Synthesis and Structural Characterization of Bis(salicylaldiminato)magnesium Complexes of Varying Aggregation and Coordination State

Abstract

AbstractA series of salicylaldiminato ligands [C6H5N=CHC6H4OH (1L), 2,6‐iPrC6H3N=CHC6H4OH (2L), and 2,6‐iPrC6H3N=CH‐3,5‐tBu2C6H2OH (3L)] were treated with Bu2Mg in the presence of the appropriate solvent system to yield the crystalline compounds [(1L6Mg3)·thf] (1), [(2L2Mg·thf)] (2), and [3L2Mg] (3). The products were characterized by 1H and 13C NMR spectroscopy and single‐crystal X‐ray diffraction. X‐ray crystallographic analysis revealed that 1 adopts a unique trimeric aggregation state consisting of six‐coordinate magnesium centers. Substitution of the ligand backbone resulted in the formation of the monomeric species 2 and 3. X‐ray crystallographic analyses revealed 2 as a five‐coordinate, distorted square‐pyramidal magnesium complex and 3 as a four‐coordinate, distorted tetrahedral species. Inspection of the metrical parameters in 1–3 indicates a decrease in the Mg–O and Mg–N bond lengths and an increase in the N–Mg–O bite angle with a decreasing coordination number at magnesium.