ASPARTAMIDE POLYHYDROXAMIC ACIDS - SYNTHESIS AND IRON(III) COMPLEXES

Several linear and cross-linked poly[alpha,beta-(N-hydroxy-D,L-asparta mide)] derivatives (polyhydroxamic acids) were synthesized by aminolys is of poly-D,L-(2,5-dioxo-1,3-pyrrolidinediyl) (polysuccinimide; PSI) with the corresponding hydroxylamines. Aminolysis of the succinimide ( SI) units in PSI with hydroxylamine or N-methylhydroxylamine was eithe r complete or only partial, depending on the molar ratio of the SI-uni ts and the hydroxylamine. Copolymers with partially opened SI rings we re subjected to further aminolysis by 2-aminoethanol, di(2-hydroxyethy l)amine, butylamine, 2-phenylethylamine, 1,2-diaminoethane, and 1,6-di aminohexane. Use of diamines led to cross-linked polymers. Polyhydroxa mic acids differed in the average relative molecular mass, the number and spacing between the hydroxamic acid groups and in their solubility . The polyhydroxamic acids formed colored complexes with the iron(III) ions. Stability constants for the (III)-poly[alpha,beta-(N-hydroxy)-D ,L-aspartamide] complexes were determined by spectrophotometric titrat ion. Values of the equilibrium quotients at 25 degrees C were calculat ed and confirmed to be: Q(1) = (1.0 +/- 0.4) x 10(2), Q(2) = (1.3 +/- 0.7) x 10(-2).