Synthesis, structure, and catalytic properties of copper, palladium and cobalt complexes containing an N,O-type bidentate thiazoline ligand

•CoIII, CuII and PdII complexes containing 2-(2′-hydroxyphenyl)-2-thiazoline are synthesized.•The copper(II) complex is applied for the azide–alkyne cycloaddition.•Excellent yield has been achieved.

Synthesis of CoIII, CuII and PdII complexes containing 2-(2′-hydroxyphenyl)-2-thiazoline as a bidentate O,N-donor thiazoline ligand (tzol), [Co(tzol)3] (1), [Cu(tzol)2] (2), [Pd(tzol)2] (3) and characterization by various techniques such as IR, mass spectrometry, and elemental analysis are reported. The novel complex 1 was also characterized by X-ray crystallography. The structures of complexes 2 and 3 were analyzed by density functional theory. The representative synthetic procedure involves the reaction of a metal acetate with the thiazoline ligand in methanol. The catalytic activity of complexes 1–3 for azide–alkyne cycloaddition was tested. The reaction conditions for the azide–alkyne cycloaddition were optimized by varying the catalyst loading, temperature, and time of reaction.

Graphical abstractThe azide–alkyne cycloaddition reactions were conducted by a copper(II) complex of 2-(2′-hydroxyphenyl)-2-thiazoline as a ligand without any additional reducing/oxidizing agents.Figure optionsDownload full-size imageDownload as PowerPoint slide