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Construction of tetrahedral chiral-at-metal complexes towards asymmetric light-driven redox catalysis

构建四面体手性金属配合物以实现不对称光驱动氧化还原催化

基本信息

批准号：
22KJ0852
负责人：
LIU Yuanfei
金额：
$ 1.09万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for JSPS Fellows
财政年份：
2023
资助国家：
日本
起止时间：
2023-03-08 至 2024-03-31
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-22KJ0852/
关键词：
nickel cobalt chiral-at-metal tetrahedral geometry redox-active spontaneous resolution

项目摘要

In one year research, I mainly focus on construction and resolution of redox-active chiral-at-nickel(II) and chiral-at-cobalt(II) complexes.First, I constructed two tetrahedral chiral-at-nickel(II) complexes using an unsymmetrical, achiral tridentate ligand and characterized them by NMR, ESI-MS, single-crystal XRD and UV-vis absorption spectroscopy. The structural information was carefully elucidated. The complexes adopt a tetrahedral geometry and exhibit redox activity as well as visible-light absorption. Also, they are capable of ligand exchange for substrate activation.Second, I succeeded in spontaneous resolution of S/R-[NiL(ClLi(thf)2)] complex to conglomerate crystals at low temperature. I optimized the crystallization conditions and elucidated the crystallographic structure. I found that hydrogen bondings are essential to achieve spontaneous resolution. Starting from achiral building blocks, the ligands and nickel ions assemble chiral-at-metal complexes, 1D chiral helices, 3D chiral suprastructure and finally homochiral crystals in a highly asymmetric manner. This is related to the origin of homochirality in biological systems in ancient earth and sheds light on the concept of crystal engineering.I also successfully constructed a tetrahedral chiral-at-cobalt(II) complex and charactered it by NMR, ESI-MS, single-crystal XRD, UV-vis absorption spectroscopy. Together with silver salts, the complex was found to be capable for carbon-carbon bond cleavage of 1,2-diarylethylenediamine. The reaction condition is under optimization currently.

在一年的研究中，我主要致力于氧化还原活性手性金属镍(II)和手性金属钴(II)配合物的构建和拆分。首先，我用一个不对称的非手性三齿配体构建了两个四面体手性金属镍(II)配合物，并用核磁共振、ESI-MS、单晶X射线衍射法和紫外-可见吸收光谱对其进行了表征。对其结构信息进行了详细的阐述。配合物采用四面体构型，表现出氧化还原活性和可见光吸收。其次，我成功地实现了S/R-[NiL(四氢呋喃)2]络合物在低温下自发拆分为团聚晶体。对结晶条件进行了优化，并对晶体结构进行了分析。我发现氢键是实现自发分解的关键。配体和镍离子从非手性构件开始，以高度不对称的方式组装手性金属配合物、一维手性螺旋、三维手性超结构，最终组装成同手性晶体。这与地球古代生物系统的同色性起源有关，并揭示了晶体工程的概念。我还成功地构建了四面体手性钴(II)配合物，并用核磁共振、ESI-MS、单晶X射线衍射、UV-Vis吸收光谱对其进行了表征。与银盐一起，发现该络合物能够裂解1，2-二芳基乙二胺的碳-碳键。目前，反应条件正在优化中。