Theoretical investigation of the H(CHB11 X11 ) (X=H, F, Cl, CN), H(CHB11 Xn Y11-n ) (X,Y=F, Cl; n=1,5), and dimeric (H(CHB11 X11 ))2 (X=F, Cl) carborane superacids performed at the B3LYP/6-311++G(d,p) theory level revealed the similarity of their equilibrium structures and the possibility of nearly barrierless hydrogen atom migration among the substituents attached to one side of the icosahedral CB11 cage. The vertical electron detachment energies predicted at the OVGF/6-311++G(3df,2pd) theory level for the conjugate bases (CHB11 X11 )- were found to span the 5.82-9.00 ev range. The acid strengths (manifested by the Gibbs free deprotonation energies spanning the 213-266 kcal/mol range) predicted for the icosahedral H(CHB11 X11 ) carborane systems confirm their superacidic properties which might be increased even further by the attachment of the second carborane H(CHB11 X11 ) unit that leads to a dimeric structure mimicking a part of an experimentally observed H-bridged polymeric chain. The Gibbs free deprotonation energy of the dimeric (H(CHB11 Cl11 ))2 acid was predicted to be smaller by 17 kcal/mol than that of the corresponding monomeric H(CHB11 Cl11 ) acid.

中文翻译：

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二十面体碳硼烷超强酸及其共轭碱基，包含H，F，Cl和CN取代基：单体和二聚体笼的理论研究。

H（CHB11 X11）（X = H，F，Cl，CN），H（CHB11 Xn Y11-n）（X，Y = F，Cl; n = 1,5）和二聚体（H（在B3LYP / 6-311 ++ G（d，p）理论水平上进行的CHB11 X11））2（X = F，Cl）碳硼烷超强酸显示出其平衡结构的相似性以及氢原子之间几乎无障碍迁移的可能性取代基附着在二十面体CB11笼的一侧。发现在OVGF / 6-311 ++ G（3df，2pd）理论水平上对共轭碱（CHB11 X11）-预测的垂直电子脱离能在5.82-9.00 ev范围内。二十面体H（CHB11 X11）碳硼烷体系的预测酸强度（由213-266 kcal / mol范围内的吉布斯自由去质子能体现）证实了它们的超酸性，这可能会由于第二碳硼烷H的附着而进一步提高。 （CHB11 X11）单元，该单元可模仿模拟观察到的H桥连聚合物链的一部分的二聚体结构。预测二聚（H（CHB11 Cl11））2酸的吉布斯自由去质子能比相应的单体H（CHB11 Cl11）酸的吉布斯自由去质子能小17 kcal / mol。