Synthesis Of Axially Substituted Indium Phthalocyanine And Its Nonlinear Optical Properties

Phthalocyanines（Pcs）are a series of aromatic macrocycles based on an extensive delocalized 18-πelectron system,which show excellent third-order nonlinear optical properties and have a variety of applications as optical limiting,optical data storage and optical switching materials.Efforts have been made to synthesis large conjugated system and soluble phthalocyanine complexes.However,aggregation of phthalocyanines in solutions caused by large conjugated system may weaken nonlinear optical effect,which affected the applications.Alkyl and alkoxy as peripheral substituents and axial ligands will play major roles in enlarging the distance among the phthalocyanine molecules and improving the solubility.A series of n-pentyloxy and iso-pentyloxy peripheral substituted indium and gallium phthalocyanines with different alkyl axial ligands were synthesized,includingα-（C_n）MPc（OR）₄,α-（C_n）MPc（OR’）₄ andβ-（C_n）MPc（OR）₄,where OR stands for n-pentyloxy,OR’stands for iso-pentyloxy,M stands for central metal and C_n stands for alkyl axial ligands with n carbon atoms.The phthalocyanine samples were characterized by UV-Vis spectral,FT-IR and MOLDI-TOF mass spectra.Among them,18 new complexes haven’t been reported until now.The third-order nonlinear optical properties were investigated using Z-scan technique,by which the nonlinear absorption coefficient,third-order nonlinear optical susceptibility and second-order nonlinear superpolarizability were obtained.Excited state lifetimes and quantum yields were acquird by fluorescence spectral and transient absorption spectral in order to investigate the nonlinear optical mechanism.The nonlinear optical properties were attributed to triplet reverse saturable absorption.The relationship between the molecular structure of complexes and nonlinear optical properties of complexes were explored,and the effect of the central metals,peripheral substituents and axial ligands on the third-order nonlinear optical properties was discussed.Axial indium phthalocyanine complexes showed stronger triplet absorption effect,resulting in better third-order nonlinear optical properties.