Hexakis (pyridyl-functionalised porphyrinato)benzene as a building block for the construction of multi-chromophoric arrays

• Published in: Tetrahedron letters 2002-12, Vol.43 (51), p.9351-9355
• Main Authors: Lensen, Marga C., Castriciano, Mariangela, Coumans, Ruud G.E., Foekema, Jantien, Rowan, Alan E., Scolaro, Luigi Monsù, Nolte, Roeland J.M.
• Format: Article
• Language: English
• Subjects: metal-directed self-assembly; nanostructures; porphyrin arrays; supramolecular chemistry
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/S0040-4039(02)02342-0

A new hexakis porphyrinato benzene compound has been synthesised and studied by different spectroscopic techniques. It consists of 6 porphyrin moieties which are covalently attached to one central benzene core. Each porphyrin contains 3 pyridyl functions, making a total of 18 potential coordination sites. The structure is a multi-porphyrin array in its own right but can be extended further by means of metal-directed self-assembly. This was demonstrated with the help of a platinum diimine complex substituted with two dodecyl-tails. The pyridine-functionalised hexa-porphyrin was found to bind only 6 instead of the expected 18 platinum complexes, which is ascribed to steric hindrance. Electron microscopy studies reveal that both the pyridine-functionalised hexaporphyrin and its metal-coordination product form well-defined ring structures of micrometer size on solid supports. A hexakis porphyrinato benzene-functionalised with 18 pyridine groups binds only six platinum diimine complexes due to its propeller-like structure and self-assembles to form ring-shaped architectures on a carbon substrate.