Structure, bonding, and proton affinities of the H-, Me-, and F-substituted [Fe-III-TAML] complexes and their protonated counterparts were investigated with the topological analysis of the electron density (AIM) and electron localization function (ELF) at the B3LYP/6-31 + G** level. Two protonation sites were found on each of the terminal oxygen atoms. The AIM analysis revealed existence of some weak interactions in the studied molecules. Changes induced by substitution of the tail Me groups by highly electronegative fluorine atoms are rather small (except for C25 atom) and do not fully explain experimentally observed high H+-tolerance of [Fe-III-TAML(R)=(F)] molecule. (C) 2011 Elsevier B.V. All rights reserved.