Effect of Mechanochemical Recrystallization on the Thermal Hysteresis of 1D Fe II -triazole Spin Crossover Polymers
2020; American Chemical Society; Volume: 59; Issue: 12 Linguagem: Inglês
10.1021/acs.inorgchem.9b03284
ISSN1520-510X
AutoresDavid Nieto‐Castro, Felipe A. Garcés‐Pineda, Andrea Moneo‐Corcuera, Breogán Pato‐Doldán, Francesc Gispert‐Guirado, J. Benet‐Buchholz, José Ramón Galán‐Mascarós,
Tópico(s)Lanthanide and Transition Metal Complexes
ResumoThe thermal hysteresis in the cooperative spin crossover (SCO) polymer [Fe(trz)(Htrz)2]n[BF4]n (1) has been tuned by a simple ball milling grinding process. Mechanical treatment affects the size and morphology of the crystallite domains, as confirmed by multiple complementary techniques, including ESEM, DLS, and PXRD data. Upon milling, the regular cubic shape particles recrystallize with slightly different unit cell parameters and preferential orientation. This macroscopic change significantly modifies the thermally induced SCO behavior, studied by temperature-dependent magnetic susceptibility, X-ray diffraction, and DSC analysis. Transition temperatures downshift, closer to room temperature, while hysteresis widens, when particle sizes are actually decreasing. We relate this counterintuitive observation to subtle modifications in the unit cell, offering new alternatives to tune and enhance SCO properties in this class of 1D-cooperative polymers.
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