Mimicking peroxidase activity by a polymer-supported oxidovanadium(IV) Schiff base complex derived from salicylaldehyde and 1,3-diamino-2-hydroxypropane.

ABSTRACT

The polymer-supported oxidovanadium(IV) complex PS-[V(IV)O(sal-dahp)] (2) (PS=chloromethylated polystyrene crosslinked with 5% divinylbenzene, and H3sal-dahp=dibasic pentadentate ligand derived from salicylaldehyde and 1,3-diamino-2-hydroxypropane) was prepared from the corresponding monomeric oxidovanadium(IV) complex [V(IV)O(Hsal-dahp)(DMSO)] (1), characterized and successfully used as catalyst for the peroxidase-like oxidation of pyrogallol. The oxidation of pyrogallol to purpurogallin with PS-[V(IV)O(sal-dahp)] (2) was achieved under mild conditions at pH7 buffered solution. Plausible intermediate species formed during peroxidase mimicking experiments are proposed, by studying the model complex [V(IV)O(Hsal-dahp)(DMSO)] (1) by UV-visible and (51)V NMR spectroscopies. The high peroxidase mimicking ability of polymer-supported complex 2, its stability in a wide pH range, the easy separation from the reaction media, and the reusability without considerable decrease in activity, suggest that this heterogeneous catalyst has high potential for application in sustainable industrial catalysis.