Kuntar Subrahmanya Prasad, Ghosh Ayan, Ghanty Tapan K
Bio Science Group, Bhabha Atomic Research Centre, Mumbai 400 085, India.
Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400 094, India.
Phys Chem Chem Phys. 2022 Aug 31;24(34):20466-20479. doi: 10.1039/d2cp02329f.
The scarce literature on noble gas (Ng)-phosphorous chemical bonding and our recent theoretical prediction of the FNgP molecule motivate us to explore a unique novel class of neutral noble gas-inserted phosphorus trifluoride and pentafluoride molecules, , FNgPF and FNgPF (Ng = Ar, Kr, Xe, and Rn). The predicted molecules have been designed by inserting an Ng atom between the F and P atoms in the PF and PF molecules. The minima and saddle point geometries of all the FNgPF ( = 2 and 4) molecules have been optimized using density functional theory (DFT) and second-order Møller-Plesset perturbation theory (MP2). The coupled cluster theory (CCSD(T)) method is also used to optimize the FNgPF molecules to test the performance of the above-mentioned methods. The predicted FNgPF and FNgPF molecules are found to be energetically stable with respect to all the probable 2-body and 3-body dissociation channels, except for the one leading to the global minimum products (Ng + PF and Ng + PF). The existence of large barrier heights corresponding to the saddle point geometries is responsible for the kinetic stability of the metastable FNgPF ( = 2 and 4) molecules, which prevents them from dissociating into their global minima products. The optimized structural parameters, energetics and harmonic vibrational frequency analysis suggest that the Ng-P bond is covalent in nature, while the F-Ng bond is mostly ionic in nature with some degree of covalency in the predicted molecules. In fact, the Ng-P bond length in the experimentally observed Ng-PF van der Waals complex is reduced significantly in the isomeric FNgPF molecule, almost leading to a conventional covalent Ng-P bond ( 4.152 . 2.413 Å for the Kr-P bond). Furthermore, the charge distribution and the AIM analysis also confirm the above-mentioned conclusion and indicate that the predicted FNgPF and FNgPF molecules can be represented as [F][NgPF] and [F][NgPF], respectively. All the computational results strongly reinforce the possible existence of these predicted FNgPF ( = 2 and 4) molecules and clearly indicate that it may be possible to synthesize and characterize these molecules under suitable experimental technique(s).
关于稀有气体（Ng）与磷化学键合的文献稀缺，以及我们最近对FNgP分子的理论预测，促使我们探索一类独特的新型中性稀有气体插入的三氟化磷和五氟化磷分子，即FNgPF和FNgPF（Ng = Ar、Kr、Xe和Rn）。预测的分子是通过在PF和PF分子中的F和P原子之间插入一个Ng原子而设计的。使用密度泛函理论（DFT）和二阶Møller-Plesset微扰理论（MP2）对所有FNgPF（ = 2和4）分子的极小值和鞍点几何结构进行了优化。耦合簇理论（CCSD(T)）方法也用于优化FNgPF分子，以测试上述方法的性能。发现预测的FNgPF和FNgPF分子相对于所有可能的二体和三体解离通道在能量上是稳定的，但导致全局最小产物（Ng + PF和Ng + PF）的通道除外。对应于鞍点几何结构的大势垒高度的存在是亚稳FNgPF（ = 2和4）分子动力学稳定性的原因，这阻止了它们解离为全局最小产物。优化的结构参数、能量学和谐波振动频率分析表明，Ng-P键本质上是共价键，而F-Ng键在预测的分子中大多是离子键，有一定程度的共价性。事实上，在实验观察到的Ng-PF范德华络合物中，Ng-P键长在异构体FNgPF分子中显著缩短，几乎形成了传统的共价Ng-P键（对于Kr-P键， 4.152. 2.413 Å）。此外，电荷分布和AIM分析也证实了上述结论，并表明预测的FNgPF和FNgPF分子可以分别表示为[F][NgPF]和[F][NgPF]。所有的计算结果都有力地支持了这些预测的FNgPF（ = 2和4）分子可能存在，并清楚地表明在合适的实验技术下有可能合成和表征这些分子。
