TY - JOUR
T1 - Catalytic oxidation of aromatic hydrocarbons by mono-oxido- alkoxidovanadium(V) complexes of ONNO donor ethylenediaminebis(phenolate) ligands
AU - Debnath, Mainak
AU - Dutta, Arpan
AU - Biswas, Surajit
AU - Das, Kalyan Kumar
AU - Lee, Hon Man
AU - Vícha, Jan
AU - Marek, Radek
AU - Marek, Jaromir
AU - Ali, Mahammad
PY - 2013/1/1
Y1 - 2013/1/1
N2 - Two oxidovanadium(V) complexes, [VVO(L1)(OMe)] (1) and [VVO(L2)(OMe)] (2), with ONNO donor ethylenediamine-bis(phenolate) ligands (H2L1 and H2L2) have been readily synthesized by the reaction between the ligand precursors and VOSO4·5H2O in MeOH, and characterized by physico-chemical techniques and single crystal X-ray diffraction studies. Both complexes 1 and 2 are hexa-coordinated with a pseudo-octahedral geometry in an N2O4 coordination environment and are found to catalyze the oxidation of toluene to benzoic acid and isomers of xylene to the corresponding hydroxy acids, with turnover numbers (TON) over 200, except for o-xylene. On changing the ligand fragments and coordination geometry around the metal centre there is an improvement in the catalytic efficiency, selectivity and also TON of the reaction as compared with the previously reported systems. The reactions were monitored using 51V NMR spectroscopy. Based on mass spectra analysis and 51V NMR studies, the mechanism of the catalytic process has been proposed, employing the formation of oxido-hydroperoxido/hydroxido-peroxido [V(ONNO)(O)(OOH)] ⇔ [V(OH)(ONNO)(O2)] intermediates.
AB - Two oxidovanadium(V) complexes, [VVO(L1)(OMe)] (1) and [VVO(L2)(OMe)] (2), with ONNO donor ethylenediamine-bis(phenolate) ligands (H2L1 and H2L2) have been readily synthesized by the reaction between the ligand precursors and VOSO4·5H2O in MeOH, and characterized by physico-chemical techniques and single crystal X-ray diffraction studies. Both complexes 1 and 2 are hexa-coordinated with a pseudo-octahedral geometry in an N2O4 coordination environment and are found to catalyze the oxidation of toluene to benzoic acid and isomers of xylene to the corresponding hydroxy acids, with turnover numbers (TON) over 200, except for o-xylene. On changing the ligand fragments and coordination geometry around the metal centre there is an improvement in the catalytic efficiency, selectivity and also TON of the reaction as compared with the previously reported systems. The reactions were monitored using 51V NMR spectroscopy. Based on mass spectra analysis and 51V NMR studies, the mechanism of the catalytic process has been proposed, employing the formation of oxido-hydroperoxido/hydroxido-peroxido [V(ONNO)(O)(OOH)] ⇔ [V(OH)(ONNO)(O2)] intermediates.
UR - http://www.scopus.com/inward/record.url?scp=84881539643&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84881539643&partnerID=8YFLogxK
U2 - 10.1016/j.poly.2013.07.013
DO - 10.1016/j.poly.2013.07.013
M3 - Article
AN - SCOPUS:84881539643
VL - 63
SP - 189
EP - 198
JO - Polyhedron
JF - Polyhedron
SN - 0277-5387
ER -