A new strategy to generate super and hyper acids with simple organic molecules exploiting σ-hole interaction

Abstract

Super and hyper acidity can be achieved using σ-hole non-covalent interactions with simple organic systems. The σ-hole interaction can stabilize the conjugate base of acids to such an extent that cyclopentadiene yields a ΔH_acid of 256 kcal mol⁻¹, which is ∼100 kcal mol⁻¹ lower than the reported results. The hyper acidic value of 209.0 kcal mol⁻¹ of organic acids has been achieved without electron-withdrawing substituents rather exploiting only σ-hole interaction. Remarkably, the 1st and 2nd acidity values (∼229 kcal mol⁻¹) of comparable strength in the hyperacid range have been observed for the first time using DFT computations. The simple organic acids were predicted to reach the pK_a values in the range of −7.3 to −7.8 in DMSO, which is remarkably lower than previous reports. These stable anions can be a potential candidate for application as an effective electrolyte in lithium-ion batteries.