氰化氢(HCN)及其互变异构体异氰化物(HNC)与地球外化学有关,并可能与生物分子的起源有关。涉及这些分子的若干过程和反应取决于它们的分子间相互作用,其可导致聚集体和液体,尤其是由于氢键。因此,重要的是要理解,来描述,量化它们的氢键,主要是它们的性质和协同作用。提出了对HCN和HNC五聚体的所有线性复合物的系统研究。CCSD(T)/CBS能量计算,具有和不具有能量和几何形状的基集叠加误差(BSSE)校正,提供了一套合适的基准。基于密度泛函理论(DFT)的近似方法,例如BP86,PBE,TPSS,B3LYP,带有和不带有色散校正和远程校正的CAM-B3LYP,进行了评估,以描述相互作用能和协同作用。这些评估与选择用于液体模拟的DFT泛函相关。能量分解分析是在PBE/STO-TZ2P水平进行的,并提供了对氢键性质的见解,由静电成分主导。此外,获得了各种能量分量与相互作用能之间的线性关系。还发现协同能相对于相互作用能实际上是线性的,这可能与设计和/或校正经验力场有关。HCN/HNC低聚复合物中的图形抽象氢键。
Hydrogen cyanide (HCN) and its tautomer hydrogen isocyanide (HNC) are relevant for extraterrestrial chemistry and possible relation to the origin of biomolecules. Several processes and reactions involving these molecules depend on their intermolecular interactions that can lead to aggregates and liquids especially due to the hydrogen bonds. It is thus important to comprehend, to describe, and to quantify their hydrogen bonds, mainly their nature and the cooperativity effects. A systematic study of all linear complexes up to pentamers of HCN and HNC is presented. CCSD(T)/CBS energy calculations, with and without basis set superposition error (BSSE) corrections for energies and geometries, provided a suitable set of benchmarks. Approximated methods based on the density functional theory (DFT) such as BP86, PBE, TPSS, B3LYP, CAM-B3LYP with and without dispersion corrections and long-range corrections, were assessed to describe the interaction energies and cooperativity effects. These assessments are relevant to select DFT functionals for liquid simulations. Energy decomposition analysis was performed at the PBE/STO-TZ2P level and provided insights into the nature of the hydrogen bonds, which are dominated by the electrostatic component. In addition, several linear relationships between the various energy components and the interaction energy were obtained. The cooperativity energy was also found to be practically linear with respect to the interaction energy, which may be relevant for designing and/or correcting empirical force fields. Graphical Abstract Hydrogen bonds in HCN/HNC oligomeric complexesᅟ.