Density Functional Theory Study Of The Structure And Properties Of Sub-phthalocyanine Derivatives

Subphthalocyanines (SubPcs) are homologues of Phthalocyanines with large aromatic core and non-center symmetry cone-shaped structures, and have potential applications as optical materials for high-density optical data storage etc. In this thesis, a relatively systematic theoretical investigation has been peformed using the quantum chemical methods to study the structures and properties of a series of SubPcs.First, calculations have been carried out on eight SubPcs using ten different theoretical methods. The calculated results of various methods are compared and the reliability of the results is tested. It is found that the semiempirical MNDO and AMI methods, Hartree-Fock ab initio methods, and B3LYP/SpWG method are not suitable for calculating SubPcs. The geometries and frequencies obtained at the B3LYP/3-21G level are quite good, and the total energies are linearly correlated with the B3LYP/6-311G** results. Furthermore, the CPU time and computer resource desired by the B3LYP/3-21G calculations are much less than the B3LYP/6-311G** and therefore can be adopted to study relatively large systems. In a word, B3LYP/3-21G is a suitable theoretical method for studying SubPcs.Then, the molecular geometries, electronic structures, and spectra of 117 SubPcs having different center, different axial ligand, or different substituents on the benzene rings are studied employing the B3LYP/3-21G method. The calculated structures of all SubPcs with the center of boron (B), aluminum (Al) or beryllium (Be) are cone-shaped. The angles of the isoindole unit rotating around the axis through its alpha carbons are about 26° ~ 28° in the derivatives with the B center, and they are 40?and 34.8° respectively when the centers are Al and Be. Substitution has little effect on the magnitudes of