Rates of Oxygen Exchange between the [H_xNb₆O₁₉]^8-x_(aq) Lindqvist Ion and Aqueous Solutions [J. Am. Chem. Soc. 2006, 128, 14712−14720].

Abstract

Page 13107, Figure 3. The reported isotope effect 18 k bridge for hydrolysis of the monoanion of mNBP is in error; the correct value is 1.0157 ( 0.0009. For comparison, 18 k bridge for pNPP monoanion hydrolysis is 1.0087. Since the maximum 18 k bridge for the alkyl leaving group mNBP is expected to be about twice 1 that for the aryl leaving group in pNPP, the KIEs for the two monoanion reactions are similar in proportion to their respective upper limits. This indicates a similar extent of P-O bond fission in the two reactions. The other data reported in the paper are unaffected. The major conclusion, that the data are most consistent with a pre-equilibrium proton transfer followed by rate-determining P-O bond fission for both pNPP and mNBP, is unchanged.

17O NMR chemical shifts in oxometalates: from the simplest monometallic species to mixed-metal polyoxometalates

“…80 In other cases, positions can be proposed based on 17 O NMR spectra. 25,[80][81][82][83][84] Computationally, this subject has been 50 tackled by many authors. [85][86][87][88][89] To analyze the effect of protonation on 17 O NMR of POMs, we focus on the well characterized decavanadate [V 10 O 28 ] 6anion, represented in Figure 7, since it features seven structural oxygen sites, six of which are external and could potentially be protonated.…”

Soluble Complexes of Cobalt Oxide Fragments Bring the Unique CO2 Photoreduction Activity of a Bulk Material into the Flexible Domain of Molecular Science

“…This is demonstrated by using six hexaniobate, − [Nb 6 O 19 ] 8– , cluster anions to encapsulate mixed-valent cobalt oxide cores comprising 13 Co atoms which, arising from partial occupancies at specific positions, closely match the mixed-valent structures of cubic-spinel and monoclinic Co 3 O 4 . The complex, 1 , was then used in place of bulk cobalt oxide as a cocatalyst for the direct Z-scheme reduction of CO 2 by solar light and water.…”

Reaction Mechanism of Nerve-Agent Hydrolysis with the Cs8Nb6O19 Lindqvist Hexaniobate Catalyst

“…Of the wealth of POM catalysts that have been synthesized over decades, − Group-V POMs with Lindqvist ion structure, particularly Nb 6 O 19 8– , are ideal candidates to act as base hydrolysis catalysts due to the high charge density of the exposed oxygen atoms . It is therefore not surprising that alkali salts of the Nb 6 O 19 8– ion have recently been reported to hydrolyze nerve agents. , Computational work on Nb 6 O 19 8– has included structural studies using DFT methods, the proposal (also with DFT methods) of an open-cage intermediate that leads to oxygen exchange with solvent measured with NMR, and a recent molecular dynamics study of the protonation of Nb 6 O 19 8– in aqueous media . However, no mechanistic studies of the base hydrolysis reactions with Nb 6 O 19 8– have been reported yet.…”