ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Spectrophotometric study of nitrate and bromo-nitrate-Ni(II) complexes in acetone

T. Šramko

Slovak Technical University, Bratislava

Abstract: Spectrophotometric studies of the systems Ni(ClO₄)₂.6H₂O-LiNO₃- Me₂CO (1) and Ni(ClO₄)₂.6H₂O-LiNO₃-LiBr-Me₂CO (2) indicated formation of several nitrate-Ni(II) and bromonitrate-Ni(II) complexes. The octahedral nitrate-Ni complexes showed ratios of Ni:NO₃ = 1:1, 1:2, and higher. These complexes are coordinatively satd. by the mol. of the solvent. Application of the isomolar-series method indicated that the presence of the nitrate ion as a ligand in the inner Ni (II) coordination sphere stabilizes the proportions of Ni:Br:NO₃ as 1:1:1 and 1:1:2. It is assumed that the heterocomplexes of Ni(II) ligated with nitrate or bromine ions are coordinatively satd. and have the octahedral structure. Equil. changes in 1 and 2 with molar ratios Ni:Br = 1:1, 1:1.5, 1:3, and 1:4 were investigated by using the methods of univariant-change and spectroscopy. Existence of disproportional equil. of the soln. of NiBr₂ in acetone was demonstrated and proved that the formation of the heterocomplexes Ni-Br-NO₃ is influenced by substitution of the solvent in the [NiBr (solvent)n]+ complex.

Full paper in Portable Document Format: 176a390.pdf (in Slovak)

Chemical Papers 17 (6) 390–401 (1963)