The (2-hydroxyphenyl)bis(pyrazolyl)methanes: structural characterization of a series of mono-, di-, and trinuclear nickel(II) complexes

A series of mixed functionality biomimetic 'scorpionate' ligands was utilized to synthesize symmetrical nickel(II) dimeric complexes with Ni(mu-O)2NiCl2 moieties. The nuclearity of the isolated Ni(II) complexes was mediated by the degree of steric hindrance on the pyrazole rings. The absence of steric bulk also allows the coordination of two ligands to each metal atom in a tridentate manner. Furthermore, the magnetic interactions between the two Ni(II) centers of the compounds exhibited octahedral and tetrahedral geometries, respectively.