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对草甘二聚化的计算研究:溶剂的机制和作用

Sondes Meddeb-Limem¹, Arij Ben Fredj¹

¹Unité de recherche de Modélisation en Sciences Fondamentales et Didactiques, équipe de Chimie Théorique et Réactivité UR14ES10, Institut Préparatoire aux études d'Ingénieurs d'El Manar, Université de Tunis El Manar B. P. 244 El Manar II 2092 Tunis Tunisia erijbf@yahoo.fr +216 72 593 450 +216 72 593 450 + 216 54744256.

|July 24, 2024

概括

计算分析显示,草甘 (Glyph) 可以在各种介质中形成稳定的二次体,特别是DZC结构. 溶剂效应显著影响了Glyph的二分化,而水化则与此相反,这与Glyph单体的发现相反.

科学领域:

计算化学的计算化学
物理化学物理化学
环境化学环境化学

背景情况:

草甘 (Glyph) 是一种广泛使用的除草剂.
了解Glyph在不同环境中的聚合行为至关重要.
之前对Glyph单体的研究对二元形成的洞察力有限.

研究的目的:

通过计算来研究草甘二聚物的结构和稳定性.
在各种介质中分析草甘二聚化的能量.
为了探索Glyph二次体中的 tautomerism 和质子转移机制.

主要方法:

使用B3LYP-D3/6-311++G(2d,2p) 理论水平进行量子化学计算.
基于密度 (SMD) 的溶解模型用于溶液相计算.
对二次体符合体的优化几何,相对潜力和自由能量进行分析.

主要成果:

预计存在包括非电离 (DN),阴离子 (AC) 和双 (DZP,DZC) 形式在内的草甘二元体.
DZC二聚体,具有中心对称的碳酸二聚离子排列,是所有介质中最稳定的形式.
在水溶液中,化稳定了DZP和AC二聚体类型,而环素则有利于二聚化.
确定了质子转移机制 (DZP AC DZC),其中DZC更容易在水中转移.

结论:

溶剂的极性对草甘二分化能量产生了重大影响;水化阻碍了它,而非极性溶剂则促进了它.
在水溶液中,在高度下,DZC二聚体及其分聚体 (DZP,AC) 可能比zwitterionic单聚体更为普遍.
这些发现挑战了关于水性环境中草甘单体二元平衡的现有文献.

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