In situ synthesis of mononuclear copper(II) complexes of the new tridentate ligand bis[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]amine

Two mononuclear copper complexes, {bis[(3,5-dimethyl-1H-pyrazol-1-yl-κN²)methyl]amine-κN}(3,5-dimethyl-1H-pyrazole-κN²)(perchlorato-κO)copper(II) perchlorate, [Cu(ClO₄)(C₅H₈N₂)(C₁₂H₁₉N₅)]ClO₄, (I), and {bis[(3,5-dimethyl-1H-pyrazol-1-yl-κN²)methyl]amine-κN}bis(3,5-dimethyl-1H-pyrazole-κN²)copper(II) bis(hexafluoridophosphate), [Cu(C₅H₈N₂)₂(C₁₂H₁₉N₅)](PF₆)₂, (II), have been synthesized by the reactions of different copper salts with the tripodal ligand tris[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]amine (TDPA) in acetone–water solutions at room temperature. Single-crystal X-ray diffraction analysis revealed that they contain the new tridentate ligand bis[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]amine (BDPA), which cannot be obtained by normal organic reactions and has thus been captured in the solid state by in situ synthesis. The coordination of the Cu^II ion is distorted square pyramidal in (I) and distorted trigonal bipyramidal in (II). The new in situ generated tridentate BDPA ligand can act as a meridional or facial ligand during the process of coordination. The crystal structures of these two compounds are stabilized by classical hydrogen bonding as well as intricate nonclassical hydrogen-bond interactions.