Chemistry Reference
In-Depth Information
4.2 Architectural Beauty
A synthetic chemist has the opportunity to share the same thrill as architects and
artisans, i.e., the pleasure of designing and building something new. We use the
term “architecture” to describe mechanically interlocked structures as we widen our
scope from mathematical topology to include topologically trivial species such as
rotaxanes. The field of MIMs is full of opportunities to create new and exotic
architectures like those shown in Figs.
22
&
23
. In Fig.
22
we acknowledge a
handful of MIMs whose architectures were unprecedented at the time of publica-
tion. Fig.
22a
is a “pretzelane,” a [2]catenane in which the two macrocycles are
covalently connected. The Vogtle group was the first to prepare a pretzelane [
143
,
149
] and has also applied a similar concept to rotaxanes: a [1]rotaxane [
150
] results
when the ring of a [2]rotaxane is connected to its dumbbell; a “molecular 8” [
151
]
O
O
a
b
O
O
O
O
O
O
O
O
O
O
N
N
O
O
N
N
Cu
+
O
Cu
+
N
S
N
HN
O
S
N
O
N
H
O
O
N
N
N
O
OMe
N
N
OMe
O
O
H
N
Cu
+
H
N
O
H
N
O
N
N
H
O
O
N
O
O
O
O
O
O
O
F
F
c
d
F
Si
O
O
H
N
2
H
N
2
O
N
N
F
F
F
O
F
F
F
O
O
Pd
Pd
O
N
O
N
H
2
F
F
N
H
2
O
O
O
N
O
O
N
N
F
F
O
O
F
F
O
O
N
N
F
F
O
O
F
O
O
O
H
N
2
H
N
2
O
O
O
O
O
N
Si
O
F
F
F
F
F
N
O
O
O
O
Pd
Pd
N
N
H
2
N
F
F
N
H
2
F
O
O
F
F
e
f
F
F
O
O
O
O
O
HN
NH
O
O
O
O
NH
2
+
N
O
O
N
NH
2
O
O
O
HN
O
O
NH
O
O
O
N
N
N
O
N
N
N
N
Cu
+
Cu
+
O
O
O
HN
O
N
N
N
O
NH
O
O
NH
2
+
N
N
NH
2
O
O
O
HN
NH
O
O
O
O
O
O
O
O
O
O
O
O
Fig. 22 Novel MIM architectures: (a) pretzelane [
143
], (b) macrobicyclic [4]catenane [
144
],
(c) rotacatenane [
145
], (d) cyclic [2]catenane dimer [
146
], (e) cyclic [4]rotaxane [
147
], and
(f) doubly threaded [2]catenane [
148
]
