Rings-and-string approach to the construction of porphyrin arrays by transition-metal-directed threading

Here, we describe an alternative principle for building multiporphyrinic assemblies. It is based on a transition-metal-directed threading reaction involving a two-chelate molecular string and two coordinating rings-each bearing a porphyrin as a pendant group-which thread and residue on the string by virtue of complexation to copper(I) ions. Results show that the modular string-and-rings approach is a viable one for constructing multiporphyrinic assemblies incorporating electron donor and acceptor chromophores between which there is no covalent link. In addition, once isolated, the complexes appear to exhibit relative kinetic stability, an observation that bodes well for the use of these and similar systems for the study of long-range electron transfer processes.