Rings-and-String Approach to the Construction of porphyrin Arrays by Transition-Metal-Directed Threading

摘要

Multiporphyrins are particularly attractive for studying photoinduced long-range electron transfer and modeling of the photosynthetic reaction center. The vast majority of the systems described until now dispose porphyrins in a desired spacial arrangement by linking them covalently. Clearly, a modular approach to noncovalent assembly is appealing, since it should reduce synthetic work and allow the rapid construction of relatively elaborate multicomponent structures from a collection of simple modules. Recent examples of noncovalently linked systems incorporating two or more porphyrins include those based on the formation of hydrogen bonds, as well as coordination of porphyrin-carrying ligands to metal ions. To the best of our knowledge, the only system containing two different porphyrin nuclei reported in this latter group is constructed around a substitutionally inert ruthenium(II) core complex.