Electrosynthesis of novel π-extended benzofuran derivatives of porphyrincatecholes

Two new functionalized π-extended benzofuran catechol porphyrins and nanostructured Mn-porphyrins have been synthesized by a green one-pot method and structurally characterized by spectroscopic analysis. The electro-oxidation of 5,10,15,20-tetrakis(2,3-dihydroxyphenyl) porphyrins(1a-b) with four catechol units in the presence of 3-hydroxy-1H-phenalene-1-one (3) as bidentate nucleophile has been done and benzofuran rings have formed by the intermolecular and intramolecular Michel addition reactions. Coulometry and voltammetry results allowed us to propose four independent ECEC mechanisms for the electrochemical oxidation pathway. Functionalization of the porphyrins affected their photophysical properties such as the efficiency of the fluorescence that would support the energy transfer between the porphyrin core and the substituted subunits.

► Two new functionalized π-extended benzofuran catechol porphyrins have been synthesized.
► Electrosynthesis produces green, selective method of functionalization of porphyrins.
► Energy transfer between the porphyrin core and the substituted subunits took place.
► Benzofuran rings have formed by the intermolecular and intramolecular Michel addition reactions.
► Porphyrin nano-particles were synthesized directly on electrode.