Metal–ligand coordination in subphthalocyanines and phthalocyanines: DFT, AIM and ELF analyses

Abstract

A comparative study of subphthalocyanines and phthalocyanines was carried out using high-level quantum chemistry calculations. These calculations represent the highest computational level that has been employed in a systematic study of such oligopyrrolic macrocycles. The boron–phthalocyanine coordination mode is quite different from many other metal–phthalocyanine modes. A metal–ligand bond in a subphthalocyanine is shorter and stronger than that in a phthalocyanine. All metal–ligand bonds are polar bonds with both covalent and ionic natures. The thermodynamic data is consistent with the relative stability of subphthalocyanines and phthalocyanines that have been examined. Fukui functions suggest that the attack perpendicular to the carbon atoms adjacent to the meso nitrogen atoms is probably an initial step for the decomposition of a subphthalocyanine.