Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
Proc Natl Acad Sci U S A. 2012 Nov 6;109(45):18295-9. doi: 10.1073/pnas.1207600109. Epub 2012 Oct 22.
We have applied an ambient ionization technique, desorption electrospray ionization MS, to identify transient reactive species of an archetypal C-H amination reaction catalyzed by a dirhodium tetracarboxylate complex. Using this analytical method, we have detected previously proposed short-lived reaction intermediates, including two nitrenoid complexes that differ in oxidation state. Our findings suggest that an Rh-nitrene oxidant can react with hydrocarbon substrates through a hydrogen atom abstraction pathway and raise the intriguing possibility that two catalytic C-H amination pathways may be operative in a typical bulk solution reaction. As highlighted by these results, desorption electrospray ionization MS should have broad applicability for the mechanistic study of catalytic processes.
我们应用了一种环境电离技术，即解吸电喷雾电离质谱（DESI-MS），来鉴定由二钌四羧酸配合物催化的典型 C-H 氨化反应的瞬态反应性物种。使用这种分析方法，我们已经检测到了以前提出的短寿命反应中间体，包括两种氧化态不同的氮烯配合物。我们的发现表明，Rh-氮烯氧化剂可以通过氢原子提取途径与碳氢化合物底物反应，并提出了一个有趣的可能性，即在典型的均相溶液反应中可能存在两种催化 C-H 氨化途径。正如这些结果所强调的，解吸电喷雾电离质谱（DESI-MS）应该在催化过程的机理研究中具有广泛的适用性。
