Dinuclear palladium complexes of pyrazolato-bridged imidazolium- and NHC-ligands: Synthesis and characterization

• Two novel dinuclear Pd complexes with a multidentate ligands are presented.
• Different reaction conditions selectively yield different coordination modes.
• Single crystal X-ray diffraction studies unequivocally proved the structures.

The reactions of dinuclear palladium precursors with the pyrazolato-bridged bis(imidazolium) salt 3,5-bis(methylimidazolium-1-ylmethyl]-1H-pyrazole bis(hexafluorophosphate) at different conditions are investigated to further explore the scope of this ligand class towards multinuclear complexes. Depending on the reaction conditions, in dichloromethane a dinuclear twofold μ-pyrazolato bridged bis(imidazolium) complex has been selectively synthesized, whereas the corresponding double μ-pyrazolato bridged bis(NHC) complex was obtained when using acetonitrile as solvent. Both complexes were characterized by NMR, elemental analysis and single crystal X-ray diffraction.

The solvent makes the difference: depending on the reaction conditions, in dichloromethane a dinuclear twofold μ-pyrazolato bridged bis(imidazolium) complex has been selectively synthesized, whereas the corresponding double μ-pyrazolato bridged bis(NHC) complex was obtained when using acetonitrile as solvent.Figure optionsDownload as PowerPoint slide