Multiporphyrin Arrays on Cyclotriphosphazene Scaffolds

We report the synthesis of first examples of hexaporphyrin and dodecaporphyrin assemblies on cyclotriphosphazene scaffold by adopting two different approaches based on Ru-pyridyl “N” coordination in decent yields. The multiporphyrin assemblies were confirmed by ³¹P, ¹³C, ¹H, ¹H–¹H COSY, and NOESY NMR spectroscopic studies. The absorption studies showed 2-fold intensity enhancement with negligible changes in peak maxima compared to porphyrin monomers. The redox potentials of multiporphyrin assemblies showed the redox features of the constituted porphyrin monomers and supported weak interactions among the porphyrin units in noncovalent hexaporphyrin and dodecaporphyrin arrays.