First (Peroxo)vanadium(V) Complex with Heteroligand Formed in Reaction System − Synthesis, Structure and Reactivity of K[VO(O2)(omeida)]·H2O {omeida = N‐[2‐(2‐oxomorpholine‐4‐yl)ethyl]iminodiacetato(2−)}

Abstract

AbstractThe crystalline peroxo complex of vanadium(V), K[VO(O2)(omeida)]·H2O, where omeida is a δ‐lactone derivative, N‐[2‐(2‐oxomorpholine‐4‐yl)ethyl]iminodiacetate(2−), has been obtained by reaction of vanadate with H2O2 and N‐(2‐hydroxyethyl)ethylenediaminetriacetic acid (HEDTA) in acidic aqueous solution at pH = 3 and 278 K. X‐ray analysis revealed a distorted pentagonal‐bipyramidal coordination around the vanadium atom, with a typical cis arrangement of oxo and peroxo ligands in apical and equatorial positions, respectively. Two amino nitrogen atoms of the tetradentate omeida(2−)‐N1,N2,O1,O2 ligand occupy the neighbouring equatorial positions of the pentagonal plane, and two oxygen atoms of carboxymethyl groups bound to the same N1 nitrogen atom are in equatorial and apical positions. The six‐membered lactone ring in omeida was formed in the reaction solution from carboxy and hydroxy groups not involved in coordination with the vanadium atom. The 51V NMR spectra of K[VO(O2)(omeida)]·H2O, and of peroxovanadate/HEDTA/H2O and vanadate/HEDTA/H2O solutions, as well as the 1H NMR spectrum of HEDTA, proved that lactone ring closure proceeds only in peroxovanadate but not vanadate solutions. Spectroscopic investigation of the oxygen transfer reaction from the peroxo ligand in [VO(O2)(omeida)]− to the thiolato sulfur atom in [Co(en)2{S(CH2)2NH2}]2+ or [Co(en)2(cyst)]+, and of the oxidation of N‐acetyl‐L‐cysteine by K[VO(O2)(omeida)]·H2O, revealed much more complicated reaction mechanisms than those of other (amino‐polycarboxylato)monoperoxo complexes of vanadium(V). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)