Phosphine-Free Bis(imino)pyridine-Based Pincer Palladium(II) Complexes as Catalysts for C-H Bond Arylation of Azoles with Aryl Iodides

Palladium pincer complexes have been shown to catalyze various organic transformations. Bis(imino)pyridine-based palladium(II) complexes have been synthesized from the reactions between corresponding bis(imino)pyridine ligands and PdCl2(CH3CN)2 in acetonitrile as a solvent. All three palladium pincer complexes of general formula [(N & BOTTOM;N & BOTTOM;N)PdCl][PdCl3] and [(N & BOTTOM;N & BOTTOM;N)PdCl][PF6] have been characterized by NMR, IR, Mass and Elemental analysis studies. The catalytic activity of these palladium pincer complexes in direct C-H bond arylation of azoles with aryl iodides was also investigated. At a catalyst loading of 0.25 mol%, the palladium complexes were found to be effective precatalysts in the direct C-H bond arylation of azoles with aryl iodide. New [N & BOTTOM;N & BOTTOM;N] pincer palladium(II) complexes with bis(imino)pyridine ligands have been synthesized and well characterized. The pincer palladium(II) complexes are acted as effective catalysts for the arylation of azoles with aryl iodides in the presence of CuI as co-catalyst.image