engleski

Prediction of New Organic Superacids by Computational Chemistry

A superacid is any acid stronger than 100% sulfuric acid (H2SO4). There is an ongoing interest in chemistry for compounds exhibiting extreme acidity, since neutral acids are the most important catalysts in chemical transformations. Usually, the strongest the acid is the better catalyst it makes. Beside that, very stable anions produced after deprotonation of strong acids proved useful in isolation of chemically very important and very reactive cations. Taking all of this into account, a design of novel neutral organic superacids is essential from practical and scientific points of view. We developed a useful strategy in designing exceptionally strong neutral superacids. Such strategy has led to the theoretical prediction of a whole series of molecules possessing superacidic properties. As evidenced by their deprotonation enthalpies in the gas-phase (deltaHacid) or by pKa values in DMSO, they surpass the acidity of sulfuric acid by 30-50 orders of magnitude. Since the selected molecular skeletons are long-known in chemistry and the synthetic pathways of polycyanation are well-documented in the literature it is likely that some of the suggested molecules are prone to chemical synthesis. It is also expected that the conjugate base anions of these superacids possess some useful properties like low nucleophilicity, weak coordinating ability and high solubility in organic solvents, which should make them very useful in everyday chemical applications.

superacidity; aromaticity; substituent effect

nije evidentirano