物理化学学报 >> 2011, Vol. 27 >> Issue (04): 837-845.doi: 10.3866/PKU.WHXB20110323

理论与计算化学 上一篇    下一篇

H2S键合金属(II)咪唑卟啉配合物的结构、光谱和反应活性

钟爱国, 黄凌, 蒋华江   

  1. 台州学院医药化工学院, 浙江 临海 317000
  • 收稿日期:2010-10-29 修回日期:2010-12-02 发布日期:2011-03-29
  • 通讯作者: 钟爱国 E-mail:zhongaiguo@tzc.edu.cn
  • 基金资助:

    浙江省自然科学基金(Y4110348)资助项目

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).

摘要:

选取8个典型的二价金属咪唑卟啉MP(M=Ca, Mg, Zn, Cu, Ni, Fe, Co, Mn; P代表咪唑卟啉)与H2S(L)形成轴向金属配合物(L-MP; L-MP*-L, P*代表卟啉), 应用轨道和自旋概念密度泛函工具, 在优化构型的基础上, 通过自然键轨道(NBO)方法和前线轨道能级研究了它们的分子结构、光谱性质和反应活性. 模拟结果揭示L-MP和L-MP*-L结构、光谱及其反应活性不同于其前体MP. MP排斥钙而选择镁; L对MP的结构影响较少, 与咪唑铁卟啉(FeP)能形成最稳定的单轴配合物(L-FeP), 其电子吸收光谱较前体FeP有显著的变化; 铁的亲核Fukui轨道指数值(fFe+)大于其他原子的Fukui指数, 且发生符号改变. 铁体系的自旋极化Fukui密度图也支持以上结论. 在这些典型的赤道键合配合物中, 金属M与N(S)原子之间的二级微扰相互作用能、自然电荷以及概念密度泛函指数等存在一系列线性关系. 以上结果可为理解内源性H2S与血管性物质的相互作用机理提供启示.

关键词: 密度泛函理论, 概念DFT, 信号分子, 金属卟啉配合物

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