Copper(I)-templated synthesis of [2]catenates bearing pendant porphyrins

The copper(I)-templated synthesis of the first [2]catenate incorporating electron-donor and -acceptor porphyrins linked mechanically, though not covalently, has been achieved, along with that of related model. compounds incorporating only electron donating zinc(Ir) porphyrins. The preparations were approached by first constructing macrocycles incorporating 2,9-diphenyl-1,10-phenanthroline residues and pendant porphyrins. An unusual aggregation of one of these macrocycles, incorporating a gold(III) porphyrin, has been observed and appears to be driven by pi-pi stacking interactions, but proves to be no impediment to the preparation of the catenates. The gross conformation of the catenates in solution seems to be approximately that of the envisaged design where the porphyrins are directed to opposite sides and laterally away from the heart of the catenate, since no inter-porphyrin interactions could be detected by NMR or UV-visible spectroscopy. The removal of the templating copper(I) ion from the catenates is inhibited by the presence of appended zinc(II) porphyrins, while the free catenands may be obtained when the zinc(II) ion is absent.