物理化学学报 >> 2012, Vol. 28 >> Issue (02): 257-264.doi: 10.3866/PKU.WHXB201112091

热力学,动力学和结构化学 上一篇    下一篇

cis-[Ni(NCS)2tren]的镜面对称性破缺: 螯环的特殊手性构象

刘成勇, 颜建新, 林以玑, 李丹, 方雪明, 章慧   

  1. 厦门大学化学化工学院化学系, 固体表面物理化学国家重点实验室, 福建厦门 361005
  • 收稿日期:2011-09-28 修回日期:2011-12-01 发布日期:2012-01-11
  • 通讯作者: 章慧 E-mail:huizhang@xmu.edu.cn
  • 基金资助:

    国家自然科学基金(20773098, 20973136)资助项目

Mirror Symmetry Breaking of cis-[Ni(NCS)2tren]: Special Chiral Conformations of Chelate Rings

LIU Cheng-Yong, YAN Jian-Xin, LIN Yi-Ji, LI Dan, FANG Xue-Ming, ZHANG Hui   

  1. State Key Laboratory of Physical Chemistry of Solid Surface, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian Province, P. R. China
  • Received:2011-09-28 Revised:2011-12-01 Published:2012-01-11
  • Contact: ZHANG Hui E-mail:huizhang@xmu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20773098, 20973136).

摘要: 为了探究cis-[Ni(NCS)2tren] [tren: 三(2-氨基乙基)胺]的手性来源, 本文采用单晶X射线衍射、溶液紫外-可见-近红外(UV-Vis-NIR)光谱、固体紫外圆二色(CD)光谱和粉末X射线衍射(XRD)等对cis-[Ni(NCS)2tren]的一对手性晶体进行了表征. 研究结果表明: 该手性晶体由结晶过程中的镜面对称性破缺而形成; 三角架型配体tren 配位后的特殊手性构象(δδλ, λλδ)是cis-[Ni(NCS)2tren]的主要手性来源. 络合物固体紫外CD谱所呈现的Cotton 效应可能来自其螯环手性构象以及手性金属中心对NCS-配体的π-π*跃迁和荷移跃迁生色团的手性微扰. 对20批次合成产物进行固体CD检测的统计结果表明: 它们的对映体过量(ee)值在39%-100%之间.

关键词: 手性, 镜面对称性破缺, 螯环构象异构, 三(2-氨基乙基)胺, 固体CD光谱

Abstract: In order to explore the chiral origin of cis-[Ni(NCS)2tren] [tren: tris(2-aminoethyl) amine], a pair of chiral crystals of cis-[Ni(NCS)2tren] was characterized by X-ray single crystal structural analysis, solution UV-Vis-near infrared (NIR) spectroscopy, solid state UV-circular dichiroism (CD), and powder X-ray diffraction (XRD) spectra. The results indicated that the chiral crystals of cis-[Ni(NCS)2tren] were obtained by mirror symmetry-breaking crystallization, and the special chiral ring conformations (δδλ, λλδ) of the coordinated tripod-type tren ligands are responsible for the chiral origin of cis-[Ni(NCS)2tren]. The Cotton effects of Ni(II) complexes in the solid-state UV-CD spectra are presumably attributed to the π-π* and charge-transfer chromophores of the NCS- ligands by the chiral perturbation of the helical ring conformations and metal-centered chirality. According to the statistical results of solid-state CD spectra of cis-[Ni(NCS)2tren] for twenty batch syntheses, their enantiomeric excess (ee) values are between 39% and 100%.

Key words: Chirality, Mirror symmetry breaking, Ring conformational isomerism, Tris(2-aminoethyl)amine, Solid state CD spectroscopy

MSC2000: 

  • O641