POLYPORPHYRIN THIN-FILMS FROM THE INTERFACIAL POLYMERIZATION OF MERCAPTOPORPHYRINS

Free-standing ultrathin films of a porphyrin homopolymer have been syn thesized by interfacial polymerization of a mercaptoporphyrin. Couplin g of 10,15,20-tetrakis(alpha-mercapto-p-tolyl)porphyrin at the water/c hloroform interface by copper acetate yields continuous, flexible film s after drying with supercritical CO2. These films are amorphous and r etain many characteristics of the monomeric porphyrin, such as the pro perty that they may be metalated. Spectroscopic evidence suggests effi cient cross-linking of thiols through disulfide coupling occurs in the se polyporphyrins to form a network. Polymerization is accompanied by the introduction of carbonyl functionality, probably the transformatio n of residual thiols to thioacetate by metal-mediated reaction with ex cess acetate ion. As an example of the catalytic properties of these p olymers, they are shown to promote photooxidation of thietane to the c orresponding sulfoxide by sensitizing singlet oxygen production.