The goal of the research ongoing in the Hansen lab is the preparation of self-assembling nanostructures of discrete size, a current challenge in the field of supramolecular chemistry. In particular, recent results reported by the Sanders group at the University of Cambridge are being extended to prepare both nanotubes and capsules that spontaneously assemble; naphthalene diimide (NDI) derivatives, in which the aromatic core is flanked by two amino-acid residues, serve as the building blocks. The specific approach taken by the Hansen lab is to preorganize the NDI monomers for nanotube and capsule formation through the introduction of covalent tethers. In future, the ends of the nanotubes will be capped by selective incorporation of NDI subunits that will not permit further self-assembly. To date the group has prepared six linked dimer derivatives, five of which have been demonstrated to form nanotubes, and has prepared a linked trimer that spontaneously forms capsules.
The work involved in the above projects entails organic synthesis of the derivatives under investigation and their analysis by nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopy.