Intermolecular hydrogen bonding H···Cl^- in the solid palladium(II)-diaminocarbene complexes

Weak intermolecular non-covalent H···Cl⁻ interactions in the solid chelated palladium(II)-diaminocarbene complex cis-[PdCl(CNXyl){C(NHXyl)=NHC₆H₂Me₂ NH₂}]Cl (3; Xyl=2,6-Me₂C₆H₃) were studied by XRD followed by appropriate DFT calculations. The N–H···Cl contacts for both NH groups in the carbene moiety are different (N1–H···Cl2 3.5258(19), N2–H···Cl2 3.0797(17) Å). The DFT calculations and topological analysis of the electron density distribution within the formalism of Bader’s theory (QTAIM method) were performed for a model cluster of the carbene complex 3. The theoretical data confirmed that the strength of intermolecular HB H···Cl⁻ is different for two NH-protons of the carbene fragment. The influence of crystal packing effects on the formation of hydrogen bonds in the cluster of 3 is noticeable.