Interplay between different metal–ligand binding modes in tin(II) complexes with pyridine

Abstract

In this work, the π-complexation interaction between simple tin(II) molecules SnX2 (X = H, F, Cl, Br, I) and the π-cloud of pyridine (py) in a series of their model complexes SnX2·py was characterized using a variety of quantum chemical methods. Moreover, the coexistence of this interaction and the well-known σ-complexation interaction between the lone pair on the N atom of py and another SnX2 molecule was studied in the corresponding series of model complexes SnX2·py·SnX2. The interplay between the two metal–ligand binding modes was established in terms of structural changes, interaction energies, interaction energy components and topological electron density parameters. The interaction between SnX2 and py in their SnX2·py π-complexes is weak and its strength is further diminished by the σ-complexation of another SnX2 molecule, forming the SnX2·py·SnX2 complexes. The weakening is in fact mutual yet the strength of the σ-complexation interaction is reduced only marginally.