Features of Protonation of the Simplest Weakly Basic Molecules, SO2, CO, N2O, CO2, and Others by Solid Carborane Superacids

• Published in: Angewandte Chemie International Edition 2018-04, Vol.57 (17), p.4516-4520
• Main Authors: Stoyanov, Evgenii S., Stoyanova, Irina V.
• Format: Article
• Language: English
• Subjects: Acids; Basicity; Bonding strength; Carbon dioxide; Carborane; carborane superacids; Chemical bonds; Hydrogen; Nitrous oxide; Partial pressure; Protonation; Sulfur dioxide
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201704645

An experimental study on protonation of simple weakly basic molecules (L) by the strongest solid superacid, H(CHB11F11), showed that basicity of SO2 is high enough (during attachment to the acidic H atoms at partial pressure of 1 atm) to break the bridged H‐bonds of the polymeric acid and to form a mixture of solid mono‐ LH+⋅⋅⋅An−, and disolvates, L−H+−L. With a decrease in the basicity of L=CO (via C), N2O, and CO (via O), only proton monosolvates are formed, which approach L−H+−An− species with convergence of the strengths of bridged H‐bonds. The molecules with the weakest basicity, such as CO2 and weaker, when attached to the proton, cannot break the bridged H‐bond of the polymeric superacid, and the interaction stops at stage of physical adsorption. It is shown here that under the conditions of acid monomerization, it is possible to protonate such weak bases as CO2, N2, and Xe. Non‐protonable molecules: Weakly basic molecules (L=SO2, CO, N2O, CO2 and others) can be protonated by the strongest solid superacid H(CHB11F11) depending on conditions.