Structural characterization of copper complexes containing N, N′-di(6-methyl-2-pyridyl)formamidine

Abstract

The reactions of N, N′-di(6-methyl-2-pyridyl)formamidine (HDMepyF) with copper halide produced complexes of the types CuCl 2(HDMepyF) ( 1), Cu 2X 4(HDMepyF) 2 (X=Cl, 2; X=Br, 3), Cu 4I 4(HDMepyF) 2 ( 4), and [Cu 2(HDMepyF) 2](PF 6) 2 ( 5). All complexes were characterized by X-ray crystallography. The structure of 1 is tetrahedral with the Cu(II) center chelated by one HDMepyF ligand and coordinated by two chloride ligands. Complexes 2 and 3 are dinuclear complexes, in which the two Cu(II) centers are bridged by two halide atoms. Each Cu(II) metal center are also coordinated by one terminal halide atom and chelated by one HDMepyF ligand, forming a distorted square-pyramidal geometry. Complex 4 is tetranuclear with the four copper atoms forming a parallelogram and each Cu atom being in a three-coordination environment. One iodo atom and one HDMepyF ligand bridge two adjacent copper atoms. In complexes 1– 4, the neutral HDMepyF ligands coordinate to the metal centers through one amine nitrogen atom and one adjacent pyridine nitrogen atom. In dinuclear complex 5, the HDMepyF ligands coordinate to the Cu(I) ions in a tridentate fashion, forming a chelating and a bridging bonding modes. The molecules of 5 are chiral due to the ligand constraints and each Cu atom forms a trigonal-planar geometry. All the HDMepyF ligands in complexes 1– 5 adopt the s- cis, s- trans conformation.