6 Molecular Magnetism of Metal Complexes and Light-Induced …
273
Fig. 6.5 Schematic demonstration of the erasable optical recording based on the LIESST and
reverse-LIESST for [Fe II (ptz) 6 ](BF 4 ) 2
shows the schematic demonstration of the erasable optical recording based on the
LIESST and reverse-LIESST for [Fe
II (ptz) 6 ](BF 4 ) 2 .
6.2.2 Dynamic Spin Crossover Phenomena
of A[M II Fe III (mto) 3 ] (A = Counter Cation; M = Zn,
Cd; mto = C 2 O 3 S)
In this section, we focus on the spin crossover phenomenon of Fe
III coordinated by
three S atoms and three O atoms, Fe
III O 3 S 3 . In general, the Fe
III site coordinated by
six S atoms tends to be in the LS state (t
5
2g , S = 1/2), while the Fe
III site coordinated
by six O atoms is in the HS state (t
3
2g e
2
g , S = 5/2). Therefore, the spin state of
Fe
III O 3 S 3 has a possibility to exhibit the spin-crossover phenomenon between the
LS and HS states, which is schematically shown in Fig. 6.6.
As a matter of fact, in the case of tris(monothio-β-diketonato)iron(III) complexes,
the LS (S = 1/2) and HS (S = 5/2) states coexist between 300 and 80 K, and two
kinds of quadrupole doublets corresponding to the LS and HS states are clearly
distinguished in the
57 Fe Mössbauer spectra, in which the component of LS state
increases with decreasing temperature from 300 to 80 K [18]. In the case of