Theoretical Study Of The Structure And Properties Of Phthalocyanine Compounds

Phthalocyacine(Pc) is a kind of importangt dyes and/or pigments, which are also widely used in the fileds such as high-density optical data storage and non-linear optics (NLO). In this thesis, a systematic theoretical investigation has been performed to study the structures and properties of Pcs using the quantum chemical methods i.e., density functional theory (DFT), ZINDO, and Coupled-Perturbation Hartree -Fock (CPHF).First, calculations were carried out on a series of Pcs using several different theoretical methods. The calculated results of various methods are compared and the reliability of the results is tested. The geometries and frequencies obtained at the B3LYP/3-21G and B3LYP/LanL2DZ levels are quite good, and are comparable to the B3LYP/6-311G** results. Moreover, the CPU time and computer resource desired by the B3LYP/3-21G and B3LYP/LanL2D calculations are much less than the B3LYP/6-311G** and therefore can be used to study relatively larger systems such as Pcs. They were chosen in this study to calculate the molecular geometries, electronic structures, and IR spectra of a series of Pcs having different centers or/and different substituents on the benzene rings. CPHF and ZINDO are the most popular methods to study the non-linear optical and excited state properties, respectively. They were used to calculate the NLO polarizalibility, excited state and UV/Vis spectra of Pcs.The thesis mainly have studied the effects of the property and position of substituents as well as the different metal centers on the molecular geometries, electronic structures, IR and UV spectra, thermodynamics, and non-linear optical properties. Certain relationships were found between the dipole moment u, the energy difference of frontier orbitals AE, the charge transfer AQ ,and the non-linear optical coefficient β_vec.