Nucleophilic properties of the positively charged metal center in the solid state structure of Palladium(II)-Terpyridine complex

Weak intermolecular noncovalent interactions in the solid palladium(II)-terpyridine complex [4'-(4-methoxyphenyl)-2,2':6′,2″-terpyridine]chloridopalladium(II) chloride were studied by XRD method accompanied with appropriate DFT calculations. The complex in the crystal lattice exhibits a double columnar planar structure. Inside the columns, the complex cations are linked by stacking rather than by hydrogen bonding. DFT calculations and topological analysis of the electron density distribution within the formalism of Bader's theory (QTAIM method) were performed for the terpyridine complex model cluster. The calculation data indicate that the columns are interconnected by π-hole···[dz2-Pd] and π-hole···lp(Cl) interactions. Estimated strength of these noncovalent contacts varies in range 0.5–1.6 kcal/mol. Metal centers are involved in the stacking via dz2–π noncovalent bonds, which proved to be more preferable than the Pd⋯Pd metallophilic interactions. The electrostatic surface potential calculations demonstrated dz2nucleophilic properties of the cationic metal center.