An Atoms-in-Molecules Theory Interpretation for the Structure of Di- n -Butyltin(IV) Derivative of Glycylvaline

The topological and energetic properties of the electron density distribution ρ (r⃗) for the tin–ligand interaction in n -Bu 2 SnL, the geometric configuration of which was optimized at B3LYP/6-31G(d,p)/LANL2DZ(Sn) level of theory, have been theoretically calculated at the bonds around the central Sn atom in terms of atoms-in-molecules (AIM) theory using AIMAll (Version 16.01.09, standard). In n -Bu 2 SnL, the formation of a (3, − 1) critical point in the internuclear region between tin atom and bonded/coordinated atoms provided an evidence of a bonding interatomic interaction, and calculated bond path angles indicated a distorted trigonal bipyramidal geometry. The calculated topological and energetic parameters suggested a weak closed-shell interaction in all the bonded/coordinated bonds to Sn atom. This interaction possessed covalent character in Sn–N peptide , Sn–C α and Sn–C α′ , whereas an electrostatic interaction was observed in Sn–N amino and Sn–O carboxyl bonds. The calculated atomic charges suggested negatively charged centers around the central Sn atom.