Fist oxidovanadium complexes containing chiral derivatives of dihydrophenanthroline and diazafluorene

Fomenko, Iakov S.; Gushchin, Artem L.; Ткачев, А. В.; Vasilyev, Evgene S.; Abramov, Pavel A.; Nadolinny, V. A.; Syrokvashin, Mikhail M.; Sokolov, Maxim N.

doi:10.1016/j.poly.2017.07.003

Cited by 15 publications

(14 citation statements)

References 45 publications

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“…By applying method B, the yield of complex 3 was increased from 21 to 83%. Nevertheless, method A was also successfully used to synthesize other oxidovanadium complexes with diimine ligands [ 20 , 42 , 43 , 44 , 45 , 46 , 47 ].…”

Section: Resultsmentioning

confidence: 99%

Novel Oxidovanadium Complexes with Redox-Active R-Mian and R-Bian Ligands: Synthesis, Structure, Redox and Catalytic Properties

et al. 2021

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A new monoiminoacenaphthenone 3,5-(CF3)2C6H3-mian (complex 2) was synthesized and further exploited, along with the already known monoiminoacenaphthenone dpp-mian, to obtain oxidovanadium(IV) complexes [VOCl2(dpp-mian)(CH3CN)] (3) and [VOCl(3,5-(CF3)2C6H3-bian)(H2O)][VOCl3(3,5-(CF3)2C6H3-bian)]·2.85DME (4) from [VOCl2(CH3CN)2(H2O)] (1) or [VCl3(THF)3]. The structure of all compounds was determined using X-ray structural analysis. The vanadium atom in these structures has an octahedral coordination environment. Complex 4 has an unexpected structure. Firstly, it contains 3,5-(CF3)2C6H3-bian instead of 3,5-(CF3)2C6H3-mian. Secondly, it has a binuclear structure, in contrast to 3, in which two oxovanadium parts are linked to each other through V=O···V interaction. This interaction is non-covalent in origin, according to DFT calculations. In structures 2 and 3, non-covalent π-π staking interactions between acenaphthene moieties of the neighboring molecules (distances are 3.36–3.40 Å) with an estimated energy of 3 kcal/mol were also found. The redox properties of the obtained compounds were studied using cyclic voltammetry in solution. In all cases, the reduction processes initiated by the redox-active nature of the mian or bian ligand were identified. The paramagnetic nature of complexes 3 and 4 has been proven by EPR spectroscopy. Complexes 3 and 4 exhibited high catalytic activity in the oxidation of alkanes and alcohols with peroxides. The yields of products of cyclohexane oxidation were 43% (complex 3) and 27% (complex 4). Based on the data regarding the study of regio- and bond-selectivity, it was concluded that hydroxyl radicals play the most crucial role in the reaction. The initial products in the reactions with alkanes are alkyl hydroperoxides, which are easily reduced to their corresponding alcohols by the action of triphenylphosphine (PPh3). According to the DFT calculations, the difference in the catalytic activity of 3 and 4 is most likely associated with a different mechanism for the generation of ·OH radicals. For complex 4 with electron-withdrawing CF3 substituents at the diimine ligand, an alternative mechanism, different from Fenton’s and involving a redox-active ligand, is assumed.

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Section: Resultsmentioning

confidence: 99%

Novel Oxidovanadium Complexes with Redox-Active R-Mian and R-Bian Ligands: Synthesis, Structure, Redox and Catalytic Properties

et al. 2021

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“…The line splitting varies from 8.98 mT to 11.16 mT, and the line half-width varies from 1.28 mT to 2.4 mT, due to the vanadium complex mobility in solution and to an incomplete averaging of the g tensor anisotropy. complexes [10,42]. The EPR spectrum of solid 1 reveals a single-line signal with a half-width width (∆H1/2) of 8.6 mT and g = 1.967 due to the exchange interaction between paramagnetic vanadium ions (Fig.…”

Section: Epr Spectramentioning

confidence: 99%

“…The title complex was synthesized from vanadium(III) chloride (VCl3) and 4,4'-di-tertbutyl-2,2'-bipyridine (dbbpy), with concomitant oxidation in air to give the {V=O} 2+ moiety, see Scheme 1. The same synthetic procedure was previously used for the preparation of other oxidovanadium(IV) complexes with 2,2'-bipyridine, 1,10-phenathroline [31], bis(N-(2,6diisopropylphenyl)-imino)acenaphthene (dpp-bian) [10], dehydrophenanthroline and diazofluorene ligands [42]. The reaction of VCl3 with 4,4'-di-tert-butyl-2,2'-bipyridine (dbbpy) The IR spectrum of 1 shows a strong band at 989 cm -1 , assigned to a V=O stretching mode in agreement with those reported for other oxidovanadium(IV) complexes [10,[44][45][46].…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

An oxidovanadium(IV) complex with 4,4′-di-tert-butyl-2,2′-bipyridine ligand: Synthesis, structure and catalyzed cyclooctene epoxidation

et al. 2020

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The interaction of vanadium(III) chloride (VCl3) with 4,4'-di-tert-butyl-2,2'-bipyridine (dbbpy) in air resulted in the monomeric oxidovanadium(IV) complex [VOCl2(dbbpy)(H2O)] (1) in high yield. The complex was characterized by IR and EPR spectroscopies, by elemental analysis, and by single crystal X-ray diffraction analysis. The vanadium atom has a distorted octahedral coordination environment. The EPR spectrum of 1 in CH2Cl2 demonstrates an eightline signal typical of vanadium(IV) with a d 1 electronic configuration. Complex 1 exhibits catalytic activity in the cyclooctene oxidation with tert-butyl hydroperoxide (TBHP) in CHCl3. Detailed EPR, NMR and GC-MS studies of the reaction revealed a few mechanistic details and the nature of by-products that are generated by involvement of the chloroform solvent.

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“…Vanadium trichloride adduct with tetrahydrofuran ([VCl 3 (thf) 3 ]) and vanadium tribromide (VBr 3 ) were used as starting compounds which were oxidized during the reaction in air to give the V = O moiety (Scheme 1). This synthetic procedure was previously applied for the synthesis of other oxidovanadium(IV) complexes with chiral dehydrophenanthroline and diazofluorene ligands as well as with the redox-active bis(N-(2,6-diisopropylphenyl)imino)acenaphthene (dpp-bian) ligand [25,63]. The reactions of the corresponding vanadium precursor and 2,2 -bipyridine (bpy) or 1,10-phenanthroline (phen) in a 1:1 molar ratio resulted in microcrystalline products in yields ranging from moderate to high.…”

Section: Synthesis and Characterization Of Compounds 1-4amentioning

confidence: 99%

“…Various vanadium derivatives are known to catalyze the oxidations of organic compounds with inorganic and organic peroxides (see reviews [18,19] and original papers [20][21][22]). Most oxidovanadium(IV) complexes have monomeric structures with an octahedral or square-pyramidal coordination geometry of vanadium [23][24][25][26][27][28][29][30][31][32]. Polynuclear linear chain structures ({V = O .…”

Section: Introductionmentioning

confidence: 99%

New Oxidovanadium(IV) Complexes with 2,2′-bipyridine and 1,10-phenathroline Ligands: Synthesis, Structure and High Catalytic Activity in Oxidations of Alkanes and Alcohols with Peroxides

et al. 2019

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Reactions of [VCl3(thf)3] or VBr3 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)X2]n (L = bpy, phen and X = Cl, Br). Monomeric complex [VO(DMF)(phen)Br2] (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 {VOBr2(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 PPh3) and alcohols (to corresponding ketones) with H2O2 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.

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Fist oxidovanadium complexes containing chiral derivatives of dihydrophenanthroline and diazafluorene

Cited by 15 publications

References 45 publications

Novel Oxidovanadium Complexes with Redox-Active R-Mian and R-Bian Ligands: Synthesis, Structure, Redox and Catalytic Properties

Novel Oxidovanadium Complexes with Redox-Active R-Mian and R-Bian Ligands: Synthesis, Structure, Redox and Catalytic Properties

An oxidovanadium(IV) complex with 4,4′-di-tert-butyl-2,2′-bipyridine ligand: Synthesis, structure and catalyzed cyclooctene epoxidation

New Oxidovanadium(IV) Complexes with 2,2′-bipyridine and 1,10-phenathroline Ligands: Synthesis, Structure and High Catalytic Activity in Oxidations of Alkanes and Alcohols with Peroxides

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