https://doi.org/10.1007/s100530050382
Dynamics of BF4- anion reorientation in the spin-crossover compound [Fe(14-n-propyl-1H-tetrazole)6](BF4)2 and in its ZnII analogue
1
Research Institute for Solid State Physics and Optics,
Hungarian Academy of Sciences, pob. 49, 1525 Budapest, Hungary
2
Department of Nuclear Chemistry, Eötvös University, Budapest, Hungary
3
Institut für Anorganische Chemie und Analytische Chemie,
Johannes-Gutenberg-Universität Mainz, Germany
Received:
9
February
1999
Revised:
14
June
1999
Published online: 15 December 1999
and 
spin-lattice relaxation times were measured
in 
and in the spin-crossover compound 
. For
both compounds 
anion reorientation is active above 50 K. For
, the anion-reorientation dynamics is
different in the temperature regions of 50-90 K, 90-120 K, and above 150 K;
between 120 and 150 K it changes rapidly reflecting a structural change. In
the mechanism for the paramagnetic
relaxation involving the nuclei is found to be of the
diffusion-limited type according to the theory of Lowe and Tse. The present
results prove that the spin-crossover takes place in a dynamic surrounding
and not in a static crystal lattice.
PACS: 33.15.Vb – Correlation times in molecular dynamics / 33.15.Hp – Barrier heights (internal rotation, inversion, rotational isomerism, conformational dynamics) / 33.25.+k – Nuclear resonance and relaxation
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999
