Quantum chemistry benchmarking of binding and selectivity for lanthanide extractants

International Journal of Quantum Chemistry

4 years ago

Quantum chemistry benchmarking of binding and selectivity for lanthanide extractants

John A. Keith, Minh Nguyen Vo, J. Karl Johnson, Vyacheslav S. Bryantsev

Computer-aided screening methods facilitate the discovery of new extractants for heavy and rare-earth metal separations. In this work, we have benchmarked the accuracy of different quantum chemistry methods for calculating extractant binding energies and selectivities. Specifically, we compare calculated data from different exchange correlation functionals (B3LYP-D3, ωB97X-D3, and M06-L) and different basis sets (including large-core effective core potentials and all-electron basis sets). We report aqueous-phase binding energy and selectivity trends for 1:1 and 3:1 extractant/lanthanide models for the complexes. We find that binding selectivities are not particularly sensitive to model chemistry, but binding energies are sensitive. Furthermore, calculated trends in selectivity using 3:1 extractant/lanthanide models are in better agreement with available experimental trends than trends using 1:1 extractant/lanthanide models. Lastly, we find that the B3LYP-D3/6-31 + G* model chemistry with the Stuttgart large-core relativistic effective core potentials on the lanthanide sufficiently reproduces results from larger basis set calculations and is confirmed as suitable for relatively fast and efficient screening of lanthanide binding energies and selectivities. Quantum computational modeling can advance the discovery of novel extractant for effective adjacent lanthanide separation. The accuracy of different first-principles methods, specifically exchange correlation density functionals and basis sets, for calculating extractant binding energies and selectivities is benchmarked. This study compares the use 1:1 and 3:1 extractant/lanthanide complex models to predict aqueous binding energies and selectivity trends for lanthanides.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/qua.25516