Proton transfer or hemibonding? The structure and stability of radical cation clusters.
Proton transfer or hemibonding? The structure and stability of radical cation clusters.
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DOI：
10.1039/c3cp52922c
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发表时间：
2013-09
期刊：
影响因子：
--
通讯作者：
Hainam Do;N. Besley
中科院分区：
文献类型：
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作者：
Hainam Do;N. Besley
本文采用盆跳跃搜索算法结合二阶Møller-Plesset微扰理论计算了自由基阳离子团簇（NH3）n stec（+），（H2O）n stec（+），（HF）n stec（+），（PH 3）n stec（+），（H2S）n stec（+）和（HCl）n stec（+）的最低能量结构，其中n = 2-4.最稳定的结构的能量随后使用耦合簇理论结合aug-cc-pVTZ基组进行评估。这些阳离子簇可以采用两种不同的结构类型，其中一些簇显示出不寻常的键合类型，通常被称为半键合，而其他簇经历质子转移以产生离子和自由基。结果表明，（NH 3）nstec（+）、（H2 O）nstec（+）和（HF）nstec（+）簇合物更倾向于质子转移结构，而（PH 3）nstec（+）、（H2 S）nstec（+）和（HCl）nstec（+）簇合物更倾向于半键结构.这些趋势可以归因于分子和分子阳离子分别作为布朗斯台德碱和酸的相对强度，以及离子-自由基簇中离子和自由基之间的相互作用强度。
The basin hopping search algorithm in conjunction with second-order Møller-Plesset perturbation theory is used to determine the lowest energy structures of the radical cation clusters (NH3)n˙(+), (H2O)n˙(+), (HF)n˙(+), (PH3)n˙(+), (H2S)n˙(+) and (HCl)n˙(+), where n = 2-4. The energies of the most stable structures are subsequently evaluated using coupled cluster theory in conjunction with the aug-cc-pVTZ basis set. These cationic clusters can adopt two distinct structural types, with some clusters showing an unusual type of bonding, often referred to as hemibonding, while other clusters undergo proton transfer to give an ion and radical. It is found that proton transfer based structures are preferred by the (NH3)n˙(+), (H2O)n˙(+) and (HF)n˙(+) clusters while hemibonded structures are favoured by (PH3)n˙(+), (H2S)n˙(+) and (HCl)n˙(+). These trends can be attributed to the relative strengths of the molecules and molecular cations as Brønsted bases and acids, respectively, and the strength of the interaction between the ion and radical in the ion-radical clusters.