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
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
A
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