Novel dirhodium coordination polymers: the impact of side chains on cyclopropanation

作者：Liu, Jiquan; Xu, Yeping; Groszewicz, Pedro B.; Brodrecht, Martin; Fasel, Claudia; Hofmann, Kathrin; Tan, Xijuan; Gutmann, Torsten^*; Buntkowsky, Gerd^*

来源：Catalysis Science & Technology, 2018, 8(20): 5190-5200.

DOI：10.1039/c8cy01493k

• METAL-ORGANIC FRAMEWORKS
• C-H INSERTION
• ASYMMETRIC CYCLOPROPANATION
• CARBENE TRANSFORMATIONS
• SOLID SUPPORT
• CATALYSTS
• NMR
• CARBOXYLATES
• FUNCTIONALIZATION
• IMMOBILIZATION

Seven novel dirhodium coordination polymers (Rh-2-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 H-1 C-13 cross polarization magic angle spinning nuclear magnetic resonance (CP MAS NMR) spectroscopy. Defect sites resulting from incomplete ligand substitution are revealed by F-19 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 Rh-2/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 Rh-2-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 Rh-2/O interactions and steric effects of side chains.

• 出版日期2018-10-21
• 单位西北大学; 长安大学