Cui Li-Juan, Liu Xin-Bo, Zhang Hui-Yu, Yan Bing, Orozco-Ic Mesías, Pan Sudip, Cui Zhong-Hua
Institute of Atomic and Molecular Physics, Jilin University, Changchun 130023, China.
Donostia International Physics Center (DIPC), Donostia, Euskadi 20018, Spain.
Inorg Chem. 2024 Jul 29;63(30):13938-13947. doi: 10.1021/acs.inorgchem.4c01224. Epub 2024 Jul 12.
The recent report of planar tetracoordinate hydrogen (ptH) in InH is very intriguing in planar hypercoordinate chemistry. Our high-level CCSD(T) calculations revealed that the proposed -symmetric ptH InH is a first-order saddle point with an imaginary frequency in the out-of-plane mode of the hydrogen atom. In fact, at the CCSD(T)/aug-cc-pV5Z/aug-cc-pV5Z-PP level, the isomer, with the H atom located 0.70 Å above the In plane, is 0.5 kcal/mol more stable than the isomer. However, given the small perturbation from planarity and essentially barrierless ↔ ↔ transition, the vibrationally averaged structure can still be considered as a planar. Extending our exploration to the InTlH ( = 0-3) systems, we found all these ptH structures, except for InTlH, to be the putative global minimum. The single σ-delocalized interaction between the central hydrogen atom and InTl ligand rings proves pivotal in establishing planarity and aromaticity and conferring substantial stability upon these rule-breaking ptH species.
最近关于InH中平面四配位氢（ptH）的报道在平面超配位化学中非常引人关注。我们的高水平CCSD(T)计算表明，所提出的对称ptH InH是一个一阶鞍点，在氢原子的面外模式中有一个虚频。事实上，在CCSD(T)/aug-cc-pV5Z/aug-cc-pV5Z-PP水平下，H原子位于In平面上方0.70 Å的异构体比异构体稳定0.5 kcal/mol。然而，鉴于与平面性的微小扰动以及基本上无势垒的 ↔ ↔ 转变，振动平均结构仍可被视为平面结构。将我们的探索扩展到InTlH（ = 0 - 3）体系，我们发现除了InTlH之外，所有这些ptH结构都是假定的全局最小值。中心氢原子与InTl配体环之间的单σ离域相互作用被证明对于建立平面性和芳香性以及赋予这些违反规则的ptH物种显著稳定性至关重要。
