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Yokoyama S, Azuma S, Eguchi Y, Kodani K, Hasegawa T, Ogo S, Ota H, Guo SX, Boas JF, Zhang J, Bond AM, Ueda T. Vanadium-Containing Keggin-Type Polyoxometalates, [VM 12O 40] 3- and [VVM 11O 40] 4- (M = Mo, W): Structural Characterization and Voltammetric, NMR, and EPR Studies Related to Electrochemical Reduction at Framework and Central Vanadium Sites. Inorg Chem 2024; 63:117-128. [PMID: 38141018 DOI: 10.1021/acs.inorgchem.3c01921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Vanadium is accommodated in both the framework (VoutV) and central positions (VinV) in the Keggin-type polyoxometalates (POMs) [VinVVoutVM11O40]4- (M = Mo, W; VinVVoutVM11) and in the central position in [VinVM12O40]3- (VinVM12). The structures of the VinVVoutVM11 class have been determined by X-ray crystallography and compared to those of VinVM12 reported previously. A major feature of interest with POMs is their capacity for very extensive reduction, particularly when protonation accompanies the electron transfer step. With VinVVoutVM11 and VinVM12 POMs, knowledge as to whether reduction occurs at V or M sites and the concomitant dependence on acidity has been obtained. Frozen solution EPR spectra obtained following bulk electrolysis showed that the one-electron reduction of VinVMo12 occurs at the molybdenum framework site to give VinVMoVMo11. In contrast, EPR spectra of one-electron reduced VinVW12 at <30 K are consistent with the electron being accommodated on the central V atom in a tetrahedral environment to give VinIVW12. In the case of VinVVoutVM11, the initial reduction occurs at the framework VoutV site to give VinVVoutIVM11. The second electron is delocalized over the Mo framework in two-electron reduced VinVVoutIVMoVMo10, whereas it is accommodated on the central V site in VinIVVoutIVW11. The distance between VinIV and VoutIV in VinIVVoutIVW11 estimated as 3.5 ± 0.2 Å from analysis of the EPR spectrum is consistent with that obtained in VinVVoutVW11 from crystallographic data. Simulations of the cyclic voltammograms as a function of CF3SO3H acid concentration for the initial reduction processes provide excellent agreement with experimental data obtained in acetonitrile (0.10 M [n-Bu4N][PF6]) and allowed acid association constants to be estimated and compared with the literature values available for [XVoutVM11O40]n- (X = S (n = 3), P and As (n= 4); M = Mo, W). The interpretation of the voltammetric data is supported by 51V NMR measurements on the oxidized VV forms of the POMs.
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Affiliation(s)
- Sousuke Yokoyama
- Department of Applied Science, Faculty of Science, Kochi University, Kochi 780-8520, Japan
| | - Shinya Azuma
- Department of Applied Science, Faculty of Science, Kochi University, Kochi 780-8520, Japan
| | - Yohei Eguchi
- Department of Applied Science, Faculty of Science, Kochi University, Kochi 780-8520, Japan
| | - Keisuke Kodani
- Department of Applied Science, Faculty of Science, Kochi University, Kochi 780-8520, Japan
| | - Takuya Hasegawa
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Sendai 980-8577, Japan
| | - Shuhei Ogo
- Department of Marine Resource Science, Faculty of Agriculture and Marine Science, Kochi University, Nankoku 780-8502, Japan
- Marine Core Research Institute, Kochi University, Nankoku 783-8502, Japan
| | - Hiromi Ota
- Division of Instrumental Analysis, Department of Instrumental Analysis and Cryogenics, Advanced Science Research Center, Okayama University, Okayama, 700-8530, Japan
| | - Si-Xuan Guo
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - John F Boas
- School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia
| | - Jie Zhang
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - Alan M Bond
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - Tadaharu Ueda
- Department of Marine Resource Science, Faculty of Agriculture and Marine Science, Kochi University, Nankoku 780-8502, Japan
- Marine Core Research Institute, Kochi University, Nankoku 783-8502, Japan
- MEDi Center, Kochi University, Kochi 780-0842, Japan
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Saad RA, Younes G, El-Dakdouki MH, Al-Oweini R. Vanadium-Substituted Polyoxomolybdates for Methylene Blue Adsorption from Aqueous Solutions. J CLUST SCI 2022. [DOI: 10.1007/s10876-021-02130-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Zarroug R, Artetxe B, Ayed B, López X, Ribeiro N, Correia I, Pessoa JC. New phosphotetradecavanadate hybrids: crystal structure, DFT analysis, stability and binding interactions with bio-macromolecules. Dalton Trans 2022; 51:8303-8317. [PMID: 35583072 DOI: 10.1039/d2dt00690a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Two novel bicapped Keggin polyoxidovanadates with organic cations, (C6H8N)5[H4PV14O42]·5H2O (1) and (C6H14N4)2(NH4)[H4PV14O42]·11H2O (2), (PV14O426- = PV14, C6H7N = 3-picoline and C6H12N4 = methenamine) were synthesized. These compounds were isolated and characterized in the solid state and in solution by elemental analysis, powder X-ray diffraction, FTIR, UV-vis, 51V, 31P, 13C and 1H NMR, and fluorescence spectroscopy. Further confirmation of the PV14 structures was obtained by single-crystal X-ray diffraction studies of 1 and 2. The Hirshfeld surface analysis was performed to confirm that within the intermolecular interactions occurring in the two crystals, the O⋯H/H⋯O, O⋯O and H⋯H interactions dominate. The protonation and one-electron reduction of the PV14 moiety were also analysed by means of DFT calculations; besides confirming the protonation sites and correctly predicting the pKa values, the DFT results also indicate that molecular reduction is energetically more favourable in protonated PV14 anions. Upon the addition of PV14 anions to bovine serum albumin (BSA) up to a ratio of 1 : 1, the fluorescence decreased by 45% for both 1 and 2, indicating that the interaction of vanadium-containing species with this protein takes place; log(KSV) values of ca. 5.5 were obtained in both systems. Upon the addition of 1 or 2 to solutions of calf-thymus DNA (ctDNA), changes were observed in the UV-vis absorption and circular dichroism spectra. The significance of the changes observed is discussed considering the several V-containing species that form in the solution.
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Affiliation(s)
- Rim Zarroug
- University of Monastir, Laboratory of Physico-Chemistry of Materials LR01ES19, Faculty of Sciences of Monastir, Tunisia.,Department of Chemistry, Faculty of Sciences, University of Gabes, Tunisia
| | - Beñat Artetxe
- Departamento de Química Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, 48080 Bilbao, Spain
| | - Brahim Ayed
- University of Monastir, Laboratory of Physico-Chemistry of Materials LR01ES19, Faculty of Sciences of Monastir, Tunisia
| | - Xavier López
- Universitat Rovira i Virgili, Departament de Química Física i Inorgànica, c/Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - Nádia Ribeiro
- Centro de Química Estrutural, Institute of Molecular Sciences and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
| | - Isabel Correia
- Centro de Química Estrutural, Institute of Molecular Sciences and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
| | - João Costa Pessoa
- Centro de Química Estrutural, Institute of Molecular Sciences and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
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Bencedira S, Bechiri O, Djenouhat M, Boulkra M. Cobalt-Substituted Heteropolyanion: Synthesis, Characterization, and Application to Oxidation of an Organic Dye in an Aqueous Medium. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2020. [DOI: 10.1007/s13369-020-04392-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Modvig A, Kumpidet C, Riisager A, Albert J. Ru-Doped Wells-Dawson Polyoxometalate as Efficient Catalyst for Glycerol Hydrogenolysis to Propanediols. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E2175. [PMID: 31284581 PMCID: PMC6651741 DOI: 10.3390/ma12132175] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/25/2019] [Accepted: 06/27/2019] [Indexed: 02/04/2023]
Abstract
A Ru-doped phospho-tungstic Wells-Dawson polyoxometalate (POM) was successfully applied as homogeneous catalyst for glycerol hydrogenolysis in aqueous media. The synthesized compound showed superior catalytic activity compared to classical homogeneous/heterogeneous Ru catalysts like RuCl3 and Ru/C under identical reaction conditions, whereas the analogous POM doped with Pd or Pt proved far less activity. Detailed characterization of the POMs was performed using 31P-NMR to identify characteristic phosphorous peaks of the heteroatoms, infrared spectroscopy (ATR-FTIR) to confirm characteristic P-O and W-O-W vibrations, powder XRD for comparison of crystal structures, and X-ray fluorescence (XRF) and inductive-coupled plasma (ICP) analysis to determine elemental composition. Variation of the reaction parameters for the best performing Ru-doped POM catalyst showed that substrate concentration played an important role for both product selectivity and conversion. Moreover, medium hydrogen pressure and high stirring speed were key factors to obtain highly selective conversion of glycerol to 1,2-propanediol.
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Affiliation(s)
- Amalie Modvig
- Centre for Catalysis and Sustainable Chemistry, Department of Chemistry, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Chiraphat Kumpidet
- Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany
| | - Anders Riisager
- Centre for Catalysis and Sustainable Chemistry, Department of Chemistry, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Jakob Albert
- Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany.
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Douvas AM, Tsikritzis D, Tselios C, Haider A, Mougharbel AS, Kortz U, Hiskia A, Coutsolelos AG, Palilis LC, Vasilopoulou M, Kennou S, Argitis P. Multi-electron reduction of Wells-Dawson polyoxometalate films onto metallic, semiconducting and dielectric substrates. Phys Chem Chem Phys 2018; 21:427-437. [PMID: 30534673 DOI: 10.1039/c8cp07101b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The investigation of conditions allowing multi-electron reduction and reoxidation of polyoxometalate (POM) films onto solid substrates is considered an issue of critical importance for their successful incorporation in electronic devices, different types of sensors and catalytic systems. In the present paper, the rich multi-electron redox chemistry of films of Wells-Dawson ammonium salts, namely (NH4)6P2Mo18O62 and (NH4)6P2W18O62, on top of metallic (Al), semiconducting (ITO) and dielectric (SiO2) substrates under ambient conditions is investigated. The respective Keggin heteropolyacids, H3PMo12O40 and H3PW12O40, are also investigated for comparison. On Al substrates, the Wells-Dawson ammonium salts are found to be significantly more reduced (4-6e-) compared to the respective Keggin heteropolyacids (∼2e-), in accordance with their deeper lying lowest unoccupied molecular orbital (LUMO) level. Subsequent thermal treatment in air results in reoxidation of the initially highly reduced POM films. Similar behavior is found on ITO substrates, but in initially less reduced (2-4e-) Wells-Dawson POM films. On the other hand, on SiO2 substrates, the thermal reduction of (NH4)6P2Mo18O62 film is observed and attributed to the thermal oxidation of ammonium counterions by [P2Mo18O62]6- anions. Overall, the multi-electron reduction of Wells-Dawson ammonium salts onto metallic and semiconducting substrates (Al, ITO) is determined by the relative position of the LUMO level of POMs in relation to the Fermi level of the substrate (i.e. substrate work function) and affected in a synergistic way by the presence of ammonium counterions. In contrast, on dielectric substrates (SiO2) the reduction of Wells-Dawson POMs ((NH4)6P2Mo18O62) is attributed only to the oxidation of ammonium counterions.
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Affiliation(s)
- Antonios M Douvas
- Institute of Nanoscience and Nanotechnology (INN), National Center for Scientific Research (NCSR) "Demokritos", 15341 Agia Paraskevi, Attica, Greece.
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Molybdenum-substituted polyoxometalate as stable shuttle redox mediator for visible light driven Z-scheme water splitting system. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.12.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Banisharif F, Dehghani M, Capel-Sanchez M, Campos-Martin J. Extractive-oxidative removals of dibenzothiophene and quinoline using vanadium substituted Dawson emulsion catalyst and ionic liquid based solvents. J IND ENG CHEM 2017. [DOI: 10.1016/j.jiec.2016.12.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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The Enhancement of the Formation of Wells–Dawson-Type Polyoxometalates by the Addition of High Concentrations of LiCl. J CLUST SCI 2015. [DOI: 10.1007/s10876-015-0946-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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