Pressure‐Induced Spin‐Crossover Features at Variable Temperature Revealed by In Situ Synchrotron Powder X‐ray Diffraction. Issue 54 (3rd September 2018)

• Record Type: Journal Article
• Authors: Tailleur, Elodie; Marchivie, Mathieu; Itié, Jean‐Paul; Rosa, Patrick; Daro, Nathalie; Guionneau, Phillippe
• Is Part Of: Chemistry. Volume 24:Issue 54(2018)
• Page Start: 14495
• Page End: 14499
• Publication Date: 2018-09-03
• Subjects: bulk modulus -- high pressure -- powder diffraction -- Rietveld refinement -- spin-crossover; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201802828
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: An accurate high‐pressure X‐ray diffraction investigation, at various temperatures, on a powder of a spin‐crossover (SCO) complex has allowed the rare deconvolution of the structural features of the high‐spin and low‐spin phases. As a result, the pressure dependence of the structural parameters of the high‐spin and low‐spin phases can be discussed independently in the pressure domain where both phases co‐exist within the powder. Consequently, crucial unprecedented information is given, such as the variation of bulk moduli with temperature, similar here in amplitude for both spin phases, the temperature‐dependence of the pressure‐induced SCO abruptness, the temperature dependence of the pressure at which SCO occurs, and arguments for a possible piezo‐hysteresis. Performed on the molecular complex [Fe(PM‐PeA)2 (NCSe)2 ] (PM‐PeA= N‐ (2′‐pyridylmethylene)‐4‐(phenylethynyl) aniline), this study reveals a pressure‐induced SCO at 0.16 GPa and demonstrates that, when increasing temperature, the pressure of transition increases linearly, the abruptness of the pressure‐induced SCO strongly increases, and the bulk moduli decrease. Abstract : Pressure cooker : Fine tracking of the pressure‐induced spin crossover of a molecular complex was accomplished thanks to in situ PXRD under pressure. The independent determination of the behaviors of the HS and LS phases in the large pressure range of coexistence allows the extraction of information such as the bulk moduli of both phases.