Synthesis And Character Studies On Porphyrins As Photosensitizers

Porphyrins, an important kind of life-substance, have been widely used in manyfields because of its special structure. Photodynamic Therapy(PDT) andphotosensitivizers(mostly of porphyrins) are active and hot topics. PDT is apromising new treatment modality for several diseases, most notably cancer. In PDT,light,O₂,and a photosensitizing drug are combined to produce a selective therapeuticeffect. Moreover, photosensitivizers have a important effect. Although thousandskinds of porphyrins have been studied to use as photosensitivizers , clinical PDTdrug for cancer ,is still photofrin developed in 1960s in abroad. Because the mostcommonly used porphyrin photosensitizers are far from ideal with respect to PDT,finding a suitable photosensitizer is crucial in improving the efficacy of PDT. Lately,There have been active research on new photosensitizer candidates, the purpose is totrying to sort out those photosensitizers that are advantageous for PDT.Herein we shall place emphasis on those photosensitizers that can easily be preparedstarting from the abundantly occurring natural precursors, protoheme andchlorophylls. Such emphasis is justified by economical and environment.As these reasons, we do such research on the followings .1. we synthesized protoporphyrin dimethyl ester and its complexes. It is important substances used for photosensitizers by means of semi-synthesis.2. we also synthesized meso-tetra methoxyl benzyl-benzoporphyrin Znic complexes.they are a kind of promosing photosensitizers.3. try to combine porphyrins with anti-cancer drug such as 5-fluorouracil.4. These complexes have been characterized by Elemental analyses, Uv-vis, IR spectra, NMR and Molar Conductance. The structures are proposed in which our idea are true.5. The compounds we synthesized have been studied by means of cyclic voltammetry, surface photovoltage and luminescence.I. Syntheses of the complexes:Structures of the compounds are follows:ea) Hemin b)protoporphyrin dimethylester c) protoporphyrin acid d) complexes ofprotoporphyrin dimethylester e) meso-tetramethoxylbenzyltetrabenzoporphyrin ZinccomplexII. Seperation and purfication of the compounds.The crude product was seperated by using Al2O3 column chromatograpy and thinlayer chromatograpy with suitable solution. Finally, we attained purified compounds.III.The characteristics of porphyrinsThese complexes have been characterized by Elemental analyses, Uv-vis, IR spectra,NMR and Molar Conductance. The structures are proposed in which our idea aretrue.IV. The cyclic voltammetryThe oxidation and reduction properties of the compounds were researched by thecyclic voltammetry, the oxidation –reduction potentialswere obtained. In 0.1 M(TBAP) DMF within the accessible potentialwindow of the solvent (scan rate = 100mv/s).V. Surface photo-voltage spectroscopy(SPS)We investigated the photo-generated charge behavior of VII...