Symmetrical Palladium (II) N,N,O,O-Schiff Base Complex: Efficient Catalyst for Heck and Suzuki Reactions

Abstract

Palladium is arguably the most versatile and most widely applied catalytic metal in the field of fine chemicals due to its high selectivity and activity. Palladium catalyst offers an abundance of possibilities of carbon-carbon bond formation in organic synthesis. In this research, three different Schiff base ligands have been prepared by condensation reaction between appropriate aldehyde or ketone with amine namely 2,2-dimethyl-1,3-propanediamine in the molar ratio of 2:1. The corresponding palladium (II) Schiff base complexes were prepared through the reaction between the Schiff base ligand with palladium (II) acetate in a molar ratio 1:1. FTIR, 1 H-NMR and 13 C-NMR spectroscopic data revealed that the ligands are N,N,O,O-tetradentate coordinated to the Pd atom through both the azomethine N atoms and phenolic O atoms. From X-ray Crystallographic analysis, it showed that the complex exists as square planar geometry. The synthesized palladium (II) Schiff base complexes were then subjected in catalytic Heck and Suzuki reaction of iodobenzene.

Crystal structure of bis(2-{1-[(E)-(4-fluorobenzyl)imino]ethyl}phenolato-κ2N,O)palladium(II)

“…The N 2 O 2 donor sets of the two chelating Schiff base ligands in the equatorial plane around Pd1 adopt a slightly distorted square-planar coordination geometry. The Pd1-N1 and Pd1-O1 distances (Table 1) are typical of square-planar Pd II complexes, and compare well with those observed in other closely related Pd II complexes (Adrian et al, 2008;Bahron et al, 2014;Wan Ibrahim & Shamsuddin, 2012). The bite angle of the iminomethylphenolate chelate, N1-Pd1-O1 is 88.48 (8) , which is also similar to that in a related Pd II complex (Bahron et al, 2014).…”