Size and shape trump charge in interactions of oxovanadates with self-assembled interfaces: application of continuous shape measure analysis to the decavanadate anion

Sánchez-Lombardo, Irma; Baruah, Bharat; Álvarez, Santiago; Werst, Katarina R.; Segaline, Nicole; Levinger, Nancy E.; Crans, Debbie C.

doi:10.1039/c5nj01788b

Cited by 17 publications

(17 citation statements)

References 166 publications

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“…The former (Figure S1) is consistent with previously reported results. 16 While the sharp feature at ∼1550 cm −1 is due to the ammonium counterion and the broad high-energy features are due to at least one O−H stretch (indicating protonation of one of the POM's exterior oxo ligands), the many overlapping features in the so-called "fingerprint region" cannot be assigned on the basis of this spectrum alone. Thus, we analyzed it alongside the rR spectrum in the 200−1200 cm −1 range (Figure 2).…”

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confidence: 61%

Features of Vibrational and Electronic Structures of Decavanadate Revealed by Resonance Raman Spectroscopy and Density Functional Theory

Avila

Ripplinger

Kemper

et al. 2019

J. Phys. Chem. Lett.

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Polyoxometalates are known to be inhibitors of a diverse collection of enzymes, although the specific interactions that lead to this bioactivity are still unclear. Spectroscopic characterization may be an invaluable if indirect tool for remedying this problem, yet this requires clear, cogent assignment of polyoxometalate spectra before the complicating effect of their binding to large biomolecules can be considered. We report the use of FT-IR and resonance Raman spectroscopies alongside density functional theory to describe the vibrational and electronic structures of decavanadate, [V10O28]6–. Our computational model, which reproduced the majority of vibrational features to within 10 cm–1, was used to identify an axial oxo ligand as the most likely position of the acidic proton in the related cluster [HV10O28]5–. As resonance Raman spectroscopy can directly interrogate chromophores embedded in complex systems, this approach may be of general use in answering structural questions about polyoxometalate–enzyme systems.

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confidence: 61%

Features of Vibrational and Electronic Structures of Decavanadate Revealed by Resonance Raman Spectroscopy and Density Functional Theory

Avila

Ripplinger

Kemper

et al. 2019

J. Phys. Chem. Lett.

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“…The concentrations of each vanadate species V x were calculated from the fractions of the total integrated areas using the following equation: [V x ] = (A x /A t ) × ([V t ]/n), where A x corresponds to the area measured for the x vanadate species with n as the oligomer number (number of vanadium atoms), A t is the sum of the measured areas and [V t ] is the total vanadate concentration [71]. In the case of the decameric species, three signals at −420, −494 and −510 ppm were integrated for 2, 4 and 4 vanadium atoms, respectively [72].…”

Section: Kinetic Studiesmentioning

confidence: 99%

Kinetic Studies of Sodium and Metforminium Decavanadates Decomposition and In Vitro Cytotoxicity and Insulin- Like Activity

et al. 2020

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The kinetics of the decomposition of 0.5 and 1.0 mM sodium decavanadate (NaDeca) and metforminium decavanadate (MetfDeca) solutions were studied by 51V NMR in Dulbecco’s modified Eagle’s medium (DMEM) medium (pH 7.4) at 25 °C. The results showed that decomposition products are orthovanadate [H2VO4]− (V1) and metavanadate species like [H2V2O7]2− (V2), [V4O12]4− (V4) and [V5O15]5− (V5) for both compounds. The calculated half-life times of the decomposition reaction were 9 and 11 h for NaDeca and MetfDeca, respectively, at 1 mM concentration. The hydrolysis products that presented the highest rate constants were V1 and V4 for both compounds. Cytotoxic activity studies using non-tumorigenic HEK293 cell line and human liver cancer HEPG2 cells showed that decavanadates compounds exhibit selectivity action toward HEPG2 cells after 24 h. The effect of vanadium compounds (8–30 μM concentration) on the protein expression of AKT and AMPK were investigated in HEPG2 cell lines, showing that NaDeca and MetfDeca compounds exhibit a dose-dependence increase in phosphorylated AKT. Additionally, NaDeca at 30 µM concentration stimulated the glucose cell uptake moderately (62%) in 3T3-L1 adipocytes. Finally, an insulin release assay in βTC-6 cells (30 µM concentration) showed that sodium orthovanadate (MetV) and MetfDeca enhanced insulin release by 0.7 and 1-fold, respectively.

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“…This size allowed for a V 10 molecule and a layer of 2–3 water molecules inside the water droplet. We also showed that a V 10 with a Mo [ 51 ] replacing one of the V-atoms, V 9 Mo, with similar shape but at a different charge behave similarly to V 10 [ 50 , 51 ]. These compounds are placed in the center of the water pool, however, we found that cations could change the system significantly [ 52 ].…”

Section: Resultsmentioning

confidence: 87%

Confinement Effects on Chemical Equilibria: Pentacyano(Pyrazine)Ferrate(II) Stability Changes within Nanosized Droplets of Water

et al. 2018

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Nanoscale confinement is known to impact properties of molecules and we observed changes in the reactivity of an iron coordination complex, pentacyano(pyrazine)ferrate(II). The confinement of two coordination complexes in a sodium AOT/isooctane reverse micellar (RM) water droplet was found to dramatically increase the hydrolysis rate of [Fe(CN)5pyz]3− and change the monomer-dimer equilibria between [Fe(CN)5pyz]3− and [Fe2(CN)10pyz]6−. Combined UV-Vis and 1H-NMR spectra of these complexes in RMs were analyzed and the position of the monomer-dimer equilibrium and the relative reaction times were determined at three different RM sizes. The data show that the hydrolysis rates (loss of pyrazine) are dramatically enhanced in RMs over bulk water and increase as the size of the RM decreases. Likewise, the monomer-dimer equilibrium changes to favor the formation of dimer as the RM size decreases. We conclude that the effects of the [Fe(CN)5pyz]3− stability is related to its solvation within the RM.

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Size and shape trump charge in interactions of oxovanadates with self-assembled interfaces: application of continuous shape measure analysis to the decavanadate anion

Abstract: Using 51V NMR spectroscopy, dynamic light scattering and continuous shape analysis to characterize two polyoxometalate-encapsulation in reverse micelles.

Cited by 17 publications

References 166 publications

Features of Vibrational and Electronic Structures of Decavanadate Revealed by Resonance Raman Spectroscopy and Density Functional Theory

Features of Vibrational and Electronic Structures of Decavanadate Revealed by Resonance Raman Spectroscopy and Density Functional Theory

Kinetic Studies of Sodium and Metforminium Decavanadates Decomposition and In Vitro Cytotoxicity and Insulin- Like Activity

Confinement Effects on Chemical Equilibria: Pentacyano(Pyrazine)Ferrate(II) Stability Changes within Nanosized Droplets of Water

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