Construction of novel unsaturated cyclophanes with π-cavitand structure

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In this research, design and synthesis of novel unsaturated cyclophanes with caged structure was planned in order to investigate the unique electronic structure and to examine the possibility of the supramolecular chemistry based on the cavity surrounded with π-electrons.Hexabenzo[24]annulene, which is a macrocyclic benzannulene composed of six o-phenylenes and six cis-ethylene bridges, was probed to adopt a ‘self-filled' structure, where three alternate arene rings were located inside of the cavity. This energy-minimum structure was observed at low temperature in the solution as well as in the solid state. The preference of the conformer was ascribed to the cyclic concurrent CH-π interaction among the inside three benzene rings.Theoretical calculations for unsaturated deltaphanes, which was designed here, suggested the unique electronic properties : the compounds should have low reduction potential and the corresponding anions should have fully delocalized structure. Therefore, many methodologies for the synthesis of the. compounds were examined. Although the synthesis was not achieved, effective synthetic methods for the related compounds have been developed. These method will be applied for many other structurally interesting compounds.These results will provide new aspects for the research of new carbon conjugated systems including fullerenes, which are expected to be unique materials in nanotechnology applications.