Host–guest interactions in the solid state structure of a zinc(II) compound with a protonated diamine and DFT study

Abstract

In this manuscript we report the synthesis of a new zinc(II) compound, [H3NC2H4NH3][ZnLCl]2⋅2DMSO {H2L = N,N’-bis-(3-ethoxysalicylidene)-1,2-diaminoethane}, characterized by elemental and spectral analysis. This structure has been confirmed by single crystal X-ray diffraction study. The complex may be considered as a supramolecular aggregate, where host–guest interactions are operating between two [ClZnL]− moieties acting as hosts and [H3N(CH2)2NH3]2+ species acting as guest. The theoretical DFT study is devoted to evaluate the H-bonding interactions in solid state structure of the complex. The computed MEP at the O4 cavity is significantly more negative than at the chlorido ligand supporting location of the ammonium groups of the di-cation in the solid state. The combination of QTAIM and NCIplot analysis is helpful to disclose the importance of additional CHO contacts in addition to the strong NHO interactions to the inclusion of the [H3N(CH2)2NH3]2+ di-cation in the O4 compartments of two [ClZnL]− moieties.