The relationship of structure and optical properties of haloporphyrins: A new way to synthesize porphyrin chromophores and the investigation of their optical properties

A new synthetic method of octabromoporphyrin compounds has been created to simplify the conventional multi-step synthesis and purification to a one step reaction. A series of new meso-substituted β-bromoporphyrins, including tetraphenyloctabromoporphyrin (OBTPP), tetra-9-ethyl-carbazoleoctabromoporphyrin (TCarbOBP), tetra-2-thienyloctabromoporphyrin (T2-thioOBP), tetra-3-thienyloctabromoporphyrin (T3-thioOBP), tetra-5-bromo-2-thienyloctabromoporphyrin (5BrT2-thioOBP) and relative Zn porphyrins, have been prepared by this method. In this paper we discuss the synthesis of these compounds and their optical behaviors, especially the effects of the different meso-substituents on the photophysical properties. In order to investigate the different optical properties of porphyrins with β-bromo-substitution and without β-bromo-substitution, corresponding non-brominated meso-substituted porphyrins have also been synthesized and studied.