Chemistry Reference
In-Depth Information
Figure 7.4 (a) MSPs composed of ditopic phenanthroline ligands (1a and 1b) complexed to
Ag
I
or Cu
I
ions. (b) Schematic representation of the solvent displacement mechanism of MSP
dissociation and chain mixing (Lahn and Rehahn 2001).
of the ligand from the metal ion. In an elegant demonstration of the effects of solvent
on the dynamic behavior of these systems, two different polymers were mixed
together: 1a
.
AgBF
4
and 1b
.
CuPF
6
. This system appeared to be stable in TCE-d
2
for at least 3 days, showing no significant interchange of components. However,
upon the addition of acetonitrile, exchange processes occurred, resulting in the for-
mation of mixed copolymers. These experiments highlight the important role of
the solvent in the dissociation/exchange mechanism of MSPs, adding a further
complication in determining if a metallopolymer exhibits dynamic, supramolecular
behavior. For example, this system could be considered an MSP in acetonitrile;
however, it does not show supramolecular behavior in the noncoordinating solvent.
The dynamic nature of the metal -ligand bond is of course one of the key features
of MSPs. What makes these systems even more versatile from this point of view is
