Rotaxanes aromatic donor-acceptor interactions

Supramolecular chemistry is concerned with assemblies of molecules held together by non-covalent forces, such as hydrogen bonds, donor-acceptor interactions between aromatic stacks, ion-ion, ion-dipole, dipole-dipole and van der Waals attractions [1, 2]. Molecules can also be gathered around a metal this is the realm of coordination chemistry. Last, molecules can be linked together without the need for any chemical bond the so-called physical or mechanical bond is found in catenanes (species formed of interlocked rings) and rotaxanes (Figure 1). 

Stoddart and co-workers also made use of aromatic electron donor-acceptor (EDA) interactions for highly effective synthesis of catenanes and rotaxanes (Figure 1-3) [62]. In this case, however, one of the ligsons acts as template, which is subsequently incorporated in the covalent structure of the ligand product (catenane or rotaxane). 

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