Synthesis and structural characterization of bis(salicylaldiminato) magnesium complexes of varying aggregation and coordination state

Geoffrey T. Quinque, Elizabethtown College
Allen G. Oliver, University of Notre Dame
Jeffrey A. Rood, Elizabethtown College


A series of salicylaldiminato ligands [C H N=CHC H OH ( L), 2,6-iPrC H N=CHC H OH ( L), and 2,6-iPrC H N=CH-3,5-tBu C H OH ( L)] were treated with Bu Mg in the presence of the appropriate solvent system to yield the crystalline compounds [( L Mg )·thf] (1), [( L Mg·thf)] (2), and [ L Mg] (3). The products were characterized by H and C 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. A series of bis(salicylaldiminato)magnesium complexes have been synthesized and characterized in the solid state. Substitution of the ligand backbone was found to influence both the aggregation and the magnesium coordination state in these complexes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. 6 5 6 4 6 3 6 4 6 3 2 6 2 2 6 3 2 2 1 2 3 1 2 3 1 13