezo‐induced transition, like that induced thermally, is relatively gradual, which probably reflects a similar mechanism in response to both stimuli. Except for a 47 K shift, the spin‐crossover curves of the isostructural SbF 6 – and PF 6 – salts compare well. They are discussed with respect to structural anisotropy and pressure effects.