Syntheses and Structures of Magnesium Complexes with Reduced α-Diimine Ligands

The reduction of neutral α-diimine ligands bearing different substituents on the N-aryl rings by different amounts of potassium metal and subsequent reaction with anhydrous MgCl2 in THF afforded a series of magnesium compounds, [(LiPr)2–Mg­(THF)2]·THF (2), [(LMes)2–Mg­(THF)3] (3), [(LiPr)−2Mg]·THF (4), [(LMes)−2Mg] (5), and [(LMes)2–2Mg­(η6:η6-K­(THF)2)]­[K­(THF)6]·(THF)2 (6) (LiPr = [(2,6-iPr2C6H3)­NC­(Me)]2), LMes = [(2,4,6-Me3C6H2)­NC­(Me)]2). Complexes 2–6 have been characterized by single-crystal X-ray diffraction, elemental analysis, NMR spectroscopy, and EPR studies (for 4 and 5). The noninnocent α-diimine ligands exist as the dianionic form in compounds 2, 3, and 6 and as a monoanion in 4 and 5. Effects of the ligand substituents and the amount of the reducing agent on the structure of the product have been discussed.