Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (04): 837-845.doi: 10.3866/PKU.WHXB20110323

• THEORETICAL AND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

Structure, Spectroscopy and Reactivity of H2S Bonding to Metal(II) Porphyrins

ZHONG Ai-Guo, HUANG Ling, JIANG Hua-Jiang   

  1. Department of Chemistry, Taizhou College, Linhai 317000, Zhejiang Province, P. R. China
  • Received:2010-10-29 Revised:2010-12-02 Published:2011-03-29
  • Contact: ZHONG Ai-Guo E-mail:zhongaiguo@tzc.edu.cn
  • Supported by:

    The porject was supported by the Natural Science Foundation of Zhejiang Province, China (Y4110348).

Abstract:

We investigated eight divalent metal cations M(II) (M=Ca, Mg, Mn, Zn, Cu, Ni, Fe, Co) for the formation of singly H2S-bonded metalated porphyrin-imidazole complexes (L-MP) and H2S bi-bonding of these metalated porphyrin complexes (L-MP*-L, L=H2S, P=porphyrin-imidazole, P*=porphyrin). We investigated their structures, spectroscopic and reactivity properties using density functional theory (DFT), time dependent (TD) DFT, and conceptual DFT approaches using global and local descriptors. Their bonding properties were also analyzed by natural bond orbital (NBO) analysis and by the frontier-electron theory of chemical reactivities. The calculated results reveal that the structures, spectra and reactivities of the L-MP and L-MP*-L complexes are very different from those of their precursor MP. Mg2+ can form stable complexes with porphyrin-imidazole while Ca2+ can not. The ligand L has little influence on the structure of the porphyrin-imidazole. L-MP is more reactive during electrophilic and nucleophilic reactions. UV-Vis spectra showed shifted peaks because of metalation. The iron complex differs from the other metal ion complexes in bonding and reactivity properties such as charge distribution, stability, and nucleophilicity. The transition from the high-spin (S=3) five-coordinate FeP to the lower-spin (S=1) six-coordinate L-FeP leads to a change in the Fukui index (fFe+) of the iron porphyrin. A few quantitative linear relationships were found for the bonding interactions, the charge distributions, and the DFT chemical reactivity indices. In addition, we note that the spin polarization Fukin function plays an important role in metal specificity and reactivity. These results provide in-depth insights into the vascular disorder from endogenous H2S bonded with metal porphyrin complexes.

Key words: Density functional theory, Conceptual density functional theory, Gasotransmitter, Metal-porphin complex

MSC2000: 

  • O641