Synthesis And Structure Characterization Of New Porphyrin Derivatives Based On Palladium-Catalyzed Coupling Reaction

Since the porphyrin and metalloporphyrin compounds have unique chemical structures, special biological functions and photoelectric properties, they have been widely studied and applied in synthetic chemistry, biochemistry, pharmaceutical chemistry, analytical chemistry, materials science and many other fields in recent years. As a result, this area is growing rapidly and many new methods of synthesizing porphyrin compounds with various substituent have been developed. Particularly the synthesis of 5,10,15,20-tetraphenylporphyrin derivatives are most studied. Palladium-catalyzed Stille coupling reaction, Sonogashira coupling reaction are the most commonly used carbon-carbon formation reactions in modern organic synthesis.In order to explore the new way of synthesizing of tetraphenylporphyrin derivati- ves, we prepared compounds [5-(4-bromophenyl)-10,15,20-triphenylporphyrin]zinc by [2+2] method. And we tried to couple [5-(4-bromophenyl)-10,15,20-triphenylporphyri- n]zinc with substituted benzene ring by using Stille coupling reaction, Sonogashira Coupling reaction to give (5-biphenyl-10,15,20-triphenylporphyrin)Zinc derivatives. The Stille coupling reaction gave the best result, using this method we synthesized some new porphyrin compounds [5-{4'-[N-(tert-butoxycarbonyl)amino]-biphenyl-4- yl}-10,15,20-triphenylporphinato]zinc, 5-(4'-amino-biphenyl-4-yl)-10,15,20-triphenyl- porphyrin, [5-(4'-amino-biphenyl-4-yl)-10,15,20-triphenylporphinato]zinc, [5-(4'-met- hylthio-biphenyl-4-yl)-10,15,20-triphenylporphinato]zinc. The structures of all the products were characterized with UV, NMR, MS, IR.We also studied the fluorescence properties and the quantum yield of the new porphyrin compounds. Comparing with [5-(4-bromophenyl)-10,15,20-triphenylporphy- rin]zinc, The absorption peak of the Soret band and Q band of the new porphyrin compounds has a red shift and the new compounds have better quantum yield. It is probably due to increasing conjugate degree by introducing another pleny ring on 5 position of tetraphenylporphyrin.We also studied the electrochemical properties of some new porphyrin compounds by cyclic voltammetry. We found that each oxidation and reduction process of each compound have two electrons gains and losses respectively, and the electrode reactions were [TPPZn]/[TPPZn]++e-;[TPPZn]+/[TPPZn]2++e-. Comparing oxidation-reduction potential of these compounds, we found that the higher conjugate degree of porphyrin compounds, the more difficult to be oxidized.The electron sufficient metalloporphyrin is easier to be oxidized comparing with porphyrin.