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Quantum Chemistry Study on the Extraction of Trivalent Lanthanide Series by Cyanex301: Insights from Formation of Inner- and Outer-Sphere Complexes

[Image: see text] The extraction of lanthanide series by Cyanex301, i.e., bis(2,4,4-trimethylpentyl)dithiophosphinic acid (HC301), has been modeled by density functional theory calculation, taking into account the formation of both inner- and outer-sphere complexes. The inner-sphere complex Ln(C301)...

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Autores principales: Sun, Taoxiang, Xu, Chao, Xie, Xiaofeng, Chen, Jing, Liu, Xuegang
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2018
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6641625/
https://www.ncbi.nlm.nih.gov/pubmed/31458643
http://dx.doi.org/10.1021/acsomega.8b00359
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author Sun, Taoxiang
Xu, Chao
Xie, Xiaofeng
Chen, Jing
Liu, Xuegang
author_facet Sun, Taoxiang
Xu, Chao
Xie, Xiaofeng
Chen, Jing
Liu, Xuegang
author_sort Sun, Taoxiang
collection PubMed
description [Image: see text] The extraction of lanthanide series by Cyanex301, i.e., bis(2,4,4-trimethylpentyl)dithiophosphinic acid (HC301), has been modeled by density functional theory calculation, taking into account the formation of both inner- and outer-sphere complexes. The inner-sphere complex Ln(C301)(3) and the outer-sphere complex Ln(H(2)O)(9)(C301)(3) are optimized, followed by the analysis of interaction energy, bond length, Laplacian bond orders, and Mulliken populations. The covalency degree increases in Ln–S and Ln–O bonds in the inner- and outer-sphere complexes, respectively, as the lanthanide series is traversed. Mulliken population analysis indicates the important role of the 5d-orbital participation in bonding in the formation of inner- and outer-sphere complexes. Two thermodynamic cycles regarding the formation of inner- and outer-sphere complexes are established to calculate the extraction Gibbs free energies (ΔG(extr)), and relaxed potential energy surface scan is utilized to model the kinetic complexation of C301 anion with hydrated metal ions. Light lanthanides can form both inner- and outer-sphere complexes, whereas heavy lanthanides only form outer-sphere complexes in biphasic extraction. After adopting the data of forming inner-sphere complex for light Ln(III) and that of forming outer-sphere complexes for heavy Ln(III), the trend of the calculated −ΔG(extr) agrees very well with that of the experimental distribution ratios on crossing the Ln(III) series. Results from this work help to theoretically understand the extraction behavior of Cyanex301 with respect to different Ln(III).
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spelling pubmed-66416252019-08-27 Quantum Chemistry Study on the Extraction of Trivalent Lanthanide Series by Cyanex301: Insights from Formation of Inner- and Outer-Sphere Complexes Sun, Taoxiang Xu, Chao Xie, Xiaofeng Chen, Jing Liu, Xuegang ACS Omega [Image: see text] The extraction of lanthanide series by Cyanex301, i.e., bis(2,4,4-trimethylpentyl)dithiophosphinic acid (HC301), has been modeled by density functional theory calculation, taking into account the formation of both inner- and outer-sphere complexes. The inner-sphere complex Ln(C301)(3) and the outer-sphere complex Ln(H(2)O)(9)(C301)(3) are optimized, followed by the analysis of interaction energy, bond length, Laplacian bond orders, and Mulliken populations. The covalency degree increases in Ln–S and Ln–O bonds in the inner- and outer-sphere complexes, respectively, as the lanthanide series is traversed. Mulliken population analysis indicates the important role of the 5d-orbital participation in bonding in the formation of inner- and outer-sphere complexes. Two thermodynamic cycles regarding the formation of inner- and outer-sphere complexes are established to calculate the extraction Gibbs free energies (ΔG(extr)), and relaxed potential energy surface scan is utilized to model the kinetic complexation of C301 anion with hydrated metal ions. Light lanthanides can form both inner- and outer-sphere complexes, whereas heavy lanthanides only form outer-sphere complexes in biphasic extraction. After adopting the data of forming inner-sphere complex for light Ln(III) and that of forming outer-sphere complexes for heavy Ln(III), the trend of the calculated −ΔG(extr) agrees very well with that of the experimental distribution ratios on crossing the Ln(III) series. Results from this work help to theoretically understand the extraction behavior of Cyanex301 with respect to different Ln(III). American Chemical Society 2018-04-11 /pmc/articles/PMC6641625/ /pubmed/31458643 http://dx.doi.org/10.1021/acsomega.8b00359 Text en Copyright © 2018 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
spellingShingle Sun, Taoxiang
Xu, Chao
Xie, Xiaofeng
Chen, Jing
Liu, Xuegang
Quantum Chemistry Study on the Extraction of Trivalent Lanthanide Series by Cyanex301: Insights from Formation of Inner- and Outer-Sphere Complexes
title Quantum Chemistry Study on the Extraction of Trivalent Lanthanide Series by Cyanex301: Insights from Formation of Inner- and Outer-Sphere Complexes
title_full Quantum Chemistry Study on the Extraction of Trivalent Lanthanide Series by Cyanex301: Insights from Formation of Inner- and Outer-Sphere Complexes
title_fullStr Quantum Chemistry Study on the Extraction of Trivalent Lanthanide Series by Cyanex301: Insights from Formation of Inner- and Outer-Sphere Complexes
title_full_unstemmed Quantum Chemistry Study on the Extraction of Trivalent Lanthanide Series by Cyanex301: Insights from Formation of Inner- and Outer-Sphere Complexes
title_short Quantum Chemistry Study on the Extraction of Trivalent Lanthanide Series by Cyanex301: Insights from Formation of Inner- and Outer-Sphere Complexes
title_sort quantum chemistry study on the extraction of trivalent lanthanide series by cyanex301: insights from formation of inner- and outer-sphere complexes
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6641625/
https://www.ncbi.nlm.nih.gov/pubmed/31458643
http://dx.doi.org/10.1021/acsomega.8b00359
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