π-Electron delocalization and electronic transitions in oligomeric and polymeric phthalocyanine zinc(II) complexes. Part 1: Linear oligo- and one-dimensional polyphthalocyanines

Abstract

In this Part 1 of our two part study, 1D-linear oligomeric phthalocyanine zinc(II) with fully annulated (fused) phthalocyanine macrocycles are described. By semi-empirical and DFT computational methods the UV-vis and near infrared spectra, including energy gaps, are thoroughly evaluated. The long-wavelength Q band of the oligophthalocyanines is compared with the long wavelength absorption band of analogous oligoacenes consisting of annulated benzene rings. In addition, graphene nanoribbons are considered. The aromaticity is especially interesting when considering Clar’s rule. Therefore it is the aim to get information about the extent of [Formula: see text]-electron delocalization in linear or semi-linear systems. Finally, the results of linear oligophthalocyanines are extrapolated to estimate the energy gap of 1D linear polyphthalocyanine by DFT, and the result is compared to the DFT calculation of the periodic structure with a plane-wave basis set. Part 2 will describe non-linear oligo- and two-dimensional polyphthalocyanines.