M.Sc. Anja Heimann

Research topic: switchable three dimensional networks based on zwitterions

Supramolecular chemistry is a modern branch of the organic chemistry and deals with the reversible association of molecules by non-covalent interactions. Our research group combines these interactions to a guanidiniocarbonylpyrrolecarboxylate-zwitterion (Fig. 1). One special feature of this molecule is that its self-aggregation can be reversibly switched on and off by pH adjustmentsits reversible on/off-switch of aggregation caused by changes of the pH-value.

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Figure 1: dimer of the guanidiniocarbonylpyrrolecarboxylate-zwitterion

To get three dimensional networks several zwitterions have to be connected by a rigid centre. This is in the most cases an aromatic system with several amino or hydroxide groups (for example methanetetrayltetraaniline).

Because of the pH-dependence of the zwitterion it is possible to switch the formation of three dimensional networks on and off.

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Figure 2: scheme of the molecules and of the network