TY - JOUR
T1 -
Study on the valence fluctuation and the magnetism of an iron mixed-valence complex, (n-C
4
H
9
)
4
N[Fe
II
Fe
III
(mto)
3
](mto = C
2
O
3
S)
AU - Kagesawa, Koichi
AU - Ono, Yuki
AU - Enomoto, Masaya
AU - Kojima, Norimichi
PY - 2009/6/22
Y1 - 2009/6/22
N2 -
In the case of iron mixed-valence complexes whose spin states are situated in the spin-crossover region, conjugated phenomena coupled with spin and charge are expected. In general, the Fe site coordinated by six S atoms is in the low-spin state, while the Fe site coordinated by six O atoms is in the high-spin state. From this viewpoint, we have synthesized and investigated physical properties for an monothiooxalato-bridged (mto = C
2
O
3
S) iron mixed-valence complex, (n-C
4
H
9
)
4
N[Fe
II
Fe
III
(mto)
3
], consisting of Fe
III
O
3
S
3
and Fe
II
O
6
octahedra, which behaves as a ferrimagnet with its magnetic transition temperature of T
N
= 38 K and Weiss temperature of θ = -93 K. From the analysis of
57
Fe Mössbauer spectra of
57
Fe enriched complexes, (n-C
4
H
9
)
4
N[
57
Fe
II
Fe
III
(mto)
3
] and (n-C
4
H
9
)
4
N[Fe
II57
Fe
III
(mto)
3
], the charge transfer between Fe
II
and Fe
III
exists in the paramagnetic phase. Considering the time window of
57
Fe Mössbauer spectroscopy, the time scale of the valence fluctuation is at least slower than 10
-7
s. In order to confirm the valence fluctuation between Fe
II
and Fe
III
, we investigated the dielectric constant and found an anomalous enhancement attributed to the Fe valence fluctuation between 170 and 250 K.
AB -
In the case of iron mixed-valence complexes whose spin states are situated in the spin-crossover region, conjugated phenomena coupled with spin and charge are expected. In general, the Fe site coordinated by six S atoms is in the low-spin state, while the Fe site coordinated by six O atoms is in the high-spin state. From this viewpoint, we have synthesized and investigated physical properties for an monothiooxalato-bridged (mto = C
2
O
3
S) iron mixed-valence complex, (n-C
4
H
9
)
4
N[Fe
II
Fe
III
(mto)
3
], consisting of Fe
III
O
3
S
3
and Fe
II
O
6
octahedra, which behaves as a ferrimagnet with its magnetic transition temperature of T
N
= 38 K and Weiss temperature of θ = -93 K. From the analysis of
57
Fe Mössbauer spectra of
57
Fe enriched complexes, (n-C
4
H
9
)
4
N[
57
Fe
II
Fe
III
(mto)
3
] and (n-C
4
H
9
)
4
N[Fe
II57
Fe
III
(mto)
3
], the charge transfer between Fe
II
and Fe
III
exists in the paramagnetic phase. Considering the time window of
57
Fe Mössbauer spectroscopy, the time scale of the valence fluctuation is at least slower than 10
-7
s. In order to confirm the valence fluctuation between Fe
II
and Fe
III
, we investigated the dielectric constant and found an anomalous enhancement attributed to the Fe valence fluctuation between 170 and 250 K.
KW - Iron mixed-valence complex
KW - Valence fluctuation
UR - http://www.scopus.com/inward/record.url?scp=66149171353&partnerID=8YFLogxK
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U2 - 10.1016/j.poly.2009.01.011
DO - 10.1016/j.poly.2009.01.011
M3 - Article
AN - SCOPUS:66149171353
SN - 0277-5387
VL - 28
SP - 1822
EP - 1825
JO - Polyhedron
JF - Polyhedron
IS - 9-10
ER -