Academic Department of Chemistry and Biology, Universidade Tecnológica Federal do Paraná, 81280-340, Curitiba-PR, Brazil.
Department of Chemistry, Universidade Federal do Paraná, CP 19081, CEP 81531-990, Curitiba-PR, Brazil.
Chemistry. 2020 Apr 16;26(22):5017-5026. doi: 10.1002/chem.201905379. Epub 2020 Mar 30.
The harmful impact caused by pesticides on human health and the environment necessitates the development of efficient degradation processes and control of prohibited stocks of such substances. Organophosphates (OPs) are among the most used agrochemicals in the world and their degradation can proceed through several possible pathways. Investigating the reactivity of OPs with nucleophilic species allows one to propose new and efficient catalyst scaffolds for use in detoxification. In light of the remarkable catalytic activity of imidazole (IMZ) at promoting dephosphorylation processes of OPs, the reactivity of 4(5)-hydroxymethylimidazole (HMZ) with diethyl-2,4-dinitrophenylphosphate (DEDNPP) and Paraoxon are evaluated by combining experimental and theoretical approaches. It is observed that HMZ is an efficient and regiospecific catalyst with reactivity modulated by competing tautomers. To propose an optimal IMZ-based catalyst, quantum chemical calculations were performed for monosubstituted 4(5)IMZ derivatives that might cleave DEDNPP. Both inductive effects and hydrogen bonding by the substituents are shown to influence barriers and mechanisms.
农药对人类健康和环境造成的有害影响，需要开发有效的降解过程和控制这些物质的违禁库存。有机磷（OPs）是世界上使用最广泛的农用化学品之一，它们的降解可以通过几种可能的途径进行。研究 OPs 与亲核物种的反应性，可以为解毒应用提出新的和有效的催化剂支架。鉴于咪唑（IMZ）在促进 OPs 的去磷酸化过程中表现出显著的催化活性，通过实验和理论相结合的方法，评估了 4(5)-羟甲基咪唑（HMZ）与二乙基-2,4-二硝基苯膦（DEDNPP）和对氧磷的反应性。结果表明，HMZ 是一种高效且区域选择性的催化剂，其反应性受竞争互变异构体的调节。为了提出一种基于 IMZ 的最佳催化剂，对可能裂解 DEDNPP 的单取代 4(5)IMZ 衍生物进行了量子化学计算。结果表明，取代基的诱导效应和氢键都影响着能垒和反应机制。
