Novel Dirhodium Coordination Polymers: The Impact of Side Chains on Cyclopropanation
Novel Dirhodium Coordination Polymers: The Impact of Side Chains on Cyclopropanation
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DOI：
10.1039/c8cy01493k
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发表时间：
2018-10
影响因子：
5
通讯作者：
Jiquan Liu;Yeping Xu;P. Groszewicz;M. Brodrecht;C. Fasel;K. Hofmann;X. Tan;T. Gutmann;G. Buntkowsky
中科院分区：
文献类型：
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作者：
Jiquan Liu;Yeping Xu;P. Groszewicz;M. Brodrecht;C. Fasel;K. Hofmann;X. Tan;T. Gutmann;G. Buntkowsky
通过使用双位配体连接二铑节点制备了七种新型二铑配位聚合物（Rh2–Ln）（n = 1–7）。衰减全反射傅里叶变换红外（ATR-FTIR）和1H→13C交叉偏振魔角旋转核磁共振（CP MAS NMR）光谱证实了框架的形成。 19F MAS NMR 揭示了配体取代不完全导致的缺陷位点。通过扫描电子显微镜 (SEM) 和 X 射线衍射 (XRD) 分析了所得固体中骨架的随机堆积行为。通过漫反射紫外可见光 (DR-UV-vis) 光谱和 X 射线光电子能谱 (XPS) 研究了相邻层中的 Rh2/O 相互作用。这种相互作用与了解各种 Rh2-Ln 催化剂在苯乙烯与重氮乙酸乙酯 (EDA) 环丙烷化反应中的催化行为相关。在这种情况下，通过考虑层间 Rh2/O 相互作用和侧链的空间效应来讨论结构-反应性关系。
Seven novel dirhodium coordination polymers (Rh2–Ln) (n = 1–7) are prepared by employing bitopic ligands to connect dirhodium nodes. The formation of the framework is confirmed by attenuated total reflectance Fourier transform infrared (ATR-FTIR) and 1H → 13C cross polarization magic angle spinning nuclear magnetic resonance (CP MAS NMR) spectroscopy. Defect sites resulting from incomplete ligand substitution are revealed by 19F MAS NMR. The random stacking behavior of the frameworks in the obtained solid is analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The Rh2/O interaction in neighboring layers is investigated by diffuse reflectance ultra-violet visible light (DR-UV-vis) spectroscopy and X-ray photoelectron spectroscopy (XPS). This interaction is relevant to understand the catalytic behavior of various Rh2–Ln catalysts in the cyclopropanation of styrene with ethyl diazoacetate (EDA). In this context, the structure-reactivity relationship is discussed by taking into consideration both interlayer Rh2/O interactions and steric effects of side chains.