The investigation of Co(II)-dextran complexes

Abstract

Co(II) ion complex compounds were synthesized with reduced dextran (RD) in alkali solutions using CoCl2, 6H2O and isolated in the solid state. UV-VIS spectrophotometric investigations of Co(II) complexes with reduced dextran showed that the complexation of Co(II) ions begins at pH over 7. The formation of Co(II) ion complexes with dextran monomer units was observed at pH 7-13. With increase in solution pH the light absorption maximum of complex solutions shifts to longer wavelengths (bat-hochromic shift) compared with [Co(H2O)6]2+ ion. Dextran complexes with Co(II) ion are formed by the displacement of water molecules from the coordination sphere of cobalt by the OH ligand groups. The spectrophotometric parameters of the investigated complexes are characteristic of a Co(II) ion in octahedral or distorted octahedral coordination with O ligand atoms.

Keywords

• cobalt(II)
• dextran
• complex
• Uv-vis spectrop-hotometry