Coordination and Redox Reaction of Dihydroxyurea With Fe(Ⅲ)

The interaction of dihydroxyurea(DHU) with Fe(Ⅲ) was studied by spectrophotometry and cyclic voltammetry. The results show that DHU forms dark purple complex quickly after mixing with Fe(Ⅲ). Whereas the complex formed is relatively unstable. The decomposition rate constant of the complex k' is estimated to be 0.031min^-1 at 10℃ and c₀(DHU) = c₀(FeCl₃)=1.0×10^-3mol/L. Chelation through the N—O oxygen atom and N—O nitrogen atom can be assumed for the complex. It is found that the innermolecular redox occurred between DHU and Fe(Ⅲ) after the formation of complex in solution. The one-electron transfer from DHU to Fe(Ⅲ) is assumed. Fe(Ⅲ) is reduced to Fe(Ⅱ), at the same time DHU oxidation occurred.