Della Therese Davis, Suresh Cherumuttathu H
Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, Kerala 695019, India.
Academy of Scientific & Innovative Research (AcSIR), New Delhi 110020, India.
ACS Omega. 2017 Aug 15;2(8):4505-4513. doi: 10.1021/acsomega.7b00664. eCollection 2017 Aug 31.
The dihydrogen-binding ability of polyatomic oxohalo anions ClO, ClO , ClO , ClO , BrO, BrO , BrO , and BrO has been studied at the M06L/6-311++G(d,p) density functional theory and the CCSD(T)/aug-cc-pVTZ//CCSD/aug-cc-pVDZ ab initio theory. The maximum number of dihydrogen adsorbed by the anions ( ) varies from 17 to 24 in the first coordination shell. As the number of H adsorbed varies from 1 to , the oxochloro and oxobromo anions show a wide range for interaction energy ( ), namely, 1.5-45.4 kcal/mol for the former and 1.4-46.0 kcal/mol for the latter. These results indicate that both series of anions show very similar and high affinity to bind with several dihydrogen molecules. Further, an increase in the coordination ability and a decrease in the strength of the dihydrogen interaction are observed with an increase in the number of oxygen atoms in the polyatomic anion. In contrast, the neutral oxohaloacids show negligible interaction with dihydrogen. The anion···H noncovalent interactions along with H···H dihydrogen interactions within the complex are ascertained by locating the bond critical points (bcps) in the quantum theory of atoms in molecules analysis. The electron density at the bcp summed up for all of the anion···H interactions (∑ρ) showed a strong linear relationship with , indicating that the stability of the complex is due to the formation of a large network of noncovalent bonds in the complex. The amount of electron density donated by the anion to the dihydrogen during complex formation is also gauged from the molecular electrostatic potential values at the nuclei ( ) of all of the atoms in the anion. The hydrogen uptake leads to a significant reduction in the negative character of , and the total change in from all of the anion atoms (∑Δ ) is found to be directly proportional to . The polyatomic anions have a very high affinity toward dihydrogen binding, which can be utilized for the development of new hydrogen storage systems.
在M06L/6 - 311++G(d,p)密度泛函理论和CCSD(T)/aug - cc - pVTZ//CCSD/aug - cc - pVDZ从头算理论下，研究了多原子卤氧阴离子ClO、ClO₂、ClO₃、ClO₄、BrO、BrO₂、BrO₃和BrO₄的二氢结合能力。阴离子在第一配位层中吸附的二氢最大数量（ ）在17到24之间变化。随着吸附的H数量从1变化到 ，氯氧和溴氧阴离子显示出相互作用能（ ）的广泛范围，即前者为1.5 - 45.4千卡/摩尔，后者为1.4 - 46.0千卡/摩尔。这些结果表明，这两类阴离子对与几个二氢分子结合都表现出非常相似且高的亲和力。此外，随着多原子阴离子中氧原子数量的增加，观察到配位能力增强，二氢相互作用强度降低。相比之下，中性卤氧酸与二氢的相互作用可忽略不计。通过在分子中的原子量子理论分析中定位键临界点（bcps），确定了配合物内的阴离子···H非共价相互作用以及H···H二氢相互作用。所有阴离子···H相互作用的bcp处的电子密度总和（∑ρ）与 呈现出很强的线性关系，表明配合物的稳定性归因于配合物中形成的大量非共价键网络。在配合物形成过程中阴离子向二氢提供的电子密度量也从阴离子中所有原子的核处的分子静电势值（ ）来衡量。氢的吸收导致 的负性显著降低，并且发现所有阴离子原子的 总变化（∑Δ ）与 成正比。多原子阴离子对二氢结合具有非常高的亲和力，这可用于开发新的储氢系统。
