Redox potential parameterization in coordination compounds with polydentate scorpionate and benzene ligands

The Lever redox potential parameterization model is extended to half-sandwich type complexes bearing polydentate boron-based or carbon-based scorpionate-type or π-aromatic (benzene or p-cymene) ligands, allowing to estimate the electrochemical EL ligand parameter of a diversity of such polytopal ligands which, thus, are ordered according to their electron-donor character and compared with other ligands. Partial EL values assigned to each metal ligated arm (2-electron-donor) of the scorpionate ligand (i.e., pyrazolyl, indazolyl or carboxylate groups) and to each unsaturated CC moiety of π-benzene (or π-p-cymene) are also proposed. The studied scorpionate ligands comprise the following basic ones and derivatives: tris(pyrazol-1-yl or indazol-1-yl)borate, tris(pyrazol-1-yl)methane and bis(pyrazol-1-yl)acetic acid.