Oxygen exchange in uranyl hydroxide via two "nonclassical" ions
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A recently proposed pathway for the scrambling of axial (uranyl) and equatorial 0 atoms in [UO2(OH)4]2- (1) is refined using Car-Parrinello molecular dynamics (CPMD) simulations in an explicit solvent (water) and with model counterions (NH4+). According to constrained CPMD/BLYP simulations and thermodynamic integration, 1 can be deprotonated to [UO3(OH)3]3- with a T-shaped UO3 group (Delta A = 7.1 kcal/mol), which in turn can undergo a solvent-assisted proton transfer via a cis-[UO2(OH)4]2-center dot OH- complex and a total overall barrier of Delta A(double dagger) = 12.5 kcal/mol. According to computed relative energies of trans- and cis-[UO2(OH)4]2- in the gas phase and in a polarizable continuum, "pure" functionals such as BLYP underestimate this overall barrier somewhat, and estimates of Delta A(double dagger) approximate to 16 and 17 kcal/mol are obtained at the B3LYP and CCSD(T) levels, respectively, in excellent agreement with the experiment.
Buehl , M & Schreckenbach , G 2010 , ' Oxygen exchange in uranyl hydroxide via two "nonclassical" ions ' Inorganic Chemistry , vol 49 , no. 8 , pp. 3821-3827 . , 10.1021/ic902508z
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society, after peer review and technical editing by the publisher. To access the final edited and published work see DOI: 10.1021/ic902508z
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