Abstract
The shift of the Q-band of sodium zinc(II)-2,9,16,23-phthalocyanine tetracarboxylate (ZnPc(COONa)(4)) to about 800 nm is attributed to the influence of the electron-donating property of the carboxylate groups substituted in the beta-position. ZnPc(COONa)(4) which was found to have a symmetry of D (2h) characterized by a splitting of the Q transition. This splitting was interpreted by the formation of dianionic symmetric ZnPc(COONa)(4) resulting from the dissociation of the pyrrole protons as well as the possibility of Na+ dissolution of ZnPc(COONa)(4) in the aqueous solution of NaOH.