Transition-metal complexes of the 2,3-dipyridylquinoxalines. Part II. Cobalt(II), nickel(II), and copper(II) halide derivatives of 2,3-di-(6-methyl-2-pyridyl)quinoxaline

Abstract

The cobalt(II), nickel(II), and copper(II) halide complexes of 2,3-di-(6-methyl-2-pyridyl)quinoxaline (dmpyq) are described, and the structures are interpreted on the basis of magnetic and spectral data. For cobalt, the tetrahedral complexes CoX₂(dmpyq)(X = Cl, Br, and l) were isolated, and for nickel the complexes NiX₂(dmpyq)(X = Cl and Br) were found to be distorted octahedral. Copper complexes of stoicheiometry CuX₂(dmpyq)(H₂O)₂ were obtained, and are believed to contain five-co-ordinate Cu^II, the formulae of the complexes being [Cu(dmpyq)-(H₂O)₂]X₂. The solution properties of the complexes are described and interpreted.