Eco-friendly and Effective Tetraphenylporpyrin Metalation Utilizing Ionic Liquids

Abstract

Metalation of porphyrins is carried out in the solvents considering the solubility of metal salts and free-base porphyrins. However, the methods using these solvents which have excellent dissolving ability also put at disadvantages such as decreasing reaction rates and yields, and high boiling point of the solvents. In this work, we investigated the Copper(II) metalation of TPP utilizing ionic liquids. The method using [C₈mim][Br] provided Cu^IITPP more effectively with lower amount of solvent than that of using DMSO. A series of studies using multiplicate imidazolium ionic liquids with various structures revealed that the [C₈mim][Br] is the most suitable ionic liquids for the Copper(II) metalation of TPP.