Base-catalyzed thiol-epoxy reactions: Energetic and kinetic evaluations

IF 2.7 4区生物学 Q2 BIOCHEMICAL RESEARCH METHODS

Journal of molecular graphics & modelling Pub Date : 2024-12-24 DOI:10.1016/j.jmgm.2024.108933

Belma Gjergjizi Nallbani , Memet Vezir Kahraman , Isa Degirmenci

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Abstract

The mechanism of the base-catalyzed thiol-epoxide stage of the thiol-ene/thiol-epoxide curing process was investigated using quantum chemical tools. This study searched for conventional tertiary amines with low to medium basicity as initiators to control reaction rates and tailor industrial applications. Challenges arise from the stronger basicity of initiators, leading to an uncontrollable and short curing application period. This problem was put into quantitative data through kinetic and energetic studies for the first time. Furthermore, the base catalyst formulation of curing agents distinctively has a short pot life. More reactivity of terminal epoxy rings than internal ones was highlighted for the curing agents. It was revealed that the reactivity augments during the curing process while environmental polarity changes from higher to lower, which is one of the reasons that triggers an autocatalytic phenomenon. Electronegative atoms like fluorine on thiols significantly decrease the nucleophilicity of formed thiolate anion, enabling longer curing application.

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碱催化的硫醇-环氧反应：能量和动力学评价。

利用量子化学工具研究了巯基/巯基环氧化物固化过程中碱催化的硫醇-环氧化物阶段的机理。本研究寻找低至中等碱度的传统叔胺作为引发剂，以控制反应速率和定制工业应用。引发剂的碱性较强，导致固化时间不可控，且固化时间短。这一问题首次通过动力学和能量学的研究得到了定量的数据。此外，固化剂的碱催化剂配方具有明显的短锅寿命。固化剂的末端环氧环比内部环氧环反应性更强。结果表明，在固化过程中，随着环境极性由高到低的变化，反应性增强，这是引发自催化现象的原因之一。硫醇上的氟等电负性原子显著降低形成的硫酸阴离子的亲核性，使固化时间更长。

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来源期刊

Journal of molecular graphics & modelling 生物-计算机：跨学科应用

CiteScore

5.50

自引率

6.90%

发文量

216

审稿时长

35 days

期刊介绍： The Journal of Molecular Graphics and Modelling is devoted to the publication of papers on the uses of computers in theoretical investigations of molecular structure, function, interaction, and design. The scope of the journal includes all aspects of molecular modeling and computational chemistry, including, for instance, the study of molecular shape and properties, molecular simulations, protein and polymer engineering, drug design, materials design, structure-activity and structure-property relationships, database mining, and compound library design. As a primary research journal, JMGM seeks to bring new knowledge to the attention of our readers. As such, submissions to the journal need to not only report results, but must draw conclusions and explore implications of the work presented. Authors are strongly encouraged to bear this in mind when preparing manuscripts. Routine applications of standard modelling approaches, providing only very limited new scientific insight, will not meet our criteria for publication. Reproducibility of reported calculations is an important issue. Wherever possible, we urge authors to enhance their papers with Supplementary Data, for example, in QSAR studies machine-readable versions of molecular datasets or in the development of new force-field parameters versions of the topology and force field parameter files. Routine applications of existing methods that do not lead to genuinely new insight will not be considered.