DFT study of alkynyl porphyrin dimers and brominated tetraphenyl porphyrins

摘要

Geometry optimizations and electronic structure calculations using Density Functional Theory (DFT) are reported for tetra-acetylene porphyrins (TAP), their dimers, and octabromotetraphenyl porphyrins (OBP). The acetylene group group contributes to the pi -electron conjugation along the porphyrin ring for the HOMO and LUMO, and reduces significantly and HOMO-LUMO gap. The gap is further reduced in dimers. The planar geometry of the TAP dimer has a lower energy than the non-planar one. The geometry of H_2OBP is found to be non-planar, and the distortion of porphyrin ring is shown to be closely related to the HOMO-LUMO gap.