Chemistry Reference
In-Depth Information
Table 10.1 Selected interatomic distances and electronic state of MMX chains with binary
countercations
d
(Pt-I-Pt)/
˚
d
(Pt-I)/
˚
/
˚
Electronic state References
Complex
dð
Pt
I
Þ
K
2
(NC
3
N)[Pt
2
(pop)
4
I]
4H
2
O
5.6305(8)
2.641(3)
2.990(3)
ACP + CDW [
31
,
46
]
5.9786(9)
2.828(6)
3.151(6)
K
2
(Me-NC
3
N)[Pt
2
(pop)
4
I]
4H
2
O
5.7179(11)
2.7496(8)
2.9683(8)
ACP + CDW [
31
,
47
]
5.9254(11)
2.7993(7)
3.1261(8)
K
2
(Cl-NC
3
N)[Pt
2
(pop)
4
I]
4H
2
O
5.7262(11)
2.755(2)
2.951(2)
ACP + CDW [
31
,
46
]
5.9403(12)
2.8082(18) 3.1320(18)
K
2
(
cis
-NC
4
N)[Pt
2
(pop)
4
I]
4H
2
O
5.7625(18)
2.7430(9)
3.0195(10)
CDW
[
31
]
K
2
(
trans
-NC
4
N)[Pt
2
(pop)
4
I]
4H
2
O
5.7921(11)
2.732(3)
3.060(3)
CDW
[
31
]
K
2
(NC
5
N)[Pt
2
(pop)
4
I]
4H
2
O
5.7225(7)
2.729(9)
2.993(6)
CDW
[
31
]
K
2
(NC
2
OC
2
N)[Pt
2
(pop)
4
I]
4H
2
O
5.7244(11)
2.8757(6)
CDW
[
31
]
Rb
2
(NC
3
N)[Pt
2
(pop)
4
I]
4H
2
O
5.7521(5)
2.7430(3)
3.0091(4)
ACP + CDW [
31
]
6.1928(5)
2.8217(3)
3.3710(3)
Rb
2
(Me-NC
3
N)[Pt
2
(pop)
4
I]
4H
2
O
5.7782(7)
2.7478(5)
3.0304(4)
ACP + CDW [
31
]
6.1226(7)
2.8073(4)
3.3152(5)
Rb
2
(Cl-NC
3
N)[Pt
2
(pop)
4
I]
4H
2
O
5.7726(13)
2.7532(16) 3.0194(15)
ACP + CDW [
31
]
6.1518(13)
2.8155(16) 3.3363(16)
Rb
2
(
cis
-NC
4
N)[Pt
2
(pop)
4
I]
4H
2
O
5.8554(15)
2.735(5)
3.120(4)
CDW
[
31
]
Rb
2
(
trans
-NC
4
N)[Pt
2
(pop)
4
I]
2H
2
O 5.7930(9)
2.8965(4)
CDW
[
31
]
Rb
2
(NC
5
N)[Pt
2
(pop)
4
I]
4H
2
O
5.8219(15)
2.742(3)
3.080(3)
CDW
[
31
]
Rb
2
(NC
2
OC
2
N)[Pt
2
(pop)
4
I]
4H
2
O
5.823(2)
2.740(4)
3.097(4)
CDW
[
31
]
10.2.3 Origin of ACP-Like Distortion in ACP + CDW State
As mentioned above, only the MMX chains containing H
3
NCH
2
CHXCH
2
NH
3
2+
(X
H, Me, Cl) are in ACP + CDW state. Other MMX chains with binary
countercations containing longer B
2+
are in CDW state. To design the new elec-
tronic state of MMX chains in the future, revealing the mechanism of the ACP-like
distortion is very important.
In the most MMX chains with binary countercations, B
2+
mainly arranged along
b
-axis, resulting longer unit cell parameter
b
compared with
a
. Table
10.2
shows the
ratio
b
/
a
of all MMX chains with binary countercations. The electronic state
is ACP + CDW state when
b
/
a
¼
1.10, and is CDW state when
b
/
a
1.19.
Small
b
/
a
induces the steric hindrance around A
+
explained as follows:
Figure
10.4
shows the schematic representation of the 1D chain and its oxygen
atoms, lattice H
2
O molecules, A
+
and B
2+
. Ten oxygen atoms, eight from pop
ligands O(pop) and two from lattice H
2
O molecules (O(H
2
O)) exist around alkali
metal ion. When
b
/
a
1.10, because at most only eight oxygen atoms can coordi-
nate to A
+
, pop ligands twist to remove two O(pop) away from A
+
. On the other
hand, when
b
/
a
1.19, two O(pop) are initially far from A
+
without the twisting of
ligands. The distance between A
+
and coordinating O(pop) (
d
(A-O(pop))), and the
distance between A
+
and farther O(pop)
ðdð
A
O(pop))), are shown in Table
10.2
.
O(pop)) is longer than the sum of ionic radii of A
+
(1.65
˚
for K
+
and
1.75
˚
for Rb
+
)[
49
] and van der Waals radii of O atom (1.52
˚
), [
50
]no
coordination bond exist between these atoms.
Since
dð
A
Search WWH ::
Custom Search