Design and synthesis of porphyrins bearing rigid hydrogen bonding motifs: highly versatile building blocks for self-assembly of polymers and discrete arrays.

Two aldehydes, 2,6-diacetamido-4-formylpyridine (7) and 1-butyl-6-formyluracil (11), are used to synthesize five pyridyl and four uracyl meso-subsituted porphyrins. With these complementary porphyrin building blocks, it is possible to build various types of multi-porphyrin supramolecules with different spatial relationships in predefined geometries. The formation and properties of self-complementary dimers and a closed tetrameric square are presented as a basis of comparison to the latter system in the solid state. An X-ray structure of 5,10-bis(4-tert-butylphenyl)-15,20-bis(3,5-diacetamido-4-pyridyl)porphyrin confirms its molecular structure and reveals a hydrogen-bonded supramolecular organization mediated by water molecules.