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Fig. 3.15
(
Left
) coordination of hydroxyl groups on the outer surface of Q[n]s with metal ions;
(
right
) X-ray crystal structure
a
top view;
b
side view of (HO)
10
Q[5]/K
+
2D network;
c
of
+
+
(HO)
10
Q[5]/K
complex;
d
stacking of the (HO)
10
Q[5]/K
2D networks with honeycomb struc-
ture features
axis creates honeycomb-like supramolecular assemblies with infinite 1D channels
along the
a
axis, in which the Cl
−
counter ions and water molecules are entrapped.
(HO)
10
Q[5]/Cs
+
-based 2D networks show similar structure features as those in the
(HO)
10
Q[5]/K
+
-based 2D networks [
38
].
3.3 Induced Coordination Polymers of Cucurbit[6]urils
with Metal Ions
Recently, our lab also prepared a series of 1D polymers constructed from alkyl-
substituted Q[6]s with different metal ions. Among them are complexes of
TMeQ[6] with alkali and alkaline earth metal ions and their coordination polymers
[
39
]. As ligands, unsubstituted cucurbituril (Q[6]) or partially methyl-substituted
cucurbituril, TMeQ[6] can generally coordinate with either alkali or alkaline earth
metal ions and with certain complexes. However, the assembly of the complexes
of metal ions with Q[
n
]s could depend upon the Q[
n
] ligands. Previous experi-
mental results reveal that the unsubstituted Q[6] ligand can coordinate with alkali
metal ions and form a 1D supramolecular assembly of alternating Q[6] molecules
and metal ions through direct coordination (referring to Fig.
3.2
) [
7
-
9
]. The results
also reveal that the TMeQ[6] ligand can coordinate with the alkaline earth metal
ions and form a 1D supramolecular assembly of alternating TMeQ[6] molecules
and metal ions through direct coordination (Fig.
3.16
) [
39
]. The coordination
of Q[6] with alkaline earth metal ions also produces common 1D coordination
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