Semicarbazone of starch dialdehyde and its complexes with metal ions

Potato starch was oxidised with periodate to 14% dialdehyde product that was converted into its semicarbazone. Complexes of the semicarbazone with Ca, Cd, Co (II), Cu (II), Fe (II), Mg, Mn (II), Ni (II), Pb (II) and Zn are described. IR spectral analyses on the soluble fractions of the complexes showed that the carbonyl oxygen atoms and the CN nitrogen atoms of the semicarbazone are involved in chelation of the metal atoms. The thermal analysis of complexes revealed two-step decomposition of the ligand and three-step decomposition of complexes. Particular metal ions are chelated to a different extent. One in six semicarbazone moiety is engaged in co-ordination of Cu (II), and in bonding of Mn (II) one in 40 semicarbazone moiety is involved.