Kalchevski Dobromir A, Kolev Stefan K, Trifonov Dimitar V, Grozev Ivan G, Aleksandrov Hristiyan A, Popov Valentin N, Milenov Teodor I
"Acad. E. Djakov" Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria.
Faculty of Chemistry and Pharmacy, Sofia University "St. Kliment Ohridski", 1 J. Bourchier Blvd., 1164 Sofia, Bulgaria.
Nanomaterials (Basel). 2025 Jul 17;15(14):1110. doi: 10.3390/nano15141110.
We present a theoretical model of the hydrogenation and amination of a primal carbon cluster of the tangled polycyclic type. Hydrogen atoms were introduced via H, while the nitrogen source was NH. The initial chemical processes were modeled using Born-Oppenheimer Molecular Dynamics. Metadynamics was employed to accelerate the saturation. The reactions were characterized in terms of barriers, topology, and intricate changes in the electronic structure. All transition states were identified. Multiple mechanisms for each type of reaction were discovered. Occasional unbiased changes in the carbon skeleton, induced by the guided processes, were observed. The initial addition reactions had no barriers due to the instability and high reactivity of the carbon structure. The final product of barrierless hydrogen saturation was CH. This molecule included multiple isolated double bonds, a medium-sized conjugated π system, and no triple bonds. Ammonia additions resulted in quaternary ammonium groups and primary amino groups. In the subsequent amination, a barrier appeared in fewer steps than in repetitive hydrogenation. The final product of barrierless saturation with NH was CH(NH)NH. Further amination was characterized by a forward free-energy barrier of an order of magnitude larger than the reverse reaction, and the product was found to be unstable.
我们提出了一种关于缠结多环型原始碳簇氢化和胺化的理论模型。氢原子通过H引入，而氮源为NH。初始化学过程采用玻恩-奥本海默分子动力学进行建模。使用元动力学来加速饱和过程。从势垒、拓扑结构以及电子结构的复杂变化等方面对反应进行了表征。识别出了所有过渡态。发现了每种反应类型的多种机制。观察到了由引导过程引起的碳骨架偶尔的无偏变化。由于碳结构的不稳定性和高反应活性，初始加成反应没有势垒。无势垒氢饱和的最终产物是CH。该分子包含多个孤立双键、一个中等大小的共轭π体系，且没有三键。氨的加成产生了季铵基团和伯氨基。在随后的胺化过程中，与重复氢化相比，势垒出现的步骤更少。用NH进行无势垒饱和的最终产物是CH(NH)NH。进一步的胺化表现为正向自由能势垒比逆向反应大一个数量级，并且发现产物不稳定。
