Gómez Sara, Rojas-Valencia Natalia, Cappelli Chiara, Weinhold Frank, Restrepo Albeiro
Classe di Scienze, Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa, 56126, Pisa, Italy.
Departamento de Química, Universidad Nacional de Colombia, Av. Cra 30 45-03, Bogotá, 111321, Bogotá D.C., Colombia.
J Mol Model. 2024 Oct 23;30(11):382. doi: 10.1007/s00894-024-06169-8.
Nitrenium ions are intermediates in the metabolic routes producing the highly carcinogenic nitrosamines and binding to DNA molecules. The reaction mechanism of nitrenium molecules with explicit water molecules is sensibly dependent on the number of waters: when a second molecule is involved, it acts as a catalyst for the reaction, lowering intrinsic activation barriers regardless of the substituent. For all cases, the reaction force constants and reaction electron flux indicate highly synchronous reactions for . Conversely, for highly non-synchronous reactions are obtained, involving two separate proton transfers happening early and late in the reaction path. As a test case, for the simplest reactions, orbital interactions within the NBO paradigm, bond orders, and their derivatives indicate that each individual proton transfer is highly synchronous.
Molecular geometries were optimized and characterized at the B3LYP/6-311++G(d, p) level. Intrinsic reaction coordinates were calculated. CCSD(T) single point energies with the same basis were computed on all stationary points. The reaction force, reaction force constant, and reaction electron flux are used to study the evolution of the reacting systems. Natural bond orbitals are used to understand the primitive changes driving the reaction.
氮鎓离子是产生高致癌性亚硝胺并与DNA分子结合的代谢途径中的中间体。氮鎓分子与明确水分子的反应机制明显取决于水分子的数量：当涉及第二个分子时，它作为反应的催化剂，降低固有活化能垒，而与取代基无关。对于所有情况，反应力常数和反应电子通量表明 的反应具有高度同步性。相反，对于 ，得到的是高度非同步反应，涉及在反应路径早期和晚期发生的两个单独的质子转移。作为一个测试案例，对于最简单的 反应，NBO范式内的轨道相互作用、键级及其导数表明每个单独的质子转移都是高度同步的。
在B3LYP/6 - 311++G(d, p)水平上对分子几何结构进行优化和表征。计算了内禀反应坐标。在所有驻点上使用相同基组计算CCSD(T)单点能量。使用反应力、反应力常数和反应电子通量来研究反应体系的演化。使用自然键轨道来理解驱动反应的原始变化。
