Copper(II) complexes with 4-(3,5-dimethyl-1 H-pyrazol-1-yl)-2-methyl-6-phenylpyrimidine: Syntheses, crystal structures and catalytic activity in ethylene polymerization

Abstract

The copper(II) complexes CuLCl 2 ( 1) and CuLBr 2 ( 2), with the chelating pyrazolylpyrimidine ligand 4-(3,5-dimethyl-1 H-pyrazol-1-yl)-2-methyl-6-phenylpyrimidine (L), have been synthesized. A single crystal X-ray diffraction study revealed that 1 and 2 have molecular mononuclear structures. The molecules of 1 and 2 form chains in the crystal structures of these compounds due to the formation of π–π-stacking interactions between the pyrimidine and the phenyl rings. The complexes, in combination with the co-catalyst methylaluminoxane (MAO), reveal catalytic activity in ethylene polymerization, while the free ligand L is inactive.