Amino Imidazolin‐2‐imine Ligands in Magnesium Complexes: Approaches Towards Low‐Valent Mg(I) Species

Amino imidazoline‐2‐imines (AmIm) are a new class of chelating, monoanionic N,N' ‐donor ligands stronger than the analogous β ‐diketiminate ligands and give rise to five‐membered metallacycles. The coordination chemistry of the monoanionic ligands 1,2‐NHC=N−C 6 H 4 −NDipp − (i), cis ‐1,2‐NHC=N−CMe=CMe−NDipp − (ii) was towards magnesium was investigated with the focus on the stabilization of low‐valent magnesium(I) species, NHC= cyclo ‐C(N i Pr 2 CMe) 2 , Dipp=2,6‐ i PrC 6 H 3 . Both ligand systems (i) and (ii) form heteroleptic magnesium iodide species with were subjected to reduction. The complex [Mg(1,2‐NHC=N−C 6 H 4 −NDipp)] 2 was found to be insoluble, which prevented further purification. In contrast, the yield of the analogous complex [Mg( cis ‐1,2‐NHC=N−CMe=CMe−NDipp)] 2 was very low. As a significant side product the homoleptic complex [Mg( cis ‐1,2‐NHC=N−CMe=CMe−NDipp) 2 ] was identified.