Abstract
Reactions of [VCl 3 (thf) 3 ] or VBr 3 with 2,2′-bipyridine (bpy) or 1,10‐-phenanthroline (phen) in a 1:1 molar ratio in air under solventothermal conditions has afforded polymeric oxidovanadium(IV) four complexes 1‒4 of a general formula [VO(L)X 2 ] n (L = bpy, phen and X = Cl, Br). Monomeric complex [VO(DMF)(phen)Br 2 ] (4a) has been obtained by the treatment of compound 4 with DMF. The complexes were characterized by IR spectroscopy and elemental analysis. The crystal structures of 3 and 4a were determined by an X‐-ray diffraction (XRD) analysis. The {VOBr 2 (bpy)} fragments in 3 form infinite chains due to the V = O…V interactions. The vanadium atom has a distorted octahedral coordination environment. Complexes 1‒4 have been tested as catalysts in the homogeneous oxidation of alkanes (to produce corresponding alkyl hydroperoxides which can be easily reduced to alcohols by PPh 3 ) and alcohols (to corresponding ketones) with H 2 O 2 or tert‐-butyl hydroperoxide in MeCN. Compound 1 exhibited the highest activity. The mechanism of alkane oxidation was established using experimental selectivity and kinetic data and theoretical DFT calculations. The mechanism is of the Fenton type involving the generation of HO • radicals.
Original language | English |
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Article number | 217 |
Number of pages | 20 |
Journal | Catalysts |
Volume | 9 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1 Mar 2019 |
Keywords
- Alkanes
- Alkyl hydroperoxides
- DFT calculations
- Fenton mechanism
- Heterocyclic diimines
- Hydrogen peroxide
- Oxidovanadium(IV) complexes
- Reaction mechanism
- alkyl hydroperoxides
- alkanes
- CRYSTAL-STRUCTURE
- hydrogen peroxide
- VANADIUM COMPLEXES
- O-2-H2O2-VANADIUM DERIVATIVE-PYRAZINE-2-CARBOXYLIC ACID
- HYDROCARBON OXYGENATIONS
- heterocyclic diimines
- reaction mechanism
- AEROBIC OXIDATION
- HYDROGEN-PEROXIDE
- PYRAZINE-2-CARBOXYLIC ACID
- oxidovanadium(IV) complexes
- SCHIFF-BASE LIGANDS
- H2O2-VANADIUM COMPLEX-PYRAZINE-2-CARBOXYLIC ACID
- OXOVANADIUM(IV) COMPLEXES