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Fig. 3.29
X-ray crystal structures of the isolated Q[7]/Ln
3
+
complex with
a
and
b
the zigzag
structures;
c
and
d
the tubular structures in the presence of the [CdCl
4
]
2
−
dianions
[(UO
2
)
2
(
ʼ
2
-OH)
2
(H
2
O)
4
]
2
+
cation in the 2D coordination network (Fig.
3.32
b, c).
The 2D coordination network may be viewed as resulting from the bridging of the
[(UO
2
)
2
(
ʼ
2
-OH)
2
(H
2
O)
4
]
2
+
cations by the Q[7] ligands.
In order to understand the influence of an included guest on the coordination of
metal ions to Q[
n
], a series of aromatic molecules known to be suitable guests may
be selected [
52
-
54
]. We describe in detail a novel 3D framework constructed from
Q[7] pairs through Hyq-induced coordination of a rubidium unit to the portal oxy-
gens of Q[7]s [
55
]. To the best of our knowledge, this is the first observed Q[7]-
based 3D framework in Q[
n
] chemistry. Attempts of mixing Q[7] and rubidium
salts in aqueous solutions did not result in the formation of the Rb-Q[7] complex
through direct coordination, but instead produced Q[7] crystals with free metal
ions. However, a compound containing a novel 3D framework was first found
when a guest Hyq was introduced into the RbCl-Q[7] solution. Crystals obtained
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