A recent theoretical investigation has uncovered various mechanisms of reactivity involving a primal carbon cluster of the tangled polycyclic variety, particularly in relation to hydrogen and ammonia interactions. This study applied advanced computational methods to analyze how hydrogen atoms, introduced through H2, and ammonia (NH3) interact with these carbon structures.
The research utilized Born–Oppenheimer Molecular Dynamics to model the initial stages of chemical reactions. To enhance the simulation of reaction progress, metadynamics was employed, allowing for the exploration of the energy landscape and enabling the identification of transition states.
Findings revealed that the reactions were characterized by their energy barriers, topological features, and significant alterations in the electronic structure of the carbon cluster. Notably, multiple reaction pathways were identified for each type of interaction. Interestingly, the carbon skeleton occasionally underwent unbiased transformations due to the guided processes observed during the reactions.
The initial hydrogen addition reactions were found to be barrierless, attributed to the inherent instability and high reactivity of the carbon structure. The end product from these reactions was identified as C25H26, which featured multiple isolated double bonds and a moderately sized conjugated π system, while lacking any triple bonds.
In contrast, the addition of ammonia led to the formation of quaternary ammonium and primary amino groups. The subsequent amination process encountered a barrier that was present in fewer steps than those observed during the repetitive hydrogenation. The resultant product from the barrierless reaction with NH3 was C25H2(NH3)2NH2. Further amination processes showed a forward free-energy barrier significantly larger than the reverse reaction, indicating that the final product was unstable.
This study provides valuable insights into the complex reactivity of carbon clusters in extraterrestrial environments, contributing to our understanding of organic chemistry in space and the potential for the emergence of life.
