Abstract: Thin polymeric porphyrin films have been prepared by interfacial polymerization of a pair of reactive comonomers, one or both of which are derivatized porphyrins. Typical monomer pairs are tetra(p-hydroxyphenyl)porphyrin (THPP) in aqueous base with tetra(p- chlorocarbonylphenyl)porphyrin (TCCPP) in chloroform or dichloromethane, tetra(p- aminophenyl)porphyrin (TAPP) in DMSO with TCCPP in ethyl acetate, and various aliphatic diamines in water with TCCPP in chloroform. Typical film thicknesses are in the range 0.01 - 10 $mu@m. The films display a unique chemical asymmetry, in the sense that opposite surfaces of the films show distinctive differences in the concentration and type of functional groups that are present. When placed between semitransparent electrodes and irradiated with either steady-state broad-band light or a pulsed laser, these films develop directional photopotentials, whereby the film surface that was prepared in contact with the TCCPP solution (the acid surface) develops a more negative potential than the opposite (amine or hydroxyl) surface. We consider the directional photopotentials to be a manifestation of the chemical asymmetry of these interfacial films - that is, photoinduced charge separation involves electron transfer towards the acid surface of the film, which corresponds to the predicted trends of oxidation and reduction potentials of the various porphyrins within the polymer film. !
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