Synthesis, structure and reactivity study of magnesium amidinato complexes derived from carbodiimides and N,N′-bis(2,6-diisopropylphenyl)-1,4-diaza-butadiene ligandsElectronic supplementary information (ESI) available. CCDC 1019669-1019675. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4dt03074e

We report an amidinato ligand-supported series of magnesium complexes obtained from the insertion of a magnesium-carbon bond into a carbon-nitrogen double bond of different carbodiimides and α-diimine ligands. The magnesium complexes [Mg(CH 2 Ph){CyN&z.dbd;C(CH 2 Ph)NCy}] 2 ( 1 ), [Mg(CH 2 Ph){ i PrN&z.dbd;C(CH 2 Ph)N i Pr}] 2 ( 2 ) and the homoleptic [Mg{ t BuN&z.dbd;C(CH 2 Ph)N t Bu} 2 ] ( 3 ) (Cy = cyclohexyl, i Pr = isopropyl, t Bu = tert -butyl) were prepared by the reaction of dibenzyl magnesium [Mg(CH 2 Ph) 2 (Et 2 O) 2 ] with the respective carbodiimides either in 1 : 1 or 1 : 2 molar ratio in toluene. The analogous reaction of [Mg(CH 2 Ph) 2 (Et 2 O) 2 ] with the N , N ′-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene (Dipp 2 DAD) ligand afforded the corresponding homoleptic magnesium complex [Mg{DippN&z.dbd;C(CH 2 Ph)CH 2 NDipp} 2 ] ( 4 ) (Dipp = 2,6 diisopropylphenyl) in good yield. The solid-state structures of magnesium complexes 1-4 were confirmed by single-crystal X-ray diffraction analysis. It was observed that in each case, a magnesium-carbon bond was inserted into the carbon-nitrogen double bond of either carbodiimides or Dipp 2 DAD resulting in a monoanionic amido-imino ligand. In a further reaction between 1 and N -aryliminopyrrolyl ligand 2-(2,6- i Pr 2 C 6 H 3 N&z.dbd;CH)C 4 H 3 NH (ImpDipp-H) in 1 : 2 molar ratio, a new magnesium complex [Mg(ImpDipp) 2 {CyN&z.dbd;C(CH 2 Ph)NHCy}] ( 5 ), with one amidinato and two aryliminopyrrolyl ligands in the coordination sphere, was obtained in good yield. In contrast, the homoleptic magnesium complex 4 reacted with one equivalent of N -aryliminopyrrolyl ligand (ImpDipp-H) to produce another mixed ligated magnesium complex [Mg{DippN&z.dbd;C(CH 2 Ph)CH 2 NDipp}(ImpDipp)] ( 6 ), with a benzylated DAD ligand and aryliminopyrrolyl ligands in the coordination sphere. Further reaction of complex 4 with benzyl alcohol (PhCH 2 OH) afforded the third mixed ligated magnesium complex [Mg{DippN&z.dbd;C(CH 2 Ph)CH 2 NDipp}(OCH 2 Ph) 2 ] ( 7 ) in very good yield. The magnesium complexes 5-7 were characterised using standard analytical/spectroscopic techniques and their solid-state structures were established by single-crystal X-ray diffraction analysis. A series of amidinato ligand supported magnesium complexes derived from the insertion of Mg-C bond into the carbon-nitrogen double bond of different carbodiimides (RN&z.dbd;C&z.dbd;NR) (R = Cy, i Pr, t Bu) and Dipp 2 DAD ligand.