物理化学学报 >> 2010, Vol. 26 >> Issue (10): 2763-2771.doi: 10.3866/PKU.WHXB20101005

量子化学及计算化学 上一篇    下一篇

双螺旋金属(II) 卟啉的结构、电子光谱及其反应活性

钟爱国1, 黄凌1, 李佰林1, 蒋华江1, 刘述斌2   

  1. 1. 浙江台州学院医药化工系,浙江临海317000;
    2. Research Computing Center, University of North Carolina,Chapel Hill, North Carolina 27599-3420, USA
  • 收稿日期:2010-06-10 修回日期:2010-07-16 发布日期:2010-09-27
  • 通讯作者: 钟爱国, 刘述斌 E-mail:longlinyun@tzc.edu.cn;shubin@email.unc.edu

Structure, Spectroscopy and Reactivity Properties of Helically Chiral Metal(II)-Bisdipyrrin Complexes

ZHONG Ai-Guo1, HUANG Ling1, LI Bai-Ling1, JIANG Hua-Jiang1, LIU Shu-Bin2   

  1. 1. Department of Chemistry, Taizhou College, Linhai 317000, Zhejiang Province, P. R. China;
    2. Research Computing Center,University of North Carolina, Chapel Hill, North Carolina 27599-3420, USA
  • Received:2010-06-10 Revised:2010-07-16 Published:2010-09-27
  • Contact: ZHONG Ai-Guo, LIU Shu-Bin E-mail:longlinyun@tzc.edu.cn;shubin@email.unc.edu

摘要:

由两个拓展的卟吩环键合不同的金属离子形成的卟啉结分子是生命体系中DNA 双螺旋分子最简单的金属扭结模型物, 在仿酶催化反应等方面存在广阔的应用空间. 本文选取8 个典型的二价金属离子(M(II), M=Ca, Mg, Mn, Zn, Cu, Ni, Fe, Co) 与拓展卟吩结分子(1H) 形成的单金属卟啉结配合物(1M) 和双金属卟啉结配合物(2M), 用密度泛函理论(DFT) 、含时DFT 和概念DFT 等工具, 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. 模拟结果显示1M、2M 的结构、光谱及其反应性质不同于其前体1H: 形成1M 和2M 金属配合物分子后, 将有较高的亲电指数和较低的化学硬度以及呈现紫外吸收峰位移; 形成2M 双金属配合物后, 绝大多数金属离子形成的2 个四配位环境的对称性较1M 体系有了提高, 同时DFT 反应指数也有显著的增强. 但2M 体系的调变能力也不尽相同: 主簇金属和含饱和电子结构离子较弱, 过渡金属离子强些, 二元描述符(dual descriptor) 结果支持了以上结论. 在这些典型的二价金属配合物中, 金属原子M 和配体原子N 之间的自然电荷分布, 金属原子M 和配体原子N 之间的二级微扰相互作用能, 配合物的前线轨道能级与其硬度指数、键的离解能与自然电荷等方面, 存在着一系列定量的相关关系, 相关系数(R2)在0.858-0.986 之间. 本研究对理解含有金属离子的重要生物物质在结构和反应性能上的差别将提供有益启示.

关键词: 电子光谱, 拓展卟吩, 金属卟啉, 螺旋分子, 密度泛函理论

Abstract:

The tetradentate coordination of bisdipyrrin ligands from cyclooctapyrroles with single and double metal cation metalations generates helical chirality and brings about recent research interests in supremolecular chemistry. In this study, eight divalent metal cations (M(II), M=Ca, Mg, Mn, Zn, Cu, Ni, Fe, Co) in the formation of the singly metalated complexes (1M) and binuclear metal complexes (2M) are systematically investigated to appreciate their structure, spectroscopy, and reactivity properties by using density functional theory (DFT), time-dependent DFT, and conceptual DFT approaches. Their bonding properties are analyzed by the natural bond orbital (NBO) analysis. The simulation results revealed that structure, spectroscopy, and reactivity features of the 1M and 2M complexes are markedly different from their precursor bisdipyrrin (1H) with a larger electrophilicity index, smaller chemical hardness, and distinctive dual descriptor. UV-Vis spectra show diminished peaks with red shifts due to metalation.A few linear structure-reactivity relationships stemmed from these structure and reactivity properties have been obtained with the correlation coefficient (R2) between 0.858 and 0.986. The results can provide in-depth insights for these complexes from structure and reactivity viewpoints.

Key words: Electronic spectrum, Bisdipyrrin, Metalloporphyrin, Helix molecular, Density functional theory

MSC2000: 

  • O641