Synthesis Of Series Of Metalloporphyrins And The Study Of Its Spectroscopic Properties

Metalloporphyrins are widely existed in natural world. Since early chemists extracted it from natural plants, its unique structure and property have been attracting scientists generation after generation. As Paul Rothemund synthesized the simplest tetraphenyl porphyrin in the 1930’s, thousands of porphyrin compounds have been synthesized, studied and used in the fields of host and guest chemistry, self-assembly, material, and chiral catalytic.In this paper, eight amino acid tailed porphyrins are designed and synthesized, using p-HOTPP or o-HOTPP as the basic material with five chiral amino acid as the tailed group. Elementary analysis, 1H NMR, IR, UV-vis were used to characterize the zinc porphyrins.And then, the axial addition between chiral zinc porphyrins and nonchiral N ligands is studied. Chiral zinc porphyrins are chosen to be the host molecules, imidazole and N-methyl imidazole are chosen to be the guest molecules. As the solution of different concentration of guest molecules is titrated into the host, we detect the decrease in the fluorescence spectra of the coordination system, which demonstrates fluorescence quenching from the imidazole derivative to the chiral zinc porphyrin. In the further study of the mechanism of the fluorescence quenching between the host and guest, quantative analysis is performed by the Stern-Volmer equation. Using the guest concentration as the x and ratio of fluorescence intensity from the host molecule to the coordination system as the y, we can get linear equation. Then the fluorescence quenching constant Ksv and quenching rate constant Kq is deduced. Influenced by the molecular structure, the quenching rate constant Kq of ortho-replaced zinc porphyrin is much lower than that of para-replaced zinc porphyrins.