Chemistry Reference
In-Depth Information
Chapter 2
Simple Coordination Complexes
of Cucurbit[
n
]urils with Metal Ions
Abstract
Generally, the noncovalent interaction of Q[
n
]s with various guest
molecules has led to the development of Q[
n
]-based host-guest chemistry, which
has become the mainstream in Q[
n
] chemistry. In fact, the establishment of Q[
n
]
chemistry started with Q[
n
]-based coordination chemistry because the structural
characteristics of the first characterized member of the Q[
n
] family, Q[6], was
based on the determination of the complex of Q[6] molecules with Ca
2
+
cations.
From a structural viewpoint, the two preorganized (identical) carbonyl fringed
portals in Q[
n
]s are ideal for acting as a rigid platform for developing a variety
of Q[
n
]-metal derived coordination structures. In this chapter, a number of Q[
n
]-
based metallo-supramolecular coordination fashions and examples are reviewed
in detail. Overall, molecular bowls, molecular capsules, sandwich pairs, and het-
erometallic complexes are the general structures in the solid state. We therefore
describe them in this chapter as simple coordination complexes of Q[
n
]s with
metal ions.
Keywords
Cucurbit[
n
]urils
·
Coordination complexes
·
Metal ions, molecular
bowls
·
Molecular capsules
·
Sandwich pairs
·
Heterometallic complexes
It is well known that Q[
n
]s [
1
-
5
] readily coordinate with metal ions because of
their two open polar portals rimmed with carbonyl groups (referring to Scheme
abilities with metal ions, and various metal ions seem to show different affinities
for a specific Q[
n
]. Moreover, environmental factors, such as coordination geom-
etry or radius of metal ions, temperature, counter-anions, steric bulk, solvent,
metal-to-ligand ratio, and pH of the system, influence the coordination and supra-
molecular assemblies of a Q[
n
] with a certain metal ion.
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