The renaissance in optical spectroscopy of phthalocyanines and other tetraazaporphyrins

Abstract

Spectral properties of metallophthalocyanines and other tetraazaporphyrins are governed mainly by the Q band which originates from the π-π* transitions within the ring. The position and intensity of the Q band is important in tailoring new phthalocyanine derivatives for particular applications. Aggregation, the nature of the central metal, π conjugation, symmetry of the molecules, and axial, peripheral or non-peripheral substitutions affect the spectra and hence the properties of the phthalocyanine molecule. This review gives a brief outline on how optical spectroscopy provides useful informations on molecular and electronic structures, chemistry and physics of phthalocyanines and other tetraazaporphyrins.