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Faleiro L, Marques A, Martins J, Jordão L, Nogueira I, Gumerova NI, Rompel A, Aureliano M. The Preyssler-Type Polyoxotungstate Exhibits Anti-Quorum Sensing, Antibiofilm, and Antiviral Activities. BIOLOGY 2022; 11:biology11070994. [PMID: 36101375 PMCID: PMC9311568 DOI: 10.3390/biology11070994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/16/2022] [Accepted: 06/21/2022] [Indexed: 12/31/2022]
Abstract
The increase in bacterial resistance to antibiotics has led researchers to find new compounds or find combinations between different compounds with potential antibacterial action and with the ability to prevent the development of antibiotic resistance. Polyoxotungstates (POTs) are inorganic clusters that may fulfill that need, either individually or in combination with antibiotics. Herein, we report the ability of the polyoxotungstates (POTs) with Wells-Dawson P2W18, P2W17, P2W15, and Preyssler P5W30 type structures to differently affect Gram-negative and Gram-positive microorganisms, either susceptible or resistant to antibiotics. The compound P5W30 showed the highest activity against the majority of the tested bacterial strains in comparison with the other tested POTs (P2W15, P2W17 and P2W18) that did not show inhibition zones for the Gram-negative bacteria, A. baumanii I73775, E. coli DSM 1077, E. coli I73194, K. pneumoniae I7092374, and P. aeruginosa C46281). Generally, the results evidenced that Gram-positive bacteria are more susceptible to the POTs tested. The compound P5W30 was the one most active against S. aureus ATCC 6538 and MRSA16, reaching <0.83 mg·mL−1 (100 μM) and 4.96 mg·mL−1 (600 μM), respectively. Moreover, it was verified by NMR spectroscopy that the most promising POT, P5W30, remains intact under all the experimental conditions, after 24 h at 37 °C. This prompted us to further evaluate the anti-quorum sensing activity of P5W30 using the biosensor Chromobacterium violaceum CV026, as well as its antibiofilm activity both individually and in combination with the antibiotic cefoxitin against the methicillin-resistant Staphylococcus aureus 16 (MRSA16). P5W30 showed a synergistic antibacterial effect with the antibiotic cefoxitin and chloramphenicol against MRSA16. Moreover, the antibiofilm activity of P5W30 was more pronounced when used individually, in comparison with the combination with the antibiotic cefoxitin. Finally, the antiviral activity of P5W30 was tested using the coliphage Qβ, showing a dose-dependent response. The maximum inactivation was observed at 750 μM (6.23 mg·mL−1). In sum, P5W30 shows anti-quorum sensing and antibiofilm activities besides being a potent antibacterial agent against S. aureus and to exhibit antiviral activities against enteric viruses.
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Affiliation(s)
- Leonor Faleiro
- Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; (A.M.); (J.M.)
- Algarve Biomedical Center—Research Institute, 8005-139 Faro, Portugal
- Champalimaud Research Program, Champalimaud Centre for the Unknown, 1400-038 Lisbon, Portugal
- Correspondence: (L.F.); (M.A.)
| | - Ana Marques
- Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; (A.M.); (J.M.)
- Algarve Biomedical Center—Research Institute, 8005-139 Faro, Portugal
| | - João Martins
- Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; (A.M.); (J.M.)
- Centro de Ciências do Mar (CCMar), Universidade do Algarve, 8005-139 Faro, Portugal
| | - Luísa Jordão
- Departamento de Saúde Ambiental (DSA), Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA), Unidade de Investigação e Desenvolvimento, 1649-016 Lisboa, Portugal;
| | - Isabel Nogueira
- MicroLab, Instituto Superior Técnico, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal;
| | - Nadiia I. Gumerova
- Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, 1090 Wien, Austria; (N.I.G.); (A.R.)
| | - Annette Rompel
- Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, 1090 Wien, Austria; (N.I.G.); (A.R.)
| | - Manuel Aureliano
- Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; (A.M.); (J.M.)
- Centro de Ciências do Mar (CCMar), Universidade do Algarve, 8005-139 Faro, Portugal
- Correspondence: (L.F.); (M.A.)
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Lampl R, Breibeck J, Gumerova NI, Galanski MS, Rompel A. Wells-Dawson phosphotungstates as mushroom tyrosinase inhibitors: a speciation study. Sci Rep 2021; 11:19354. [PMID: 34588468 PMCID: PMC8481536 DOI: 10.1038/s41598-021-96491-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 08/06/2021] [Indexed: 01/28/2023] Open
Abstract
In order to elucidate the active polyoxotungstate (POT) species that inhibit fungal polyphenol oxidase (AbPPO4) in sodium citrate buffer at pH 6.8, four Wells-Dawson phosphotungstates [α/β-PV2WVI18O62]6- (intact form), [α2-PV2WVI17O61]10- (monolacunary), [PV2WVI15O56]12- (trilacunary) and [H2PV2WVI12O48]12- (hexalacunary) were investigated. The speciation of the POT solutions under the dopachrome assay (50 mM Na-citrate buffer, pH 6.8; L-3,4-dihydroxyphenylalanine as a substrate) conditions were determined by 183W-NMR, 31P-NMR spectroscopy and mass spectrometry. The intact Wells-Dawson POT [α/β-PV2WVI18O62]6- shows partial (~ 69%) disintegration into the monolacunary [α2-PV2WVI17O61]10- anion with moderate activity (Ki = 9.7 mM). The monolacunary [α2-PV2WVI17O61]10- retains its structural integrity and exhibits the strongest inhibition of AbPPO4 (Ki = 6.5 mM). The trilacunary POT [PV2WVI15O56]12- rearranges to the more stable monolacunary [α2-PV2WVI17O61]10- (~ 62%) accompanied by release of free phosphates and shows the weakest inhibition (Ki = 13.6 mM). The hexalacunary anion [H2PV2WVI12O48]12- undergoes time-dependent hydrolysis resulting in a mixture of [H2PV2WVI12O48]12-, [PV8WVI48O184]40-, [PV2WVI19O69(H2O)]14- and [α2-PV2WVI17O61]10- which together leads to comparable inhibitory activity (Ki = 7.5 mM) after 48 h. For the solutions of [α/β-PV2WVI18O62]6-, [α2-PV2WVI17O61]10- and [PV2WVI15O56]12- the inhibitory activity is correlated to the degree of their rearrangement to [α2-PV2WVI17O61]10-. The rearrangement of hexalacunary [H2PV2WVI12O48]12- into at least four POTs with a negligible amount of monolacunary anion interferes with the correlation of activity to the degree of their rearrangement to [α2-PV2WVI17O61]10-. The good inhibitory effect of the Wells-Dawson [α2-PV2WVI17O61]10- anion is explained by the low charge density of its protonated forms Hx[α2-PV2WVI17O61](10-x)- (x = 3 or 4) at pH 6.8.
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Affiliation(s)
- Raphael Lampl
- Fakultät für Chemie, Institut für Biophysikalische Chemie, Universität Wien, Althanstraße 14, 1090, Wien, Austria
| | - Joscha Breibeck
- Fakultät für Chemie, Institut für Biophysikalische Chemie, Universität Wien, Althanstraße 14, 1090, Wien, Austria
| | - Nadiia I Gumerova
- Fakultät für Chemie, Institut für Biophysikalische Chemie, Universität Wien, Althanstraße 14, 1090, Wien, Austria
| | - Mathea Sophia Galanski
- Fakultät für Chemie, Institut für Anorganische Chemie und NMR Zentrum, Universität Wien, Währinger Str. 42, 1090, Wien, Austria
| | - Annette Rompel
- Fakultät für Chemie, Institut für Biophysikalische Chemie, Universität Wien, Althanstraße 14, 1090, Wien, Austria.
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Pimpão C, da Silva IV, Mósca AF, Pinho JO, Gaspar MM, Gumerova NI, Rompel A, Aureliano M, Soveral G. The Aquaporin-3-Inhibiting Potential of Polyoxotungstates. Int J Mol Sci 2020; 21:E2467. [PMID: 32252345 PMCID: PMC7177757 DOI: 10.3390/ijms21072467] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 03/25/2020] [Accepted: 03/31/2020] [Indexed: 02/07/2023] Open
Abstract
Polyoxometalates (POMs) are of increasing interest due to their proven anticancer activities. Aquaporins (AQPs) were found to be overexpressed in tumors bringing particular attention to their inhibitors as anticancer drugs. Herein, we report for the first time the ability of polyoxotungstates (POTs), such as of Wells-Dawson P2W18, P2W12, and P2W15, and Preyssler P5W30 structures, to affect aquaporin-3 (AQP3) activity and impair melanoma cell migration. The tested POTs were revealed to inhibit AQP3 function with different effects, with P2W18, P2W12, and P5W30 being the most potent (50% inhibitory concentration (IC50) = 0.8, 2.8, and 3.2 µM), and P2W15 being the weakest (IC50 > 100 µM). The selectivity of P2W18 toward AQP3 was confirmed in yeast cells transformed with human aquaglyceroporins. The effect of P2W12 and P2W18 on melanoma cells that highly express AQP3 revealed an impairment of cell migration between 55% and 65% after 24 h, indicating that the anticancer properties of these compounds may in part be due to the blockage of AQP3-mediated permeability. Altogether, our data revealed that P2W18 strongly affects AQP3 activity and cancer cell growth, unveiling its potential as an anticancer drug against tumors where AQP3 is highly expressed.
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Affiliation(s)
- Catarina Pimpão
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal; (C.P.); (I.V.d.S.); (A.F.M.); (J.O.P.); (M.M.G.)
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal
| | - Inês V. da Silva
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal; (C.P.); (I.V.d.S.); (A.F.M.); (J.O.P.); (M.M.G.)
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal
| | - Andreia F. Mósca
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal; (C.P.); (I.V.d.S.); (A.F.M.); (J.O.P.); (M.M.G.)
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal
| | - Jacinta O. Pinho
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal; (C.P.); (I.V.d.S.); (A.F.M.); (J.O.P.); (M.M.G.)
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal
| | - Maria Manuela Gaspar
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal; (C.P.); (I.V.d.S.); (A.F.M.); (J.O.P.); (M.M.G.)
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal
| | - Nadiia I. Gumerova
- Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, 1090 Vienna, Austria; (N.I.G.); (A.R.)
| | - Annette Rompel
- Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, 1090 Vienna, Austria; (N.I.G.); (A.R.)
| | - Manuel Aureliano
- Faculdade de Ciências e Tecnologia (FCT), CCMar, Universidade do Algarve, 8005-139 Faro, Portugal
| | - Graça Soveral
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal; (C.P.); (I.V.d.S.); (A.F.M.); (J.O.P.); (M.M.G.)
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisbon, Portugal
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Self-Assembly in Polyoxometalate and Metal Coordination-Based Systems: Synthetic Approaches and Developments. INORGANICS 2018. [DOI: 10.3390/inorganics6030071] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Utilizing new experimental approaches and gradual understanding of the underlying chemical processes has led to advances in the self-assembly of inorganic and metal–organic compounds at a very fast pace over the last decades. Exploitation of unveiled information originating from initial experimental observations has sparked the development of new families of compounds with unique structural characteristics and functionalities. The main source of inspiration for numerous research groups originated from the implementation of the design element along with the discovery of new chemical components which can self-assemble into complex structures with wide range of sizes, topologies and functionalities. Not only do self-assembled inorganic and metal–organic chemical systems belong to families of compounds with configurable structures, but also have a vast array of physical properties which reflect the chemical information stored in the various “modular” molecular subunits. The purpose of this short review article is not the exhaustive discussion of the broad field of inorganic and metal–organic chemical systems, but the discussion of some representative examples from each category which demonstrate the implementation of new synthetic approaches and design principles.
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Zhang D, Zhang C, Ma P, Bassil BS, Al-Oweini R, Kortz U, Wang J, Niu J. Two new members of the niobium-substituted polytungstophosphate family based on hexalacunary [H2P2W12O48]12− building blocks. Inorg Chem Front 2015. [DOI: 10.1039/c4qi00169a] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Herein we present two structurally novel nanoscale clusters [{Nb6(O2)4P2W12O57}2]20− (1) and [{P2W12Nb7O63(H2O)2}4{Nb4O4(OH)6}]30− (2) formed by controlling the reaction parameters.
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Affiliation(s)
- Dongdi Zhang
- Key Laboratory of Polyoxometalate Chemistry of Henan Province
- Institute of Molecular and Crystal Engineering
- College of Chemistry and Chemical Engineering
- Henan University
- Kaifeng 475004
| | - Chao Zhang
- Collaborative Innovation Center of Chemistry for Energy Materials
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
- P. R. China
| | - Pengtao Ma
- Key Laboratory of Polyoxometalate Chemistry of Henan Province
- Institute of Molecular and Crystal Engineering
- College of Chemistry and Chemical Engineering
- Henan University
- Kaifeng 475004
| | - Bassem S. Bassil
- School of Engineering and Science
- Jacobs University
- 28725 Bremen
- Germany
- Department of Chemistry
| | - Rami Al-Oweini
- School of Engineering and Science
- Jacobs University
- 28725 Bremen
- Germany
- Department of Chemistry
| | - Ulrich Kortz
- School of Engineering and Science
- Jacobs University
- 28725 Bremen
- Germany
| | - Jingping Wang
- Key Laboratory of Polyoxometalate Chemistry of Henan Province
- Institute of Molecular and Crystal Engineering
- College of Chemistry and Chemical Engineering
- Henan University
- Kaifeng 475004
| | - Jingyang Niu
- Key Laboratory of Polyoxometalate Chemistry of Henan Province
- Institute of Molecular and Crystal Engineering
- College of Chemistry and Chemical Engineering
- Henan University
- Kaifeng 475004
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Laxson WW, Özkar S, Finke RG. Triniobium, Wells–Dawson-Type Polyoxoanion, [(n-C4H9)4N]9P2W15Nb3O62: Improvements in the Synthesis, Its Reliability, the Purity of the Product, and the Detailed Synthetic Procedure. Inorg Chem 2014; 53:2666-76. [DOI: 10.1021/ic403057k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- William W. Laxson
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Saim Özkar
- Department
of Chemistry, Middle East Technical University, 06800 Ankara, Turkey
| | - Richard G. Finke
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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Li CC, Liu SX, Li SJ, Yang Y, Jin HY, Ma FJ. Assembly of Saturated Nb/W Mixed-Addendum Polyoxometalate [P2W15Nb3O62]9- and Lanthanide Ions (Ln = Eu, Ce). Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201101347] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sakai Y, Shinohara A, Hayashi K, Nomiya K. Synthesis and Characterization of Two Novel, Mono-Lacunary Dawson Polyoxometalate-Based, Water-Soluble Organometallic Ruthenium(II) Complexes: Molecular Structure of [{(C6H6)Ru(H2O)}(α2-P2W17O61)]8-. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200500408] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sakai Y, Yoza K, Kato CN, Nomiya K. A first example of polyoxotungstate-based giant molecule. Synthesis and molecular structure of a tetrapod-shaped Ti–O–Ti bridged anhydride form of Dawson tri-titanium(iv)-substituted polyoxotungstate. Dalton Trans 2003. [DOI: 10.1039/b304033j] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hornstein BJ, Finke RG. The lacunary polyoxoanion synthon alpha-P(2)W(15)O(56)(12-): an investigation of the key variables in its synthesis plus multiple control reactions leading to a reliable synthesis. Inorg Chem 2002; 41:2720-30. [PMID: 12005496 DOI: 10.1021/ic020033a] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A reliable way to determine the purity of the kinetically precipitated, noncrystalline lacunary polyoxoanion alpha-P(2)W(15)O(56)(12-) has been developed, namely, the conversion of alpha-P(2)W(15)O(56)(12-) into the tri-Nb(5+)- and V(5+)-containing polyoxoanions P(2)W(15)Nb(3)O(62)(9-) and P(2)W(15)V(3)O(62)(9-), respectively, followed by quantitative analysis of their purity by (31)P-NMR prior to recrystallization. With this previously unappreciated, straightforward alpha-P(2)W(15)O(56)(12-) purity-assessment methodology in hand, the five reported literature syntheses of alpha-P(2)W(15)O(56)(12-) are investigated with an emphasis on understanding the effects of the five differing variables within these syntheses (the amount of Na(2)CO(3) base, the rate of addition of the base, the reaction temperature, the reaction scale, and the product drying method). Two methods of Nb(5+) addition (Nb(6)O(19)(8-) and NbCl(5)) to yield P(2)W(15)Nb(3)O(62)(9-) are also evaluated, as is the issue of whether any purification is provided by the normally optimum strategy of first preparing a water-soluble salt and its crystallization from water (here the (CH(3))(4)N(+) salt of the Nb-O-Nb bridged anhydride, P(4)W(30)Nb(6)O(123)(16-)), followed by its conversion to the organic-solvent soluble, but noncrystalline, (n-C(4)H(9))(4)N(+) salt, [(n-C(4)H(9))(4)N](9)[P(2)W(15)Nb(3)O(62)]. The results yield five previously unavailable and unequivocal insights: (1) Only the amount of added Na(2)CO(3) base affects the purity or yield of the desired alpha-P(2)W(15)O(56)(12-); the amount of added base is key, however. (2) Contant's 1990 Inorganic Syntheses procedure provides the highest-purity alpha-P(2)W(15)O(56)(12-) presently available. (3) All prior syntheses calling for the addition of base to P(2)W(18)O(62)(6-) until pH 9 must be abandoned. (4) The purity of even Contant's alpha-P(2)W(15)O(56)(12-) is only 90%. (5) An identifiable impurity is the 16 tungsten polyoxoanion, alpha-P(2)W(16)()O(59)(12-). Also identified and summarized are multiple compounding errors in the observation of, reporting on, and thinking about the synthesis of alpha-P(2)W(15)O(56)(12-) historically, errors which delayed the most reliable synthesis of alpha-P(2)W(15)O(56)(12-) from being identified for 18 years (from the 1983 discovery of alpha-P(2)W(15)O(56)(12-)). However, these errors yield valuable take-home lessons for anyone interested in working in this demanding area of inorganic synthetic chemistry, where direct structural methods for identifying the products and their purity, such as the lacunary polyoxoanion synthon alpha-P(2)W(15)O(56)(12-), sometimes simply do not exist.
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Affiliation(s)
- Brooks J Hornstein
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
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Nomiya K, Takahashi M, Widegren JA, Aizawa T, Sakai Y, Kasuga NC. Synthesis and pH-variable ultracentrifugation molecular weight measurements of the dimeric, Ti–O–Ti bridged anhydride form of a novel di-TiIV-1,2-substituted α-Keggin polyoxotungstate. Molecular structure of the [(α-1,2-PW10Ti2O39)2]10−polyoxoanion. ACTA ACUST UNITED AC 2002. [DOI: 10.1039/b204775f] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Nomiya K, Hasegawa T, Noguchi R, Nomura KI, Takahashi M, Yokoyama H. Synthesis, Characterization and Crystal Structure of the Water-Soluble, All-Inorganic Composition, A,β-Keggin Triniobium(V)-Substituted Polyoxotungstate. CHEM LETT 2001. [DOI: 10.1246/cl.2001.1278] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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14
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Nomiya* K, Arai Y, Shimizu Y, Takahashi M, Takayama T, Weiner H, Nagata T, Widegren JA, Finke* RG. Synthesis and characterization of the tetrameric, tri-titanium(IV)-substituted Wells–Dawson-substructure polyoxotungstate, [(P2W15Ti3O60.5)4]36−: the significance of ultracentrifugation molecular weight measurements in detecting aggregated, anhydride forms of polyoxoanions. Inorganica Chim Acta 2000. [DOI: 10.1016/s0020-1693(99)00603-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Nomiya K, Ohsawa K, Taguchi T, Kaneko M, Takayama T. Synthesis and Characterization of the Water-Soluble, All-Inorganic Composition, Keggin-Type Triniobium(V)-Substituted SiW9Nb3O407−Heteropolyoxoanions with Alkali Metal Countercations (Li+, Na+, K+, and Cs+). BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1998. [DOI: 10.1246/bcsj.71.2603] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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16
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Nomiya K, Nozaki C, Miyazawa K, Shimizu Y, Takayama T, Nomura K. Synthesis and Characterization of Water-Soluble, All-Inorganic Composition, Dawson-Type Trisubstituted Heteropolytungstates. Effect of Alkali Metal Countercations (Li, Na, K, and Cs) on the P2W15Nb3O629−Polyoxoanion. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1997. [DOI: 10.1246/bcsj.70.1369] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Syntheses and characterization of the heptasodium salt of the Keggin-type triniobium-substituted polyoxoanion SiW9Nb3O7−40 and the all-sodium salt of the polyoxoanion-supported organometallic complex [(η5-C5Me5)Rh·SiW9Nb3O40]5−. J Organomet Chem 1997. [DOI: 10.1016/s0022-328x(96)06828-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Stability and acidity contributions of heteropolymetalates: a theoretical study of the Keggin and Dawson ions. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0968-5677(96)00058-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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