Chemistry Reference
In-Depth Information
Fig. 9.8 1D chain structure of [Pt
2
(
n
-BuCS
2
)
4
I]
1
(4) at 167 K in the LT phase with an atomic
numbering scheme and relevant interatomic distances (thermal ellipsoid set at the 50 % probability
level) [
33
]
twist of PtS
4
planes between the adjacent diplatinum units in the 1D chain and the
difference in conformation of the ligands observed at RT phase disappeared in the
LT phase, and the periodicity of the crystal lattice in the 1D chain direction changes
from threefold of a -Pt-Pt-I- period in the RT phase to twofold in the LT phase.
Two Pt-Pt distances are almost
the same (Pt1-Pt2
¼
2.675(1) and Pt3-Pt4
2.677(1)
˚
), whereas there are two different Pt-I bond distances. The short
Pt-I distances (Pt2-I1
¼
2.906(1)
˚
) are about 0.07
˚
¼
2.889(1) and Pt3-I1
¼
2.987(1)
˚
).
Based on the observed Pt-Pt and Pt-I distances, the valence-ordered state in the
LT phase in 4 is assigned to be the ACP state of -Pt
2+
-Pt
3+
-I
-Pt
3+
-Pt
2+
-I
-.
the long Pt1-I2
0
¼
less than those of
2.939(1) and Pt4-I2
¼
9.2.3 X-Ray Photoelectron Spectra
As will be described in detail
later
in the Transport Properties section,
[Pt
2
(RCS
2
)
4
I]
1
(R
Me (1), Et (2)) undergo the metal-semiconductor transition
near 300 and 205 K, respectively. To examine the valence state of the platinum
atoms, the X-ray photoelectron spectra (XPS) measurements have been made on 1
and 2 [
31
,
32
]. The Pt 4f
7/2
and 4f
5/2
core level spectrum for 2 at room temperature
are shown in Fig.
9.9
, together with that of [Pt
2
II,II
(EtCS
2
)
4
]and[Pt
2
III,III
(EtCS
2
)
4
I
2
][
32
].
¼
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