Electronic structure of novel phthalocyanine analogues containing the 1,2,4-triazole unit

The molecular structure and electronic properties of the phthalocyanine analogues metal-free triazolophthalocyanine (H2TPc) and metal-free triazolohemiporphyrazine (H2THp) are investigated using semiempirical and ab initio methods. The introduction of the triazole moiety in the phthalocyanine skeleton induces: i) an increase of the oxidation potential, ii) a decrease of the reduction potential, and iii) an opening of the splitting between the near degenerate Qx and Qy absorption bands.