Histidine-Containing Bisperoxovanadium(V) Compounds: Insight Into the Solution Structure by an ESI-MS and51V-NMR Comparative Study

Abstract

ESI mass spectrometry and 51V‐NMR spectroscopy have been used to study the reactions occurring between bisperoxo vanadates and a number of histidine and histidine‐like ligands, in aqueous alcoholic solutions. Coordination of one and two molecules of ligand is observed with all the compounds investigated affording [VO5L]− and [VO52L]−, respectively. Characterization of these species has been achieved by MSn experiments, which have allowed specific fragmentations of the peroxidic moiety to be distinguished. In particular, with [VO52L]−, two distinct modes of decomposition were observed, depending on the presence in the ligand of a free carboxylic function. – Possible biochemical implications related to vanadium haloperoxidase enzymes are discussed.

Vanadium catalyzed oxidation with hydrogen peroxide

“…To this scope a protocol has been suggested [11] which uses a combination of multinuclear NMR, ESI-MS spectroscopy and theoretical calculations. The majority of the experimental work has been carried out in aqueous alcoholic solutions, and in some case also in the presence of appropriate ligands, in order to model some of the natural conditions where vanadium dependent haloperoxidase enzymes (VHPO) work.…”

“…In order to gain direct evidence on the occurrence, composition and structure of the postulated ''bromine equivalent" intermediate, the V/H 2 O 2 /H + system was further investigated by ESI-MS analysis, using a mixed water-alcohol infusion solvent [12]. À is a feasible process both in solution and in gas-phase [6,11,40]. The stabilization energies obtained by theoretical calculations for the first coordination are in the range 90-133 KJ/mol, depending on L, whereas those associated to the second coordination are lower.…”

“…All our work carried out in the field of solution characterization of vanadates and peroxidovanadates is assembled, in a concise form, in rather recent reviews [7,8] and interested readers are thus referred there or to the original papers [6,[9][10][11][12], nevertheless, some of the main figures in the field will be presented here.…”

ESI–IT–MS n and DFT calculation for electron affinities of bimetallic oxovanadium complexes

“…Electrospray ionization mass spectrometry (ESI-MS) is a useful approach for the characterization of oxovanadium complexes [10][11][12][13][14][15][16]. In mass spectrometry, the fragmentation behavior of radical ions has been found to be rich and fascinating, especially in the field of peptide sequencing [17][18][19].…”

First‐principle calculations for the active centers in vanadium‐containing chloroperoxidase and its functional models: Geometrical and spectral properties

“…To the best of our knowledge, there exist in literature only a few theoretical works on models for the active site of vanadium‐dependent haloperoxidases, and not one of them concerns spectral properties. Conte and Bortolini have employed RHF and DFT methods in addition to NMR and ESI‐MS techniques to study water coordination and the influence of the apical ligand on the structure and relative stabilities of vanadium peroxo species and to address preferences in protonated states 15–17.…”