Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg SE-412 96, Sweden.
J Phys Chem A. 2023 May 25;127(20):4503-4510. doi: 10.1021/acs.jpca.3c01504. Epub 2023 May 11.
Products of hydrogen cyanide (HCN) reactivity are suspected to play important roles in astrochemistry and, possibly, the origin of life. The composition, chemical structure, and mechanistic details for formation of products from HCN's self-reactions have, however, proven elusive for decades. Here, we elucidate base-catalyzed reaction mechanisms for the formation of diaminomaleonitrile and polyimine in liquid HCN using ab initio molecular dynamics simulations. Both materials are proposed as key intermediates for driving further chemical evolution. The formation of these materials is predicted to proceed at similar rates, thereby offering an explanation of how HCN's self-reactions can diversify quickly under kinetic control. Knowledge of these reaction routes provides a basis for rationalizing subsequent reactivity in astrochemical environments such as on Saturn's moon Titan, in the subsurface of comets, in exoplanet atmospheres, and on the early Earth.
氰化氢（HCN）反应的产物被怀疑在天体化学中起着重要作用，并且可能是生命起源的关键。然而，几十年来，HCN 自反应产物的组成、化学结构和形成的机理细节一直难以捉摸。在这里，我们使用从头算分子动力学模拟阐明了在液态 HCN 中二氨基丙二腈和聚亚胺形成的碱催化反应机制。这两种材料都被提议作为推动进一步化学演化的关键中间体。这些材料的形成被预测具有相似的速率，从而解释了 HCN 自反应如何在动力学控制下迅速多样化。这些反应途径的知识为在天体化学环境中（如土星卫星泰坦上、彗星的地下、系外行星大气中和早期地球上）合理化后续反应提供了基础。
