Combining luminescence spectroscopy, parallel factor analysis and quantum chemistry to reveal metal speciation – a case study of uranyl(vi) hydrolysis

Abstract

The sensitive excitation of uranyl(vi) hydrolysis species in the UV (180 to 370 nm) is due to ligand-to-metal charge transfer.

pH‐dependent speciation and hydrogen (H2) control U(VI) respiration by Desulfovibrio vulgaris

“…Cytochrome c3 has a mid-point redox potential near −300 mV versus SHE (standard hydrogen electrode) at 25°C (Niki et al, 1984), while the U(VI)-U(IV) couple has a mid-point potential of +334 mV versus SHE of dissolved inorganic carbon (DIC) and with a wide range of pH is of paramount importance for understanding microbial reduction of U(VI), since different U(VI) species could have different susceptibilities of being reduced based on their bioavailability. A decrease in U(VI) reduction rate with increasing DIC concentration, along with sensitivity towards pH, has been well documented in the literature (Belli et al, 2015;Bernhard, Geipel, Brendler, & Nitsche, 1998;Brooks et al, 2003;Croteau, Fuller, Cain, Campbell, & Aiken, 2016;Drobot et al, 2015;Guillauont et al, 2003;Jones et al, 2015;Sheng & Fein, 2014;Ulrich et al, 2011).…”

“…The conventional thinking is that free UO 2 2+ and its mono-nuclear complexes with hydroxides and carbonates are bioavailable to microorganisms (Tutem, Apak, Turgut, & Apak, 1991). Poly-nuclear complexes are known to have lesser cell permeability and, hence, may have lower bioavailability (Bernhard et al, 1998;Croteau et al, 2016;Drobot et al, 2015;Guillauont et al, 2003;Jones et al, 2015;Kulkarni, Misra, Gupta, Ballal, & Apte, 2016). In addition, adsorption of U(VI) to colloidal or particulate ligands should render it even less bioavailable (Du et al, 2011).…”

Quantum chemical calculations and spectroscopic measurements of spectroscopic and thermodynamic properties of given uranyl complexes in aqueous solutions with possible environmental and industrial applications

“…Later, we have found that a similar approach was used for uranyl hydroxo-complexes by Drobot et al [106]. We also look for quantum chemistry to interpret the experimental results.…”

A Structural and Spectroscopic Study of the First Uranyl Selenocyanate, [Et4N]3[UO2(NCSe)5]

“…Visible on the absorption and emission bands are the vibronic progression arising from strong coupling of the ground state Raman active symmetric vibrational O=U=O (ν 1 ) mode with the 3 Π u electronic triplet excited state. Time resolved studies allow sometimes complex speciation in water to be deconvoluted [7], whilst in non-aqueous media the positions of the emission maxima and lifetimes can be used as electronic and structural probes. For instance in the family of complexes trans-[UO 2 X 2 (O=PPh 3 ) 2 ] (X = Cl, Br, I) the photoluminescent properties do not vary [8], but for the compounds trans-[UO 2 Cl 2 L 2 ] (L = Ph 3 P=NH, Ph 3 P=O and Ph 3 As=O) a red shift in the O yl ÑU LMCT band is observed, in line with the increased donor strength of the ligand [9].…”