Dynamical effects on the magnetic properties of dithiazolyl bistable materials.

نویسندگان

  • Sergi Vela
  • Mercè Deumal
  • Motoyuki Shiga
  • Juan J Novoa
  • Jordi Ribas-Arino
چکیده

The magnetic properties of molecule-based magnets are commonly rationalized by considering only a single nuclear configuration of the system under study (usually an X-ray crystal structure). Here, by means of a computational study, we compare the results obtained using such a static approach with those obtained by explicitly accounting for thermal fluctuations, and uncover the serious limitations of the static perspective when dealing with magnetic crystals whose radicals undergo wide-amplitude motions. As a proof of concept, these limitations are illustrated for the magnetically bistable 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA) material. For its high-temperature phase at 300 K, we show that nuclear dynamics induce large fluctuations in the magnetic exchange interactions (JAB) between spins (up to 1000% of the average value). These deviations result in a ∼20% difference between the 300 K magnetic susceptibility computed by explicitly considering the nuclear dynamics and that computed using the X-ray structure, the former being in better agreement with the experimental data. The unveiled strong coupling between JAB interactions and intermolecular vibrations reveals that considering JAB as a constant value at a given temperature (as always done in molecular magnetism) leads to a flawed description of the magnetism of TTTA. Instead, the physically relevant concept in this case is the statistical distribution of JAB values. The discovery that a single X-ray structure is not adequate enough to interpret the magnetic properties of TTTA is also expected to be decisive in other organic magnets with dominant exchange interactions propagating through labile π-π networks.

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منابع مشابه

Dynamical effects on the magnetic properties of dithiazolyl bistable materials† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c4sc03930k Click here for additional data file.

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عنوان ژورنال:
  • Chemical science

دوره 6 4  شماره 

صفحات  -

تاریخ انتشار 2015