Evaluation of Ground and Excited State Dipole Moments of 2(3)-tetra(tert-butylphenoxy)phthalocyaninato Zinc(II) from Solvatochromic Data

Abstract

This article presents a semi-empirical determination of ground state dipole moment (g) and excited state dipole moment (e) of 2(3)-tetra(tertbutylphenoxy)phthalocyaninato zinc(II) (ZnTBPc) using the solvatochromic shift method, which is based on the Onsager's reaction field theory. A combined application of the Bakshiev's equation and the Kawski-Chamma-Viallet's equation was used to determine the ratio e/g while the use of the molecular-microscopic solvent polarity parameter yielded the term  (e-g). The dipole moment of ZnTBPc in its excited singlet state (e=4.46D) is more than twice as much as that in its ground state (g=2.14D). These values suggest that the higher charge separation is greater in the excited state of ZnTBPc than in its ground state.