Chemistry Reference
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Fig. 3.18
X-ray crystal structures of a 1D polymer synthesized through direct coordination of
Q[6] molecules and
a
Ce
3
+
−
anions;
b
Gd
3
+
cations in the presence of ReO
4
cations in the pres-
−
anions; and
c
Nd
3
+
ence of ReO
4
cations in the presence of 3-sulfobenzoate
from Sr
2
+
ions with Q[6]s, which are 1D polymeric. Two independent Sr
2
+
ions
are bound to each portal of the Q[6] molecule, one is being bound to two car-
bonyl groups and the other to only one. Thus, each cation is bound to three car-
bonyl groups from two Q[6] molecules. The coordination sphere of both Sr
2
+
ions
also includes the coordinated DMF molecule (Fig.
3.19
a, b). Moreover, these 1D
coordination polymers are separated from one another and surrounded by the cor-
rugated 2D uranyl organic networks (Fig.
3.19
c-e). In the 2D network, four inde-
pendent uranyl ions that comprise two centrosymmetric, bis(
ʼ
3
-oxo)-centered
tetranuclear clusters, are present in the complex; these two clusters can be consid-
ered to be isomorphous. Each of the two groups of atoms, U1 and U2 and U3 and
U4 is bound to one chelating, one bridging tridentate, and one bridging bidentate
carboxylate group (Fig.
3.19
f).
In Q[
n
]-based coordination chemistry and Q[
n
]-based host-guest coordina-
tion chemistry, there are supramolecular assemblies in which the Q[
n
]s are linked
by clusters or coordination units through direct coordination; these assemblies
form coordination polymers. In one of Thuery's works, a 1D coordination poly-
mer was obtained by mixing Q[6] and UO
2
(NO
3
)
2
6H
2
O with or without for-
mic acid under hydrothermal conditions (Fig.
3.20
a) [
44
]. In the 1D coordination
polymer, the uranyl ions form a centrosymmetric,
ʼ
3
-oxo-bridged tetranuclear
cluster (Fig.
3.20
b), and the U1 atom is bound to a Q[6] carbonyl group (O10).
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