Martín-Fernández Carlos, Montero-Campillo M Merced, Alkorta Ibon, Elguero José
Instituto de Química Médica, CSIC , Juan de la Cierva, 3, 28006 Madrid, Spain.
Department of Chemistry, KU Leuven , Celestijnenlaan, 200F, 3001 Leuven, Belgium.
J Phys Chem A. 2017 Oct 5;121(39):7424-7431. doi: 10.1021/acs.jpca.7b07886. Epub 2017 Sep 20.
The proton affinity (PA) on the oxygen atom in silanol and siloxane derivatives is enhanced by the formation of tetrel bonds with small Lewis bases [B···RSiOH, B···RSiOSiR, B···RSiOSiR···B; B = HO, CO, NH, HCN, HS; R = H, Me], as shown by MP2/jul-cc-pVTZ calculations. The complexed systems become more basic than ether and other carbon-related compounds, and even more basic than pyridine in some specific cases, reaching values up to 959.4 kJ/mol (HN···HSiOSiH···NH complex). Changes on PAs are directly related to very large binding energies for the protonated species. Topological methods and the natural bond orbital scheme are used to rationalize the observed trends. The PA enhancement should be taken into account when dealing with silanols and siloxanes in different environments.
如MP2/jul-cc-pVTZ计算所示，硅醇和硅氧烷衍生物中氧原子上的质子亲和力（PA）通过与小的路易斯碱形成四元键[B···RSiOH、B···RSiOSiR、B···RSiOSiR···B；B = HO、CO、NH、HCN、HS；R = H、Me]而增强。在某些特定情况下，络合体系比醚和其他碳相关化合物碱性更强，甚至比吡啶碱性更强，质子亲和力高达959.4 kJ/mol（HN···HSiOSiH···NH络合物）。质子亲和力的变化与质子化物种的非常大的结合能直接相关。拓扑方法和自然键轨道方案用于解释观察到的趋势。在处理不同环境中的硅醇和硅氧烷时，应考虑质子亲和力的增强。
