The infrared spectra of ethylenediamine complexes—II. Tris-, bis- and mono(ethylenediamine) complexes of metal(II) halides

Abstract

The i.r. spectra of the complexes M(en) 3X 2 (M = Mn, Fe, Co, Ni, Cu, Zn), trans-Cu(en) 2X 2, Ni(en) 2X 2 and M(en)X 2 (M = Ni, Cu, Zn; X = Cl, Br, I) have been studied. Assignments are proposed for the tris(ethylenediamine) complexes on the basis of 15N-, N 2D 4- and C 2D 4-labelling of en and the effects of metal ion substitution in relation to our earlier study of [M(en) 3]SO 4 complexes. Assignments for the bis(ethylenediamine) complexes are based on our observations of halogen-sensitivity and earlier studies on metal isotope labelling and ligand deuteration of the halide complexes and a normal coordinate analysis of the [Cu(en) 2] 2+ species. The spectra of the halide complexes have been extended below 200 cm −1 for the first time. Finally, the spectra of the mono(ethylenediamine) complexes are discussed in relation to their known or probable structures.