Transition-metal complexes of the 2,3-dipyridylquinoxalines. Part III. Cobalt(II), nickel(II), and copper(II) halide derivatives of 6-methyl-2,3-di-(2-pyridyl)quinoxaline and 6,7-dimethyl-2,3-di-(2-pyridyl)quinoxaline

Abstract

The cobalt(II), nickel(II), and copper(II) halide complexes of 6-methyl-2,3-di-(2-pyridyl)quinoxaline (dpmq) and 6,7-dimethyl-2,3-di-(2-pyridyl)quinoxaline (dpdmq) are described, and the structures interpreted on the basis of magnetic and spectral data. For cobalt, the octahedral complexes CoX2L (L = dpmq, X = Cl, Br; L = dpdmq, X = Br, l) and the tetrahedral complexes Col2(dpmq) and CoCl2(dpdmq) were isolated. The nickel complexes, NiX2L (L = dpmq, X = Cl, Br, l; L = dpdmq, X = Cl, Br) and Nil2(dpdmq)(H2O)2 have octahedral geometries. All the CuII complexes have the stoicheiometry CuX2L, but three different geometries are apparent. CuCl2(dpmq) and CuBr2(dpdmq) are distorted octahedral, CuBr2(dpmq) has a square planar structure, and CuCl2(dpdmq) is believed to be distorted tetrahedral.