The aromatic character of the transition state structures (TSs) involved in pseudocyclic reactions of fluorinated compounds

[Display omitted] •Aromaticity was measured by using the most popular aromatic criterion•NICS, HOMA and FLU indices are completely unsuccessful to provide the best results•LOL, ELF, QTAIM, PDI indices based electron density were wonderfully proven the non-aromatic character of studied TSs•At least two interactive atoms are not bounds at the TSs structures through a not continuous process•The TSs structures do not have π electron delocalization in the six-membered ring and then not aromatic The definition of aromaticity and their measure were taken considerable attention in the past years. Generally, the aromaticity was frequently described as an electron delocalization pattern within a cyclic structure, characterized by unusual stability. More significantly, with the progress of the accuracy and versatility of ab initio and density functional theory (DFT) computations, it is very conceivable to evaluate the aromaticity of so-called pericyclic transition state structures (TSs) involved in some classical reactions of fluorinated compounds. In this study, several successful models were effectively explored, geometries and energy barriers have not been exactly provided convincing results, and surprisingly NICS and FLU index do not present precise estimation, as long as the HOMA index is effective simply for some cases. Fascinatingly, Localized orbital locator (LOL), ELF, QTAIM of Laplacian of the electron density, ∇2ρcp and PDI index are impeccably provided satisfy outcomes through demonstrating that the studied TSs are not-aromatic, due to lack of π electron delocalization.