Design of a Copper(II) Complex with Tetradentate Bis‐Benzotriazole‐Appended Bipyridine Ligand and its Catalytic Application in A3 Coupling Reaction.

In this report, a Cu(II) complex Cu‐L4 containing a new tetradentate benzotriazole‐appended bipyridine ligand was synthesized and characterized fully via spectroscopic and crystallographic techniques. The crystal structure of the complex revealed that the ligand is bound to copper in a tetradentate fashion in a plane and the axial positions are occupied by an anion and a solvent molecule, resulting in a distorted octahedral geometry of the complex in solid‐state. This air‐stable complex was utilized as homogeneous precatalyst for the synthesis of several propargylamine derivatives by 3‐component A3 coupling reactions of aldehydes, amines, and alkynes under aerial atmosphere. [ABSTRACT FROM AUTHOR]