Assessing the performance of approximate density functional theory on 95 experimentally characterized Fe(II) spin crossover complexes

Spin crossover (SCO) complexes, which exhibit changes in spin state in response to external stimuli, have applications in molecular electronics and are challenging materials for computational design. We curate a dataset of 95 Fe(II) SCO complexes (SCO-95) from the Cambridge Structural Database that...

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Main Authors: Vennelakanti, Vyshnavi, Taylor, Michael G, Nandy, Aditya, Duan, Chenru, Kulik, Heather J
Other Authors: Massachusetts Institute of Technology. Department of Chemical Engineering
Format: Article
Language:English
Published: AIP Publishing 2024
Online Access:https://hdl.handle.net/1721.1/156892
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author Vennelakanti, Vyshnavi
Taylor, Michael G
Nandy, Aditya
Duan, Chenru
Kulik, Heather J
author2 Massachusetts Institute of Technology. Department of Chemical Engineering
author_facet Massachusetts Institute of Technology. Department of Chemical Engineering
Vennelakanti, Vyshnavi
Taylor, Michael G
Nandy, Aditya
Duan, Chenru
Kulik, Heather J
author_sort Vennelakanti, Vyshnavi
collection MIT
description Spin crossover (SCO) complexes, which exhibit changes in spin state in response to external stimuli, have applications in molecular electronics and are challenging materials for computational design. We curate a dataset of 95 Fe(II) SCO complexes (SCO-95) from the Cambridge Structural Database that have available low- and high-temperature crystal structures and, in most cases, confirmed experimental spin transition temperatures (T1/2). We study these complexes using density functional theory (DFT) with 30 functionals spanning across multiple rungs of “Jacob’s ladder” to understand the effect of exchange–correlation functional on electronic and Gibbs free energies associated with spin crossover. We specifically assess the effect of varying the Hartree–Fock exchange fraction (aHF) in structures and properties within the B3LYP family of functionals. We identify three best-performing functionals, a modified version of B3LYP (aHF = 0.10), M06-L, and TPSSh, that accurately predict SCO behavior for the majority of the complexes. While M06-L performs well, MN15-L, a more recently developed Minnesota functional, fails to predict SCO behavior for all complexes, which could be the result of differences in datasets used for parametrization of M06-L and MN15-L and also the increased number of parameters for MN15-L. Contrary to observations from prior studies, double-hybrids with higher aHF values are found to strongly stabilize high-spin states and therefore exhibit poor performance in predicting SCO behavior. Computationally predicted T1/2 values are consistent among the three functionals but show limited correlation to experimentally reported T1/2 values. These failures are attributed to the lack of crystal packing effects and counter-anions in the DFT calculations that would be needed to account for phenomena such as hysteresis and two-step SCO behavior. The SCO-95 set thus presents opportunities for method development, both in terms of increasing model complexity and method fidelity.
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spelling mit-1721.1/1568922024-12-23T05:47:24Z Assessing the performance of approximate density functional theory on 95 experimentally characterized Fe(II) spin crossover complexes Vennelakanti, Vyshnavi Taylor, Michael G Nandy, Aditya Duan, Chenru Kulik, Heather J Massachusetts Institute of Technology. Department of Chemical Engineering Massachusetts Institute of Technology. Department of Chemistry Spin crossover (SCO) complexes, which exhibit changes in spin state in response to external stimuli, have applications in molecular electronics and are challenging materials for computational design. We curate a dataset of 95 Fe(II) SCO complexes (SCO-95) from the Cambridge Structural Database that have available low- and high-temperature crystal structures and, in most cases, confirmed experimental spin transition temperatures (T1/2). We study these complexes using density functional theory (DFT) with 30 functionals spanning across multiple rungs of “Jacob’s ladder” to understand the effect of exchange–correlation functional on electronic and Gibbs free energies associated with spin crossover. We specifically assess the effect of varying the Hartree–Fock exchange fraction (aHF) in structures and properties within the B3LYP family of functionals. We identify three best-performing functionals, a modified version of B3LYP (aHF = 0.10), M06-L, and TPSSh, that accurately predict SCO behavior for the majority of the complexes. While M06-L performs well, MN15-L, a more recently developed Minnesota functional, fails to predict SCO behavior for all complexes, which could be the result of differences in datasets used for parametrization of M06-L and MN15-L and also the increased number of parameters for MN15-L. Contrary to observations from prior studies, double-hybrids with higher aHF values are found to strongly stabilize high-spin states and therefore exhibit poor performance in predicting SCO behavior. Computationally predicted T1/2 values are consistent among the three functionals but show limited correlation to experimentally reported T1/2 values. These failures are attributed to the lack of crystal packing effects and counter-anions in the DFT calculations that would be needed to account for phenomena such as hysteresis and two-step SCO behavior. The SCO-95 set thus presents opportunities for method development, both in terms of increasing model complexity and method fidelity. 2024-09-18T17:46:51Z 2024-09-18T17:46:51Z 2023-07-14 2024-09-18T17:33:46Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/156892 Vyshnavi Vennelakanti, Michael G. Taylor, Aditya Nandy, Chenru Duan, Heather J. Kulik; Assessing the performance of approximate density functional theory on 95 experimentally characterized Fe(II) spin crossover complexes. J. Chem. Phys. 14 July 2023; 159 (2): 024120. en 10.1063/5.0157187 The Journal of Chemical Physics Creative Commons Attribution https://creativecommons.org/licenses/by/4.0/ application/pdf AIP Publishing AIP Publishing
spellingShingle Vennelakanti, Vyshnavi
Taylor, Michael G
Nandy, Aditya
Duan, Chenru
Kulik, Heather J
Assessing the performance of approximate density functional theory on 95 experimentally characterized Fe(II) spin crossover complexes
title Assessing the performance of approximate density functional theory on 95 experimentally characterized Fe(II) spin crossover complexes
title_full Assessing the performance of approximate density functional theory on 95 experimentally characterized Fe(II) spin crossover complexes
title_fullStr Assessing the performance of approximate density functional theory on 95 experimentally characterized Fe(II) spin crossover complexes
title_full_unstemmed Assessing the performance of approximate density functional theory on 95 experimentally characterized Fe(II) spin crossover complexes
title_short Assessing the performance of approximate density functional theory on 95 experimentally characterized Fe(II) spin crossover complexes
title_sort assessing the performance of approximate density functional theory on 95 experimentally characterized fe ii spin crossover complexes
url https://hdl.handle.net/1721.1/156892
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