Metal complexes of azopyridines. Part III. Complexes of nickel(II) and copper(II) with 2,2′-azopyridine

Abstract

2,2′-Azopyridine has been used to form metal halide complexes of the types MX2,2L, MX2,L, MX2,½L (M = Cu; X = Cl or Br; M = Ni; X = Cl) and NiCl2,½L,H2O; and metal sulphate complexes of the type MSO4,½L,nH2O (M = Cu, n= 1; M = Ni, n= 2). The results of i.r. (450–80 cm.–1) and electronic spectral measurements suggest that in CuX2,2L (X = Cl or Br) and in the complexes of nickel chloride and of both metal sulphates, the metal atoms are six-co-ordinate. For CuX2,½L (X = Cl or Br) the low-frequency i.r. results are compatible with structures in which the azopyridine ligands bridge planar or tetrahedrally co-ordinated Cu2X4 units (the latter geometry being indicated by the electronic spectra), whereas CuX2,L (X = Cl or Br) contain linear CuX2 groupings linked by amine bridges.