Synthesis and Characterization of Aryl-substituted 5,15-Diazaporphyrins

Abstract

Porphyrins and phthalocyanines are very useful for a variety of photochemical and photophysical applications. In order to utilize these chromophores, it is necessary to control their properties favorably. For this purpose, a lot of researchers have synthesized and investigated various porphyrin analogues, such as meso-aza-substituted porphyrins. However, there are few studies on synthesis and characterization of 5,15-diazaporphyrins and their aryl-substituted derivatives. Now, we have succeeded in synthesizing a variety of meso- and beta-aryl-5,15-diazaporphyrins, and characterized their properties. Hexaaryl substituted 5,15-diazaporphyrins were obtained in good yield in spite of large steric hindrance because of their high solubility. In the absorption spectra, hexaaryl substituted 5,15-diazaporphyrins show large bathochromic shifts in both Soret and Q bands (about 27-35nm bathochromic shift relative to all-alkyl type 5,15-diazaporphyrin). We report the synthesis of a series of meso- and/or beta-aryl-5,15-diazaporphyrins, and discuss the controlling their photochemical properties.