Letter. On the activation of [CrCl3{R-SN(H)S-R}] catalysts for selective trimerization of ethene: a freeze-quench Cr K-edge XAFS study
ACS Catalysis(2014)
摘要
Homogeneous chromium catalysts for the selective conversion of ethene to hex-1-ene are formed from Cr(III) reagents, aminothioether ligands of the type HN(CH2CH2SR)(2), and aluminum reagents. In this study, the early activation steps are investigated by EPR, UVvisible, and Cr K-edge XAFS spectroscopy; rapid stopped-flow mixing and a freeze-quench allows good quality EXAFS analysis of a species formed in similar to 1 s of reaction. This is shown to involve reduction to Cr(II) and deprotonation of a NH group of the auxiliary ligand. This 4-coordinate metal center may act as precursor for the coordination of ethene and subsequent selective oligomerization.
更多查看译文
关键词
homogeneous catalysis,chromium,oligomerization,XAFS spectroscopy,DFT calculations
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要