管理提醒： 本帖被 chenshuuu 执行加亮操作(2010-12-27)
Researchers at the University of Arizona led by Lucy M. Ziurys have captured the first detailed structure of a molecule formed by insertion of a transition metal into a C–H bond of methane (J. Am. Chem. Soc., DOI: 10.1021/ja106121v). The achievement gives new insight into the mechanis of catalytic C–C and C–H bond activations that are important in organic synthesis. Scientists have previously tried multiple approaches for obtaining a structural snapshot of metal-methane insertion complexes. Those efforts have been limited until now to photochemical reactions in low-temperature inert-gas matrices or gas-phase molecular beam experiments, which can help researchers tell that metal insertion has taken place but can’t provide exact structural details about the insertion products. Ziurys and coworkers produced HZnCH3 in the gas phase by reacting Zn(CH3)2 with H2 and CH4 in an electric discharge or by reacting zinc vapor with CH4 in an electric discharge. The researchers determined HZnCH3’s precise structure by examining zinc, carbon, and hydrogen isotopic variations in high-resolution rotational spectra recorded using a combination of microwave spectroscopy techniques. They found that HZnCH3 is relatively stable, has covalent H–Zn and Zn–C bonds, and likely forms by direct Zn insertion into a C–H bond rather than first forming ZnH or ZnCH3 species.
