Synthesis of porphyrin cyclic oligomer based on quadruple hydrogen-bonding

Synthesis of a porphyrin cyclic oligomer based on ureidpyrimidinone, which forms a stable dimer via self-complementary quadruple hydrogen bonding, will be discussed. In our synthetic strategy, excess hydrogen-bonding unit namely, isocytosine was activated by carbonyldiimidazole to react with two amino groups of a porphyrin. This methodology is quite advantageous in terms of its efficiency and accessibility towards a supramolecular porphyrin cyclic oligomer. The concentration dependence of the ring-chain equilibrium in the supramolecular porphyrin oligomer was also investigated by diffusion ordered spectroscopy. Furthermore, results of the metathesis reaction to isolate the cyclic oligomer, will be also mentioned.