Structure of meso-tetraaryl-β-octahalogeno-porphyrins : a semi-empirical quantum mechanical investigation

Abstract

AM1 calculations have been performed on three series of porphyrins, namely β-octahalogenoporphyrins, meso-tetraphenylporphyrins and meso-tetraaryl-β-octahalogenoporphyrins and on their zinc complexes. In the case of meso-tetraphenylporphyrins and β-octahalogenoporphyrins, a planar structure of the tetrapyrrole ring is found to be the most stable one, as expected. On the contrary, the preferred conformation of meso-tetraphenyl-β-octabromo(chloro)porphyrins and their zinc complexes corresponds to a saddle shape structure