A comparison of structural and electronic characteristics among subphthalocyanine and phthalocyanine complexes

Molecular orbital calculations are used to analyze factors that lead to structural differences among a series of four subphthalocyanine and two phthalocyanine complexes. The effects of changing the central atom from boron to aluminum and from carbon to silicon are elucidated for the corresponding subphthalocyanine complexes. In addition, carbon and silicon phthalocyanine complexes are compared. Results of the calculations suggest that the complexes assume a concave or planar conformation depending on the relative size of the central atom and the cavity, irrespective of electronic factors. The nature of the bonding between the central atom and the subphthalocyanine macrocycle is also investigated.