论文标题
[PO（H $ _2 $ O）$ _ N $] $^{4+} $和[POCL $ _N $] $^{4-n-n} $ COMPLIENT在[PO（H $ _2 $ O）$ _ N $]中的几何形状，交互能和键
Geometries, interaction energies and bonding in [Po(H$_2$O)$_n$]$^{4+}$ and [PoCl$_n$]$^{4-n}$ complexes
论文作者
论文摘要
polonium（Z = 84）是地球上最稀有的元素之一。在发现它的一个多世纪后，其化学反应仍然鲜为人知，甚至基本问题尚未令人满意地解决。在这项工作中，我们对基本polonium（IV）物种的几何形状，相互作用能量和键合进行系统研究，即水合[PO（H $ _2 $ O）$ _ N $] $^{4+} $并氯化[POCL $ _N $ _N $] $^{4-N} $ COMPLECTES YE GAS-COMPLECT ELTACTER ELLECTONE ELLECTASE。我们表明，虽然多达九个水分子可以适合polonium（IV）离子的第一个配位球体，但其协调球已经可以填充八个氯化物配体。利用先前的理论研究，基于相互作用能和键距离的重点方法研究使我们能够验证MP2/def2- TZVP理论水平，以实现未来的地面研究。在讨论了与配体数量相同数量的配合物之间的相似性和差异之后，我们在分子（QTAIM）方式中对原子量子理论进行了MP2电子密度的拓扑分析。虽然水配合物显示出闭合壳相互作用的典型签名，但我们揭示了大型PO-CL Decalisation指数，尤其是在假设的[POCL] $^{3+} $ COMFFELK中。这种“增强”的共价为对相应键距离的显着自旋轨道耦合（SOC）效应打开了道路，这已经通过两种独立的方法（即一种先验性和一个后验）进行了研究。最终，我们最终强调，尽管SOC可能不会影响高协调的polonium（IV）络合物的几何形状，但在低音协调的情况下，绝对不应忽略它。
Polonium (Z = 84) is one of the rarest elements on Earth. More than a century after its discovery, its chemistry remains poorly known and even basic questions are not yet satisfactorily addressed. In this work, we perform a systematic study of the geometries, interactions energies and bonding in basic polonium(IV) species, namely the hydrated [Po(H$_2$O)$_n$]$^{4+}$ and chlorinated [PoCl$_n$]$^{4-n}$ complexes by means of gas-phase electronic structure calculations. We show that while up to nine water molecules can fit in the first coordination sphere of the polonium(IV) ion, its coordination sphere can already be filled with eight chloride ligands. Capitalising on previous theoretical studies, a focused methodological study based on interaction energies and bond distances allows us to validate the MP2/def2- TZVP level of theory for future ground-state studies. After discussing similarities and differences between complexes with the same number of ligands, we perform topological analyses of the MP2 electron densities in the quantum theory of atoms in molecules (QTAIM) fashion. While the water complexes display typical signatures of closed-shell interactions, we reveal large Po-Cl delocalisation indices, especially in the hypothetical [PoCl]$^{3+}$ complex. This "enhanced" covalency opens the way for a significant spin-orbit coupling (SOC) effect on the corresponding bond distance, which has been studied by two independent approaches (i.e. one a priori and one a posteriori). We finally conclude by stressing that while the SOC may not affect much the geometries of high-coordinated polonium(IV) complexes, it should definitely not be neglected in the case of low-coordinated ones.
