Vibronic Model for Cooperative Spin-Crossover in Pentanuclear {[MIII(CN)6]2[MII(tmphen)2]3} (M/M = Co/Fe, Fe/Fe) Compounds Academic Article uri icon

abstract

  • In this paper we present a microscopic model for the cooperative spin-crossover (SCO) phenomenon in crystals containing cyano-bridged pentanuclear clusters {[MIII(CN)6]2[M II(tmphen)2]3} (M/M= Co/Fe, 1; Fe/Fe, 2) with a trigonal bipyramidal (TBP) structure. The low-spin to high-spin (ls-hs) transition is considered as a cooperative phenomenon that is driven by the interaction of electronic shells of FeII ions with totally symmetric deformation of the local environment that is extended over the crystal lattice via the acoustic phonon field. Due to proximity of FeII ions in the cluster, the short-range intracluster interaction between these ions via the optical phonon field is included as well. The model takes into consideration also the spin-orbit coupling operating within the cubic 5T 2(t24e2) term of the hs-FeII ions. For cluster 2 the Heisenberg-type exchange interaction between the hs-Fe II and ls-FeIII ions is taken into account. The competition between short- and long-range interactions is shown to determine the type and temperature of the SCO transition in cluster systems. The proposed model explains, in a unique way, the temperature dependence of the static magnetic susceptibility and the Mssbauer spectra of the title compounds. The approach described in this paper represents a theoretical tool for the study of spin-crossover systems based on metal clusters. 2011 American Chemical Society.

published proceedings

  • The Journal of Physical Chemistry C

author list (cited authors)

  • Klokishner, S., Ostrovsky, S., Palii, A., Shatruk, M., Funck, K., Dunbar, K. R., & Tsukerblat, B.

citation count

  • 17

complete list of authors

  • Klokishner, Sophia||Ostrovsky, Serghei||Palii, Andrei||Shatruk, Michael||Funck, Kristen||Dunbar, Kim R||Tsukerblat, Boris

publication date

  • October 2011