分会

第二十四分会：化学中的量子与经典动力学

摘要

Described herein is a comparative theoretical study on an Ohki-Tatsumi complex, a cationic Ru(II) complex with a tethered thiolate ligand ( [Ru-S] = [(DmpS)Ru(PiPr3)][BArF4]; Dmp = 2,6-(dimesityl)2C6H3; ArF = 3,5-(CF3)2C6H3), catalyzed dehydrogenative C(sp)-H functionalizations of a terminal alkyne1 with group 14 based hydrides (HEEt3; E = Si, Ge, Sn). The calculations indicate that the energy barriers for heterolytic cleavage of the H-EEt3 bonds at the Ru-S sites2 of the Ohki-Tatsumi complex highly vary depending on the group 14 elements from 3.8 kcal/mol (E = Sn) to 10.5 kcal/mol (E = Ge) and 18.5 kcal/mol (E = Si), where Ru and S elements cooperatively serve as Lewis acid and base, repsectively. Likewise, the transfer of the group 14 cation (Et3E+) to the C-C triple bond to generate the element stabilized vinyl cations, the rate-determining step of the overall reaction, is predicted to be susceptible to the element’s identity [∆G‡ = 23.3 for Sn < 37.2 for Ge < 49.5 for Si (kcal/mol)]. The key transition states determining the reaction path towards either the C(sp)-H elementation or the hydroelementation3 of a terminal alkyne, are compared in terms of energy and structure within each system of the group 14 hydrides, and the Distortion/Interaction Activation Strain (DIAS) model analysis sheds light on the origin of the experimentally observed kinetic preference towards the dehydrogenative C-H stannylation over the hydrostannation.

关键词

DFT calculation;Dehydrogenation;DIAS

线上墙报仅限年会已缴费参会代表观看。

您还没有登录，请您先 点击这里登录