Palladium(II) complex of an organotellurium ligand as a catalyst for Suzuki Miyaura coupling: Generation and role of nano-sized Pd3Te2

•Syntheses of [(C6H5)(2-HOC6H4)CH–NH(CH2)3Te–C6H4−4−OMe] (L) and {PdCl(L−H)}.•Exploration of [PdCl(L−H)] as a catalyst for Suzuki coupling reaction.•Generation of Pd3Te2 nanoparticles for the first time during catalysis.•Isolation and characterization of Pd3Te2 NPs.•Role of nanoparticles in total catalytic activity.

Organotellurium ligand (L = (C6H5)(2-HOC6H4)CHNH(CH2)3Te–C6H4−4−OMe) and its palladium complex [PdCl(L−H)](1) have been synthesized and characterized by multinuclei NMR and mass spectra. The L coordinates with Pd(II) in a (N,Te,C−) mode. The complex 1 has been used to catalyze Suzuki–Miyaura coupling (SMC) reaction. The conversions at 0.1 mol% loading of the complex catalyst were good for coupling of phenylboronic acid with various aryl bromides. In case of 4-formylphenylboronic acid catalyst loading needed was higher. In the course of catalysis nanoparticles (NPs) were generated. They were isolated and characterized as Pd3Te2 species (∼1−2 nm size). Catalytic activity of 1 has been ascribed via these NPs. A cocktail process involving both homogeneous and heterogeneous routes appears to carry out catalysis.

Graphical abstractFirst formation of Pd3Te2 nanoparticles (NPs) (size ∼1−2 nm) has been observed in Suzuki–Miyaura coupling of phenylboronic acid with ArBr catalyzed with a Pd-complex of an organotellurium ligand (0.1 mol%). The conversions were >75%. NPs have been characterized with powder-XRD, SEM and TEM.Figure optionsDownload full-size imageDownload as PowerPoint slide