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Fig. 4.2
X-ray crystal structures of Q[7]/M
Alkaline earth
-based coordination polymers in the pres-
ence of [CdCl
4
]
2
−
anions:
a
representation of an overall view of the coordination feature and
the supramolecular assembly;
b
the [CdCl
4
]
2
−
anions honeycomb-like framework;
c
a zigzag
coordination polymer of Alkaline earth
2
+
cations to Q[7] molecules surrounded by the [CdCl
4
]
2
−
anions;
d
magnified SME image of the crystal-coated SPME fiber at 300 °C;
e
GC-FID chroma-
tograms of seven PAHs extracted by the novel fiber coated with crystal. Peaks: naphth alene (
1
);
acenaphthene (
2
); fluorene (
3
); phenanthrene (
4
); anthracene (
5
); fluoranthene (
6
); and pyrene
(
7
). Adapted from Ref. [
8
] with permission from The Royal Society of Chemistry
fiber consists of a supporting substrate and a thin layer of sorbent material. Fused-
silica fiber was used as the supporting substrate and the Q[7]-based porous crys-
tals were fixed to the surface of the fused-silica fiber using high-temperature
epoxy. The surface structure of the SPME was investigated by SEM, as shown in
Fig.
4.2
d. The micro-structured coating is rough, porous, roughly uniform, and
about 32
ʼ
m thick. The fiber was coupled to a gas chromatography unit and its
separation effectiveness was investigated using seven polycyclic aromatic hydro-
carbons (PAHs) in wastewater samples, in head-space mode (Fig.
4.2
e). The novel
fiber with its crystalline extraction coating exhibited excellent extraction efficiency
and stability. These experimental results suggest that such Q[7]-based coordina-
tion polymers could be applied to the analysis of trace PAHs in real water samples.
In fact, our laboratory is interested in studying the cucurbit[
n
]urils (Q[
n
is coordi-
nation chemistry [
4
], among which Q[
n
]-Ln
3
+
interaction chemistry is an important
part. Professor Zhu's group in our laboratory has focused on the Q[
n
]-Ln
3
+
-based
interaction chemistry and potential applications, and we have found that almost all
Q[
n
]s and their derivates can interact with lanthanide cations, in particular, Q[
n
]s
can easily coordinate with Ln
3
+
cations and form novel different coordination pol-
ymers and supramolecular assemblies in the presence of third species as structure
directing agents; the outer-surface interactions of Q[
n
]s are considered as the driving
forces [
5
]. More recently, we expanded the Q[
n
]-Ln
3
+
-based interaction chemistry
from construction of novel coordination polymers and supramolecular assemblies
to the isolation or separation of lanthanide cations based on the discovery of abil-
ity of Q[
n
]s to identify lanthanide cations, and plan to systematically investigate the
interactions of each of Q[
n
]s and their derivates with series of lanthanide cations,
and the potential applications of these Q[
n
]s in isolation or separation of lanthanide.
For example, the interactions between a series of lanthanide cations (Ln
3
+
) and a
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