EPR investigation of Cu(II)-complexes with nitrogen derivatives of dialdehyde starch

Dialdehyde starch obtained by periodate oxidation from potato starch was converted into its disemicarbazone (DSC), dithiosemicarbazone (DTSC), dihydrazone (DHZ) and dioxime (DOX). The Cu(II) complexes of these compounds were prepared and characterized by Raman and EPR spectra, as well as by the measurements of magnetic susceptibility. EPR investigations showed that two types of complexes with different surroundings of copper centres existed in each starch derivative. Besides nitrogen atoms of the C=N moiety and sulphur atoms of the C=S moiety, also oxygen atoms from starch hydroxyl groups and/or water molecule were proposed as the coordination sites for the central copper ions.