Marcin Czapla

Strength of the Lewis-Brønsted Superacids Containing In, Sn, and Sb and the Electron Binding Energies of Their Corresponding Superhalogen Anions.

The HInnF3n+1, HSnnF4n+1, and HSbnF5n+1 (n = 1-3) compounds and their corresponding InnF3n+1(-), SnnF4n+1(-), SbnF5n+1(-) (n = 1-3) anions were investigated by employing the B3LYP, QCISD, and OVGF quantum chemistry methods and the LANL2DZ/6-311++G(d,p) basis sets. Our calculations revealed very strong acidity of all examined neutral compounds and large electronic stabilities (in the range 9.9-13.3 eV) of their corresponding anions. The gas phase acidities (manifested by small Gibbs free energies of deprotonation, ΔGacid) predicted for the HSn3F13 and HSb3F16 (ΔGacid of 243.5 and 230.3 kcal/mol at T = 298.15 K, respectively) suggest that these systems should actually act as even stronger acids than the F(SO3)4H and HSbF6 compounds (recognized thus far as the strongest superacids).

The saturation of the gas phase acidity of nHF/AlF3 and nHF/GeF4 (n = 1–6) superacids caused by increasing the number of surrounding HF molecules

The acidic strength of selected Bronsted/Lewis superacids is evaluated on the basis of theoretical calculations carried out at the QCISD/6-311++G(d,p) level. The energies and Gibbs free energies of deprotonation processes for nHF/AlF3 and nHF/GeF4 (n = 1–6) are found to depend on the number (n) of hydrogen fluoride molecules (playing a Bronsted acid role) surrounding the AlF3 and GeF4 Lewis acids. The successive attachment of HF molecules to either AlF3 or GeF4 gradually increases the acidity strength of the resulting superacid, which leads to the saturation achieved for 5–6 HF molecules interacting with either one of these Lewis acids. The importance of the microsolvation of the corresponding anionic species as well as the necessity of considering larger (more structurally complex) building blocks of superacids while predicting their acidity is indicated and discussed.

Formation of Enormously Strongly Bound Anionic Clusters Predicted in Binary Superacids

The possible formation of the (AlF4(HF) n)- ( n = 1-8 and 12), (AsF6(HF) n)-, and (SbF6(HF) n)- ( n = 1-6 and 12) anionic clusters of a superhalogen nature is predicted in the solutions of binary HF/AlF3, HF/AsF5, and HF/SbF5 Lewis-Brønsted superacids on the basis of ab initio calculations. Our results show that all systems investigated represent extremely strongly bound anions characterized by vertical electron detachment energies (VDEs) that significantly exceed 10 eV. The VDE values estimated for the (AlF4(HF)12)-, (AsF6(HF)12)-, and (SbF6(HF)12)- systems are predicted to be 13.96, 14.03, and 14.03 eV, respectively, and are the largest vertical electron detachment energies reported in the literature thus far.