Nuclear magnetic resonance shielding constants and chemical shifts in linear 199Hg compounds: A comparison of three relativistic computational methods
We investigate the importance of relativistic effects on NMR shielding constants and chemical shifts of linear HgL2 (L = Cl, Br, I, CH 3) compounds using three different relativistic methods: the fully relativistic four-component approach and the two-component approximations, linear response elimina...
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2011
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00219606_v135_n4_p_Arcisauskaite http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00219606_v135_n4_p_Arcisauskaite_oai |
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I28-R145-paper_00219606_v135_n4_p_Arcisauskaite_oai2020-10-19 Arcisauskaite, V. Melo, J.I. Hemmingsen, L. Sauer, S.P.A. 2011 We investigate the importance of relativistic effects on NMR shielding constants and chemical shifts of linear HgL2 (L = Cl, Br, I, CH 3) compounds using three different relativistic methods: the fully relativistic four-component approach and the two-component approximations, linear response elimination of small component (LR-ESC) and zeroth-order regular approximation (ZORA). LR-ESC reproduces successfully the four-component results for the C shielding constant in Hg(CH3)2 within 6 ppm, but fails to reproduce the Hg shielding constants and chemical shifts. The latter is mainly due to an underestimation of the change in spin-orbit contribution. Even though ZORA underestimates the absolute Hg NMR shielding constants by ∼2100 ppm, the differences between Hg chemical shift values obtained using ZORA and the four-component approach without spin-density contribution to the exchange-correlation (XC) kernel are less than 60 ppm for all compounds using three different functionals, BP86, B3LYP, and PBE0. However, larger deviations (up to 366 ppm) occur for Hg chemical shifts in HgBr 2 and HgI2 when ZORA results are compared with four-component calculations with non-collinear spin-density contribution to the XC kernel. For the ZORA calculations it is necessary to use large basis sets (QZ4P) and the TZ2P basis set may give errors of ∼500 ppm for the Hg chemical shifts, despite deceivingly good agreement with experimental data. A Gaussian nucleus model for the Coulomb potential reduces the Hg shielding constants by ∼100-500 ppm and the Hg chemical shifts by 1-143 ppm compared to the point nucleus model depending on the atomic number Z of the coordinating atom and the level of theory. The effect on the shielding constants of the lighter nuclei (C, Cl, Br, I) is, however, negligible. © 2011 American Institute of Physics. Fil:Melo, J.I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. application/pdf http://hdl.handle.net/20.500.12110/paper_00219606_v135_n4_p_Arcisauskaite info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar J Chem Phys 2011;135(4) Atomic numbers Basis sets Coulomb potential Exchange-correlations Experimental data Functionals Gaussians Linear response NMR shielding Nuclear magnetic resonance shielding Point nuclei Relativistic effects Shielding constants Small components Spin densities Spin orbits Two-component Zeroth-order regular approximations Atoms Bromine Chemical compounds Chemical shift Chlorine Electric fields Iodine Mercury (metal) Resonance Magnetic shielding mercury mercury derivative article chemistry comparative study computer analysis methodology nuclear magnetic resonance spectroscopy quantum theory Computing Methodologies Magnetic Resonance Spectroscopy Mercury Compounds Mercury Isotopes Quantum Theory Nuclear magnetic resonance shielding constants and chemical shifts in linear 199Hg compounds: A comparison of three relativistic computational methods info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00219606_v135_n4_p_Arcisauskaite_oai |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-145 |
| collection |
Repositorio Digital de la Universidad de Buenos Aires (UBA) |
| topic |
Atomic numbers Basis sets Coulomb potential Exchange-correlations Experimental data Functionals Gaussians Linear response NMR shielding Nuclear magnetic resonance shielding Point nuclei Relativistic effects Shielding constants Small components Spin densities Spin orbits Two-component Zeroth-order regular approximations Atoms Bromine Chemical compounds Chemical shift Chlorine Electric fields Iodine Mercury (metal) Resonance Magnetic shielding mercury mercury derivative article chemistry comparative study computer analysis methodology nuclear magnetic resonance spectroscopy quantum theory Computing Methodologies Magnetic Resonance Spectroscopy Mercury Compounds Mercury Isotopes Quantum Theory |
| spellingShingle |
Atomic numbers Basis sets Coulomb potential Exchange-correlations Experimental data Functionals Gaussians Linear response NMR shielding Nuclear magnetic resonance shielding Point nuclei Relativistic effects Shielding constants Small components Spin densities Spin orbits Two-component Zeroth-order regular approximations Atoms Bromine Chemical compounds Chemical shift Chlorine Electric fields Iodine Mercury (metal) Resonance Magnetic shielding mercury mercury derivative article chemistry comparative study computer analysis methodology nuclear magnetic resonance spectroscopy quantum theory Computing Methodologies Magnetic Resonance Spectroscopy Mercury Compounds Mercury Isotopes Quantum Theory Arcisauskaite, V. Melo, J.I. Hemmingsen, L. Sauer, S.P.A. Nuclear magnetic resonance shielding constants and chemical shifts in linear 199Hg compounds: A comparison of three relativistic computational methods |
| topic_facet |
Atomic numbers Basis sets Coulomb potential Exchange-correlations Experimental data Functionals Gaussians Linear response NMR shielding Nuclear magnetic resonance shielding Point nuclei Relativistic effects Shielding constants Small components Spin densities Spin orbits Two-component Zeroth-order regular approximations Atoms Bromine Chemical compounds Chemical shift Chlorine Electric fields Iodine Mercury (metal) Resonance Magnetic shielding mercury mercury derivative article chemistry comparative study computer analysis methodology nuclear magnetic resonance spectroscopy quantum theory Computing Methodologies Magnetic Resonance Spectroscopy Mercury Compounds Mercury Isotopes Quantum Theory |
| description |
We investigate the importance of relativistic effects on NMR shielding constants and chemical shifts of linear HgL2 (L = Cl, Br, I, CH 3) compounds using three different relativistic methods: the fully relativistic four-component approach and the two-component approximations, linear response elimination of small component (LR-ESC) and zeroth-order regular approximation (ZORA). LR-ESC reproduces successfully the four-component results for the C shielding constant in Hg(CH3)2 within 6 ppm, but fails to reproduce the Hg shielding constants and chemical shifts. The latter is mainly due to an underestimation of the change in spin-orbit contribution. Even though ZORA underestimates the absolute Hg NMR shielding constants by ∼2100 ppm, the differences between Hg chemical shift values obtained using ZORA and the four-component approach without spin-density contribution to the exchange-correlation (XC) kernel are less than 60 ppm for all compounds using three different functionals, BP86, B3LYP, and PBE0. However, larger deviations (up to 366 ppm) occur for Hg chemical shifts in HgBr 2 and HgI2 when ZORA results are compared with four-component calculations with non-collinear spin-density contribution to the XC kernel. For the ZORA calculations it is necessary to use large basis sets (QZ4P) and the TZ2P basis set may give errors of ∼500 ppm for the Hg chemical shifts, despite deceivingly good agreement with experimental data. A Gaussian nucleus model for the Coulomb potential reduces the Hg shielding constants by ∼100-500 ppm and the Hg chemical shifts by 1-143 ppm compared to the point nucleus model depending on the atomic number Z of the coordinating atom and the level of theory. The effect on the shielding constants of the lighter nuclei (C, Cl, Br, I) is, however, negligible. © 2011 American Institute of Physics. |
| format |
Artículo Artículo publishedVersion |
| author |
Arcisauskaite, V. Melo, J.I. Hemmingsen, L. Sauer, S.P.A. |
| author_facet |
Arcisauskaite, V. Melo, J.I. Hemmingsen, L. Sauer, S.P.A. |
| author_sort |
Arcisauskaite, V. |
| title |
Nuclear magnetic resonance shielding constants and chemical shifts in linear 199Hg compounds: A comparison of three relativistic computational methods |
| title_short |
Nuclear magnetic resonance shielding constants and chemical shifts in linear 199Hg compounds: A comparison of three relativistic computational methods |
| title_full |
Nuclear magnetic resonance shielding constants and chemical shifts in linear 199Hg compounds: A comparison of three relativistic computational methods |
| title_fullStr |
Nuclear magnetic resonance shielding constants and chemical shifts in linear 199Hg compounds: A comparison of three relativistic computational methods |
| title_full_unstemmed |
Nuclear magnetic resonance shielding constants and chemical shifts in linear 199Hg compounds: A comparison of three relativistic computational methods |
| title_sort |
nuclear magnetic resonance shielding constants and chemical shifts in linear 199hg compounds: a comparison of three relativistic computational methods |
| publishDate |
2011 |
| url |
http://hdl.handle.net/20.500.12110/paper_00219606_v135_n4_p_Arcisauskaite http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00219606_v135_n4_p_Arcisauskaite_oai |
| work_keys_str_mv |
AT arcisauskaitev nuclearmagneticresonanceshieldingconstantsandchemicalshiftsinlinear199hgcompoundsacomparisonofthreerelativisticcomputationalmethods AT meloji nuclearmagneticresonanceshieldingconstantsandchemicalshiftsinlinear199hgcompoundsacomparisonofthreerelativisticcomputationalmethods AT hemmingsenl nuclearmagneticresonanceshieldingconstantsandchemicalshiftsinlinear199hgcompoundsacomparisonofthreerelativisticcomputationalmethods AT sauerspa nuclearmagneticresonanceshieldingconstantsandchemicalshiftsinlinear199hgcompoundsacomparisonofthreerelativisticcomputationalmethods |
| _version_ |
1766026572138020864 |