在 PdO(101)表面上，丙烷 σ-配合物对初级 C-H 键的断裂具有高选择性。
High selectivity for primary C-H bond cleavage of propane σ-complexes on the PdO(101) surface.
机构信息
Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States.
出版信息
J Am Chem Soc. 2011 Oct 12;133(40):16196-200. doi: 10.1021/ja206599k. Epub 2011 Sep 21.
We investigated regioselectivity in the initial C-H bond activation of propane σ-complexes on the PdO(101) surface using temperature programmed reaction spectroscopy (TPRS) experiments. We observe a significant kinetic isotope effect (KIE) in the initial C-H(D) bond cleavage of propane on PdO(101) such that the dissociation yield of C(3)H(8) is 2.7 times higher than that of C(3)D(8) at temperatures between 150 and 200 K. Measurements of the reactivity of (CH(3))(2)CD(2) and (CD(3))(2)CH(2) show that deuteration of the methyl groups is primarily responsible for the lower reactivity of C(3)D(8) relative to C(3)H(8), and thus that 1° C-H bond cleavage is the preferred pathway for propane activation on PdO(101). By analyzing the rate data within the context of a kinetic model for precursor-mediated dissociation, we estimate that 90% of the propane σ-complexes which dissociate on PdO(101) during TPRS do so by 1° C-H bond cleavage.
我们使用程序升温反应谱（TPRS）实验研究了在 PdO(101)表面上丙烷 σ-配合物初始 C-H 键活化的区域选择性。我们在 PdO(101)上观察到丙烷初始 C-H(D)键断裂的显著动力学同位素效应（KIE），使得在 150 至 200 K 之间，C(3)H(8)的离解产率比 C(3)D(8)高 2.7 倍。（CH(3))(2)CD(2)和（CD(3))(2)CH(2)的反应性测量表明，甲基的氘化主要导致 C(3)D(8)相对于 C(3)H(8)的反应性降低，因此 1° C-H 键断裂是 PdO(101)上丙烷活化的首选途径。通过在前驱体介导的离解动力学模型的背景下分析速率数据，我们估计在 TPRS 过程中在 PdO(101)上离解的丙烷 σ-配合物中，有 90%通过 1° C-H 键断裂离解。
Zotero 插件