Millam Evan, Deligkaris Christos, Wade Edmir O
Department of Chemistry and Biochemistry, University of Southern Indiana, Evansville, IN 47712, USA.
Department of Geology and Physics, University of Southern Indiana, Evansville, IN 47712, USA.
R Soc Open Sci. 2024 Sep 11;11(9):230975. doi: 10.1098/rsos.230975. eCollection 2024 Sep.
Recent work on the diazonium ion metabolite of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNKDI) suggests that 5-(pyridin-3-yl)-3,4-dihydro-2-furan-1-ium (NNKFI) may form from NNKDI via an intramolecular reaction. NNKDI is an important carcinogen whose role as an alkylating agent has received significant attention. While there is some experimental evidence supporting NNKFI's production , it has not yet been directly observed. Little is known about NNKFI's structure and reactivity. We report the first examination of this ion. Our study utilized Kohn-Sham density functional theory (B3LYP/6-311G**) and coupled cluster theory (CCSD/6-31G*) to produce energy-optimized structures, vibrational normal modes and molecular orbitals for NNKFI. To gain insight into the chemical properties of this species, we calculated electrostatic potential surfaces, natural population analysis charges and local Fukui indices. We report data and results for NNKFI's and conformers. Our work confirms C5 as the preferred site for nucleophilic attack in NNKFI. Stretching motions and predicted bond lengths near O1 are consistent with a somewhat weakened carbonyl structure in this ion. Partial charges, electrostatic potential surfaces and local Fukui indices reveal delocalization of cationic charge on the furanium moiety and notable carbocation character at C5.
近期对4-(甲基亚硝基氨基)-1-(3-吡啶基)-1-丁酮重氮离子代谢物（NNKDI）的研究表明，5-(吡啶-3-基)-3,4-二氢-2-呋喃鎓离子（NNKFI）可能通过分子内反应由NNKDI形成。NNKDI是一种重要的致癌物，其作为烷基化剂的作用受到了广泛关注。虽然有一些实验证据支持NNKFI的生成，但尚未直接观察到。人们对NNKFI的结构和反应性知之甚少。我们首次对该离子进行了研究。我们的研究利用了Kohn-Sham密度泛函理论（B3LYP/6-311G**）和耦合簇理论（CCSD/6-31G*）来生成NNKFI的能量优化结构、振动简正模式和分子轨道。为了深入了解该物种的化学性质，我们计算了静电势表面、自然布居分析电荷和局部福井指数。我们报告了NNKFI及其构象异构体的数据和结果。我们的工作证实了C5是NNKFI中亲核进攻的首选位点。O1附近的伸缩运动和预测键长与该离子中羰基结构有所减弱一致。部分电荷、静电势表面和局部福井指数揭示了呋喃鎓部分阳离子电荷的离域以及C5处显著的碳正离子特征。
