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Square-Planar Diacetatopalladium Complexes with <i>trans</i>-Configured Secondary Amine Ligands that Avoid Orthometalation: Ligand Synthesis, Coordination, Molecular Structure and Catalytic Potential for Suzuki Cross-Coupling Reactions
Auteur(s)
Date Issued
2007
Journal
European Journal of Inorganic Chemistry, Wiley, 2007/32//5045-5051
Abstract
The <i>trans</i>-configured square-planar palladium complexes [Pd(OAc)<sub>2</sub> (LN<i>t</i>Bu)<sub>2</sub>] (<b>1</b>), [Pd(OAc)<sub>2</sub> (η<sup>2</sup>-LN∩N<i>t</i>Bu)] (<b>2</b>), [Pd(OAc)<sub>2</sub> (LNPh)<sub>2</sub>] (<b>3</b>), and [Pd(OAc)<sub>2</sub> (η<sup>2</sup>-LN∩NPh)] (<b>4</b>), have been synthesized by treating palladium acetate with the amines NH<i>t</i>BuCH<sub>2</sub>-2,4,6-Me<sub>3</sub>C<sub>6</sub>H<sub>2</sub> (LN<i>t</i>Bu) or NHPhCH<sub>2</sub>-2,4,6-Me<sub>3</sub>C<sub>6</sub>H<sub>2</sub> (LNPh) or with the diamines NH<i>t</i>BuCH<sub>2</sub>-2,4,6-Me<sub>3</sub>C<sub>6</sub>H-CH<sub>2</sub>-2,4,6-Me<sub>3</sub>C<sub>6</sub>H-CH<sub>2</sub>-NH<i>t</i>Bu (LN∩N<i>t</i>Bu) or NHPh-CH<sub>2</sub>-2,4,6-Me<sub>3</sub>C<sub>6</sub>H-CH<sub>2</sub>-2,4,6-Me<sub>3</sub>C<sub>6</sub>H-CH<sub>2</sub>-NHPh (LN∩NPh). The single-crystal X-ray structure analysis of complexes <b>1-3</b> confirms a trans arrangement of the two acetato groups and of the two nitrogen atoms. Orthometalation leading to palladacycles is impossible in all cases as the <i>ortho</i> positions in the benzylic rings are blocked by methyl substituents. All complexes are found to catalyze Suzuki cross-coupling reactions of deactivated and even sterically hindered arene substrates.
Publication type
journal article
