Oxygen-Isotope Exchange Rates for Three Isostructural Polyoxometalate Ions

Villa, Eric M.; Ohlin, C. André; Casey, William H.

doi:10.1021/ja100490n

Cited by 59 publications

(60 citation statements)

References 39 publications

(82 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another concern is the potential exchange between 18 O and 16 O in nucleic acids following DNA replication or RNA transcription. For example, it is fairly well documented that oxygen isotope exchange can occur between water and a variety of substances, including metal complexes (36,53), organic matter (55), and monosaccharides such as ribose and deoxyribose (7), but the extent of this phenomenon for nucleic acids remains unclear. If a significant amount of isotopic exchange occurs between nucleic acids and cytoplasmic or extracellular water, then it could be problematic to associate microbial taxa with metabolic processes by using H 2 18 O-SIP.…”

mentioning

confidence: 99%

Validation of Heavy-Water Stable Isotope Probing for the Characterization of Rapidly Responding Soil Bacteria

Aanderud

Lennon

2011

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

mentioning

confidence: 99%

Validation of Heavy-Water Stable Isotope Probing for the Characterization of Rapidly Responding Soil Bacteria

Aanderud

Lennon

2011

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…It was used, for example, to follow the conversion of several niobates in water [66,67]. However, coordination of organometallic fragments to niobates and tantalates provides new opportunities for use of NMR for solution studies.…”

Section: Analytical Tools To Study Solution Speciation In Nb and Ta Pmentioning

confidence: 99%

Polyoxoniobates and Polyoxotantalates as Ligands—Revisited

2015

View full text Add to dashboard Cite

show abstract

“…The slow rates of dissociation of the molecule could be independently measured and exhibit the same pH variation as the steady oxygen-isotope exchanges. [96,97,[99][100][101]116] Decametalate anions A second series of anionic molecules can show how oxide reactivity, at least for oxygen-isotopic exchanges, is affected by protonation. The decaniobate [H x Nb 10 O 28 ] (6Àx)À ion (Fig.…”

Section: Rate Of Dissociationmentioning

confidence: 99%

“…The decaniobate [H x Nb 10 O 28 ] (6Àx)À ion (Fig. 1, bottom) has seven structurally distinct oxygens in D 2v symmetry that react so slowly that oxygen-isotope exchanges can be followed at each site using 17 O NMR spectroscopy [96][97][98][99][100][101] 17 O so that decreases in the 17 O NMR signal from each structural oxygen can be used to gauge rates of isotopic equilibration of that oxygen apart from all others in the structure.…”

Section: Rate Of Dissociationmentioning

confidence: 99%

Ligand- and oxygen-isotope-exchange pathways of geochemical interest

Casey¹

2015

Environ. Chem.

Self Cite

View full text Add to dashboard Cite

Environmental context. Most chemical processes in water are either ligand-or electron-exchange reactions.Here the general reactivity trends for ligand-exchange reactions in aqueous solutions are reviewed and it is shown that simple rules dominate the chemistry. These simple rules shed light on most molecular processes in water, including the uptake and degradation of pesticides, the sequestration of toxic metals and the corrosion of minerals.Abstract. It is through ligand-exchange kinetics that environmental geochemists establish an understanding of molecular processes, particularly for insulating oxides where there are not explicit electron exchanges. The substitution of ligands for terminal functional groups is relatively insensitive to small changes in structure but are sensitive to bond strengths and acid-base chemistry. Ligand exchanges involving chelating organic molecules are separable into two classes: (i) ligand substitutions that are enhanced by the presence of the chelating ligand, called a 'spectator' ligand and (ii) chelation reactions themselves, which are controlled by the Lewis basicity of the attacking functional group and the rates of ring closure. In contrast to this relatively simple chemistry at terminal functional groups, substitutions at bridging oxygens are exquisitely sensitive to details of structure. Included in this class are oxygen-isotope exchange and mineraldissolution reactions. In large nanometer-sized ions, metastable structures form as intermediates by detachment of a surface metal atom, often from a underlying, highly coordinated oxygen, such as m 4 -oxo, by solvation forces. A metastable equilibrium is then established by concerted motion of many atoms in the structure. The newly undercoordinated metal in the intermediate adds a water or ligand from solution, and protons transfer to other oxygens in the metastable structure, giving rise to a characteristic broad amphoteric chemistry. These metastable structures have an appreciable lifetime and require charge separation, which is why counterions affect the rates. The number and character of these intermediate structures reflect the symmetry of the starting structure. Simple reactivity trends for ligand-and oxygen-isotope exchanges FormalismMost metals in aqueous solutions of interest to environmental chemists are coordinatively saturated. Here saturated is meant in the sense of Pauling's First Rule, relating ionic radius to oxygen packing. Most metals in water have the maximum number of coordinated atoms given by their radius ratios -exceptions certainly exist for highly covalent materials (e.g. Pt II , Nb V ), and some are discussed below, but most materials near the Earth's surface are oxides with a metal that has a fixed coordination or slightly variable number. In sharp contrast, the coordination

show abstract

Oxygen-Isotope Exchange Rates for Three Isostructural Polyoxometalate Ions

Cited by 59 publications

References 39 publications

Validation of Heavy-Water Stable Isotope Probing for the Characterization of Rapidly Responding Soil Bacteria

Validation of Heavy-Water Stable Isotope Probing for the Characterization of Rapidly Responding Soil Bacteria

Polyoxoniobates and Polyoxotantalates as Ligands—Revisited

Ligand- and oxygen-isotope-exchange pathways of geochemical interest

Contact Info

Product

Resources

About