Porphyrin Synthesis in Surfactant Solution: Multicomponent Assembly in Micelles

A synthesis of meso-substituted porphyrins in anionic sodium dodecyl sulfate micelles has been developed. Polar, functionalized aromatic aldehydes condense reversibly with pyrrole in the micellar phase. Oxidation of the porphyrinogen then provides functionalized porphyrins in yields of 10-48%. Hydrophobic aldehydes condense irreversibly to give low yields at practical substrate concentrations. Synthesis in D(2)O solution results in per-beta-deuterated porphyrins. A two-phase model is used to rationalize the dependence of porphyrin yield on reactant and surfactant concentration. Micelles are viewed as potential wells which promote porphyrinogen assembly by binding products more tightly than reactants.