Grinevich Oksana I, Volkov Victor V, Buryak Aleksey K
A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, Moscow, GSP-1, 119071, Russian Federation.
Bereozovaya 2a, Konstantinivo, Moscow Region, 140207, Russian Federation.
Phys Chem Chem Phys. 2022 Dec 14;24(48):29712-29720. doi: 10.1039/d2cp05096j.
We conduct quantum studies of adsorption of diazine heterocycles on graphene to discuss experimental thermodynamics of gas-phase adsorption of pyridazine, pyrimidine and pyrazine on graphitized thermal carbon black, as reported previously. Using Born-Oppenheimer molecular dynamics and density functional studies, we characterize structural and electronic tendencies of the heterocycles on graphene. The theoretical studies predict the adsorption of pyridazine, pyrazine and pyrimidine to cause electronic perturbations of dipole, quadrupole and mixed spatial characters, respectively, resulting in a red shift of the electronic components of the heterocycles to modulate graphene electronics upon admixing of diazine orbital components with the π states of the substrate. Investigating the thermodynamics of adsorption further involves calculating Henry's constant with the expression of the uniform surface limit: using experimental data, we estimate binding energies and force derivatives with respect to the surface normal. The extracted association energies agree with the results of Lennard-Jones potential calculations. Together, the reported pyridazine anomalous retention required the association force constant to be lower compared with values for the other diazines. Exploring energies of intermolecular relations, we ascribe the pyridazine anomalous retention to possibility of the formation of pyridazine dimers: when on the surface, only for pyridazine, the computed benefit of pairing is larger than the energy of molecular association with graphene.
我们对二嗪杂环在石墨烯上的吸附进行了量子研究，以讨论哒嗪、嘧啶和吡嗪在石墨化热炭黑上的气相吸附实验热力学，如先前报道。利用玻恩-奥本海默分子动力学和密度泛函研究，我们表征了杂环在石墨烯上的结构和电子趋势。理论研究预测，哒嗪、吡嗪和嘧啶的吸附分别会引起偶极、四极和混合空间特征的电子扰动，导致杂环电子成分发生红移，从而在二嗪轨道成分与基底的π态混合时调节石墨烯电子学。进一步研究吸附热力学涉及用均匀表面极限表达式计算亨利常数：利用实验数据，我们估计了结合能和相对于表面法线的力导数。提取的缔合能与 Lennard-Jones 势计算结果一致。综合来看，所报道的哒嗪异常保留现象要求其缔合力常数比其他二嗪的值更低。通过探索分子间相互作用的能量，我们将哒嗪的异常保留归因于形成哒嗪二聚体的可能性：当在表面时，仅对于哒嗪，计算得到的配对益处大于分子与石墨烯缔合的能量。
