Trinuclear Diamagnetic Nickel(II) Complexes with Bridging 3-Arylpyrazolato Ligands.

Orange-red trinuclear nickel(II) complexes are obtained by reacting Ni(ClO₄)₂(H₂O)₆ with 3(5)-arylpyrazoles in the presence of a base. Herein, the diamagnetic nickel centers are coordinated in a square-pyramidal manner by four pyrazolato ligands, each of which bridges two nickel sites. The structurally unique complexes were investigated by NMR, IR, fluorescence, and X-ray spectroscopy. All seven compounds described here were structurally elucidated by single-crystal X-ray diffraction. With 3(5)-ferrocenylpyrazole as the substrate, a nonametallic system that possesses six redox-active ferrocenyl moieties was obtained. [ABSTRACT FROM AUTHOR]