Spectroscopic and electrochemical studies on dinuclear mixed Ni(II)-chelates

Summary Solvatochromic dinuclear mixed Ni(II)-complexes with one 1,2-diacetyl-1,2-dibenzoyl-ethanate (dadb^2–) and two tetramethylethylenediamine (tmen) ligands have been prepared and characterized. The tetraphenylborate is orange with molecules in bis-square-planar configuration and the nitrate is green with molecules in a bis-octahedral form. They have been investigated by UV, Vis, IR, and Far-IR spectroscopy as well as by electrochemical and magnetochemical methods. In strong donor solvents the nitrate ligands are replaced by solvent molecules. In weak donor solvents the anion-dependent equilibrium between the bis-planar, the bis-octahedral and an intermediate planar-octahedral form was investigated.Dedicated to Professor Dr. Edwin Hengge on occasion of his 60th birthday