Magnesium, zinc and aluminium complexes supported by tripodal diaminebis(aryloxido) ligands: synthesis, solid state and solution structure

The reactions of the diaminebis(aryloxido) ligand precursors [Me2NCH2CH2N(CH2-4-R-C6H3OH)(2)] [R = C(CH3)(2)CH2C(CH3)(3), H2L1.; R = CH3, H2L2] with (MgBu2)-Bu-n, ZnEt2 and AlEt3 create complexes of general formula [M-2(mu-L-kappa O-4,N,N,O)(2)] (M = Mg, 1a for L-1 and 1b for L-2.; M = Zn, 2a for L-1 and 2b for L-2) and [Al-2(mu-L-kappa O-3,N,N,O)(2)Et-2] (3 for L-1) in good yields. Compounds 1a-3 were characterized by NMR spectroscopy and ESI-MS experiments. The definitive molecular structure of 1b center dot CH2Cl2, 2a center dot H2O, 2b center dot CH2Cl2 and 3 was provided by a single-crystal analysis and revealed their dimeric nature with an M2O2 planar core. The L-1 and L-2 ligands coordinate as the dianions in a tetradentate/bridging manner in 1b, 2a, 2b and in a tridentate/ bridging mode in 3. The NMR spectra showed that the solid state of these compounds is essentially retained in solution.