星际空间中由氨基乙腈生成甘氨酸的机制。

Mechanisms of glycine formation from aminoacetonitrile in space.

机构信息

Department of Chemistry, Dongguk University-Seoul, Seoul 04620, Republic of Korea.

出版信息

Phys Chem Chem Phys. 2023 Jun 15;25(23):16001-16008. doi: 10.1039/d3cp01155k.

Abstract

The potential energy surfaces for the formation of glycine (Gly) or its precursors, such as Gly radical cation and deprotonated Gly, starting from aminoacetonitrile (NHCHCN) or deprotonated aminoacetonitrile were determined by CBS-QB3 calculation. The reaction of NHCHCN + HO˙ + HO gave mainly unwanted products other than Gly or its precursors. The reactions of ˙NHCHCN + 2HO, NH˙CHCN + 2HO, or NHCHCN + ˙OH + HO, led to Gly or its precursors as one of the main products. The overall activation barriers were 229 kJ mol, 216 kJ mol, and 118 kJ mol, respectively. A barrierless pathway for the formation of Gly from the reaction of NHCHCN + ˙OH + HO with a catalytic HO was found, strongly suggesting that Gly can be formed thermally from NHCHCN and ˙OH on icy grain surfaces in the interstellar medium.

摘要

通过 CBS-QB3 计算，确定了由氨基乙腈（NHCHCN）或去质子化的氨基乙腈起始，形成甘氨酸（Gly）或其前体（如 Gly 自由基阳离子和去质子化的 Gly）的势能面。NHCHCN + HO˙ + HO 的反应主要生成了除 Gly 或其前体以外的不需要的产物。反应 ˙NHCHCN + 2HO、NH˙CHCN + 2HO 或 NHCHCN + ˙OH + HO 导致 Gly 或其前体作为主要产物之一。总活化能垒分别为 229 kJ/mol、216 kJ/mol 和 118 kJ/mol。发现了 NHCHCN + ˙OH + HO 与催化 HO 反应形成 Gly 的无势垒途径，强烈表明甘氨酸可以在星际介质中冰粒表面的 NHCHCN 和 ˙OH 之间通过热反应形成。