The First Oxidation of a Cr₂⁴⁺ Paddlewheel Complex to an Isostructural Stable Product

The first cation containing a Cr2 core surrounded by a paddlewheel arrangement of four bridging ligands has been prepared and characterized. The bridging ligands are the guanidinate anions [(PhN)2CN(CH2)4]-. In the neutral Cr24+ compound the average Cr−Cr distance is 1.904[1] Å, and in the cation (which is accompanied by a PF6- anion) the Cr−Cr distance is 1.9249(9) Å. The cation has one unpaired electron, but the EPR spectrum is devoid of hyperfine structure and has g ≈ 2.00. We proposed that the oxidation is essentially delocalized on the ligands.