Density Functional Theory Study On Porphyrin Derivates

Porphyrins and metalloporphyrins have good optical and thermal stability, their absorption spectra lie in visible area. And they have many physical and chemical characters, so they are widely used in biochemistry, medical chemistry, analytical chemistry, actinic catalysing and meterial chemistry. In this paper, synthesis and application of porphyrins and metalloporphyrins were reviewed briefly.Despite of many experimental studies on porphyrin derivates about their syntheses and applications, theoretical investigations are much less. Therefore, it is imperative to study the structure-property relationship to explain experimental facts and to predict unknown information.In this paper, we applied dentisy functional theory(DFT) method to optimize a series ofporphyrin deritivates (meso-trtra[o-(3-sulfopropylamino)phenyl]porphyrin (TArP₁), meso-trtra[p-(3-sulfopropylamino)phenyl]porphyrin (TArP₂), meso-tetra(o- amino-phenyl)porphyrin (TNPP₁), meso-tetra(p-amino-phenyl)porphyrin (TNPP₂) and the Co(â…¡) complex with TNPP₁ [TNPP₁Co(â…¡)]. Their bond lengthes, bond angles, atomic charges, dipoles and frontior molecular orbitals were mainly studied and a lot of important information were obtained : there is a dihedral angle of about 69～76°between benzene ring and porphyrin ring, which indicated that they don't form a big conjugated system, and this can be obtained by bond length data ; the atomic charges are mainly in N atoms, and they are the active spot of these molecules ; dioples of TArP₁ and TArP₂ are biger than those of TNPP₁, TNPP₂, TNPP₁ Co(â…¡) and TArP₁ Co(â…¡), so TArP₁ and TArP₂ have better solubility in water ; UV spectra ofTArP₁, TArP₂, TNPP₁Co(â…¡) and TArP₁ Co(â…¡) can be calculated from frontior molecular orbitals of these molecules, and there is a blue shift in UV spectra of them compared with the experiment data.