Chemistry Reference
In-Depth Information
Fig. 9 The Mobius strip
approach to catenane
synthesis. The number of
half-twists in the strip
determine the topology of the
product after it is cut down
the middle. Two half-twists
would afford a [2]catenane.
Reproduced with permission
from [
54
] (copyright 1985
Elsevier)
subsequently also synthesized the one half-twist molecular M
obius strip. He
verified experimentally that two macrocycles are obtained by cutting the cylinder
in half by ozonolysis of the THYME double bonds, while the same action on the
M
€
€
obius strip leaves it in one piece as a larger macrocycle [
71
]. However, no double
half-twist M
€
obius strip that would lead to the [2]catenane has been reported to date.
Sauvage's game-changing publication [
72
] in 1983, which describes the use of a
copper(I) ion to template the formation of mechanically interlocked rings
(catenands), breathed new life into the field of MIMs in relation to their accessibility,
applicability, and even their structural portrayals. The early catenanes were
represented conceptually by basic line drawings like those in Fig.
9
, and their
structures were portrayed in condensed structural formulas, where hydrocarbons
assumed the C
x
H
y
constitutions and were connected with lines to other functional
groups (Fig.
8
). The result was a picture that sufficiently communicated atomic and
topological content, but bore little resemblance to what the actual structure might
look like. When Sauvage [
72
] revealed a skeletal diagram of his catenane (Fig.
10
),
the result was a structural drawing that was rich in beauty as well as topological and
molecular information. This diagram - hand-drawn in Indian ink - expressed most
elegantly the right information while still hinting at the three-dimensional nature of
the molecule. It has appeared many times over the years in the literature from
Sauvage's group and is a landmark picture of a catenane [
73
]. It is the gold standard
of a MIM drawing, saturated with information and easy to digest.
