Synthesis, structure and physicochemical properties of a saddle-distorted porphyrin with a peripheral carboxyl group

A saddle-distorted porphyrin bearing a carboxyl group as a hydrogen-bonding site on a meso-phenyl group was synthesized and characterized. A supramolecular structure with intermolecular hydrogen bonding was revealed by X-ray diffraction analysis. The effects of the peripheral carboxyl group on the physicochemical properties of the porphyrin as well as on self-assembly were investigated by spectroscopic measurements in solutions. The redox properties of the porphyrin and its Zn(II) complex were also studied by electrochemical measurements and their application to dye-sensitized solar cells was examined.