Oxidation State Assignments in the Organoplatinum One‐Electron Redox Series [(N ^ N)PtMes 2 ] n , n = +,0, –,2‐

The neutral complexes [(N ^ N)PtMes 2 ], N ^ N = bis(1‐methyl‐2‐imidazolyl)ketone (bik) or N,N'‐disubstituted 1,2‐bis‐iminoacenaphthenes (R‐BIAN), Mes = mesityl, were obtained and characterized as Pt II species with planar N 2 PtC 2 configuration and charge transfer transitions in the visible. Reversible one‐electron reduction produces radical anion complexes with the spin predominantly localized in the N ^ N ligand, according to EPR, UV/Vis‐IR spectroelectrochemistry, DFT and TD‐DFT studies. Reversible one‐electron oxidation was also possible, attributed to the steric and electronic influence from the mesityl ligands. The EPR silent cation [(bik)PtMes 2 ] + was characterized by UV/Vis‐NIR spectroscopy and TD‐DFT calculations as a system with spin density contributions from Pt (31 %) and two mesityl groups (69 %).