Spectral Analysis Of Porphyrins And Porphyrin-montmorillonite Complexs And Their Interaction With O₂and CO

Porphyrins, which composed of the "tetra-pyrrole" ring with18Ï€ electrons, exist widely in the bodys of natural animals and plants, such as chlorophyll, hemin, cytochrome and so on. Since their many special properties, for instance, conjugated structure, complicated three-dimensional configuration and various substituents, the porphyrins have highly research significance and application value in the fields of bionic catalysis, simulation of oxygen-carrying, photoelectric conversion, drug chemistry and analytical chemistry. Nevertheless, molecules of porphyrins tend to aggregate in aqueous solutions by hydrogen bond, coordination, electrostatic interactions, accumulation effect and other ways so that the physical and chemical properties of porphyrins are influenced.The significant feature of montmorillonite, which is a kind of natural and swelling layer silicate mineral, is2:1-type crystal structure composing of two silicon-oxygen tetrahedrons and an aluminum-oxygen octahedron. Moreover, there are exchangeable cationic ions between montmorillonite layers. Therefore, montmorillonite can combine with organic molecules and then improve their condition, stability, solubility and other physical and chemical properties remarkably.With reference of previous literatures, TA4C which is the derivative of tetra-(4-aminophenyl)porphyrin modified by succinic anhydride, protoporphyrinIX and zinc protoporphyrinâ…¨ were synthesized and characterized using the ultraviolet-visible absorption spectrum, infrared absorption spectrum, nuclear magnetic resonance spectroscopy and other analysis methods. Then, the porphyrins were loaded on the layer structure of montmorillonite. The effect of montmorillonite on porphyrins aggregates was studied using the ultraviolet-visible absorption spectrum and fluorescence spectrum. Sequently, properties of porphyrins and porphyrin-montmorillonite complexes bonding to oxygen and carbon monoxide were researched. Finally, the application of porphyrins in the fields of biochemistry and medicine was explored.The results showed that:(1) montmorillonite can interact with TA4C and protoporphyrinIX, then suppressed the aggregation of porphyrins effectively. But the interaction between montmorillonite and zinc protoporphyrinIX was not distinct.(2) Oxygen can influence a little the fluorescence property of TA4C. But oxygen molecules can coordinate with protoporphyrinIX and zinc protoporphyrinIX and change their fluorescence spectra.(3) Carbon monoxide can quench the fluorescent spectra of TA4C molecules and the complexes of TA4C and montmorillonite. Meanwhile, carbon monoxide can lead to blue shift of the fluorescence emission peaks of protoporphyrin â…¨ and red shift of the fluorescent spectra of the zinc protoporphyrin â…¨complexes.