The Calculation Of Charge Distribution In Iron Porphyrins

The calculation of charge distribution in iron porphyrins Iron porphyrins play an important role in organism. People are familiar with iron porphyrins including hemoglobin of transferring oxygen, cytochrome C and cytochrom P-450. Since molecular charge distribution is closely related to molecular properties, it is important to calculate charge distribution of iron porphyrin compound. Conventional ab initio methods are hard to apply to the large molecular systems, so developing an accurate and economic method to probe the relationship between structures and properties of large molecules is a promising research area in nowadays theoretical chemistry. We have proposed an atom-bond electronegativity equalization model(ABEEM) on the basis of density functional theory and electronegativity equalization principle. Using separated program, through regression and least-squares optimization, the parameters of atoms and bonds in molecules are determined. By these parameters, the charge distributions and the energy of iron porphyrins are calculated. The time of calculation is short and the results are good.