Solvatochromic Shift of Phthalocyanine Q-band Governed by a Single Solvent Parameter

Position of the main optical absorption band (Q-band) in electronic spectra of some trans-[M(Pc)L2]^k (Pc = substituted or unsubstituted phthalocyaninate, M = Co(III), L = CN-, k = -1; M = Sn(IV), L = Cl-, k = 0; M = Sb(V), L = Cl-, k = +1) complexes depends only on the refractive index of the solvents, indicating that interaction of the transition dipole moment with induced dipole moment generated in the surrounding solvent molecules is predominant.