Spectroscopic Characterization of Cobalt (II) Complexes with Reduced Low-Molar Dextran Derivatives

Abstract

Summary The formation of Co(II) ion complexes with reduced low-molar dextran (RLMD, Mw 5000 g/mol) was studied at the pH range from 7.0 to 13.5. The cobalt content in synthesized Co(II)-RLMD complexes was ~3–12% (AAS) and it generally increases with pH. Co(II)-RLMD complexes were characterized by UV-Vis spectrophotometry and FTIR spectroscopy. UV-Vis data for synthesized complexes indicate tetragonally distorted Oh coordination of Co(II) ions with O atoms from ligand. The presence of IR bands at 765 cm−1 and 910 cm−1 in Co(II)-RLMD complexes indicates the existence of α-(1→6)O-glycosidic bonds. The similarities in the γ(C–H) range of the IR spectra indicate that there is no difference in the conformation of the glucopyranose units in RLMD and Co(II)-RLMD complexes. The occurrence of water molecules in Co(II)-RLMD complexes was confirmed by FTIR spectroscopy of deuterated samples.