Electronic Structures of Asymmetrically Substituted Phthalocyanines and Their Second Non‐linear Optical Properties

Quantum‐chemical AM1 calculations were performed to study the geometries, the electronic structures and the second nonlinear optical properties of phthalocyanine and some asymmetrically substituted phthalocyanines, which include tert‐butyl, amino, dimethylamino, nitro, fluoro, chloro, bromo, iodo and nitrile substituents. The relationships of the second nonlinear optical coefficients β with dipole moment μ, and β with the energy‐gap differences of frontier orbitals ΔE_DA were discussed. Two relationships are regular and all ΔE_DA ‐ μ show very good linear relationship.