132802-38-1Relevant academic research and scientific papers
Activation of α-bromo ketones by comlexation with hard and soft lewis acids. A combined x-ray and nmr study
Laube, Thomas,Weidenhaupt, André,Hunziker, Richard
, p. 2561 - 2567 (2007/10/02)
α-Halo ketones have two heteroatoms with lone pairs where a Lewis acid can be bound, depending on the softness or hardness of the Lewis acid (HSAB principle). The crystal structures of the complexes 2-SbCl5, 3-SbCl5, 8-AgSbF6, and (2)2·AgSbF6 have determined in order to analyze the structural and electronic in the bromo molecules upon complexation and the different binding properties of a hard (SbCl5) and a soft Lewis acid (Ag4+), The monodentate Lewis acid SbCl5 binds to the oxygen atom, whereas the silver ion is coordinated to the O and the Br atom of a bromo ketone in a chelate-like manner and to the π-systems of phenyl rings. 1H and 13C NMR measurements of the complexes and of the pure bromo ketones in solution support and complete the results of the X-ray structure determinations; SbCl5 activates the C=0 bond by raising the contribution of the C+-O- resonance formula, whereas Ag+ activates preferentially the C-Br bond by raising the contribution of the C+Br- resonance formula. The observations are in agreement with reactivity from the literature.
