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Schenberg LA, Ducati LC, Autschbach J. Inquiring 199Hg NMR Parameters by Combining Ab Initio Molecular Dynamics and Relativistic NMR Calculations. Inorg Chem 2024; 63:2082-2089. [PMID: 38207278 DOI: 10.1021/acs.inorgchem.3c03878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Ab initio molecular dynamics (AIMD) sampling followed by relativistic density functional theory (DFT) 199Hg NMR calculations were performed for Hg organometallic complexes in water, dimethyl sulfoxide, and chloroform. The spin-orbit coupling, a relativistic effect, is a key factor for predicting δ(Hg) and 1J(Hg-C) accurately, in conjunction with a dynamic treatment of the systems. Good agreement between the theoretical and experimental results is reached by adopting implicit (based on a continuum model) and explicit (solvent molecules treated quantum mechanically) solvation models. Broader trends appearing in the experimental data available in the literature are reproduced by the calculations, and therefore, quantum chemistry is able to assist in the assignment and interpretation of 199Hg NMR data. Less pronounced trends, such as changes in the 199Hg chemical shift in different systems with the same atom types bound to Hg, are too weak to be predicted reliably by the current state-of-the-art theoretical methods based on AIMD sampling and relativistic DFT with hybrid functionals for NMR calculations.
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Affiliation(s)
- Leonardo Araujo Schenberg
- Department of Fundamental Chemistry, Institute of Chemistry University of Sao Paulo, Sao Paulo, Sao Paulo 05508-000, Brazil
| | - Lucas Colucci Ducati
- Department of Fundamental Chemistry, Institute of Chemistry University of Sao Paulo, Sao Paulo, Sao Paulo 05508-000, Brazil
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo State University of New York, Buffalo, New York 14260-3000, United States
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2
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Dorn RW, Carnahan SL, Cheng CY, Pan L, Hao Z, Rossini AJ. Structural characterization of tin in toothpaste by dynamic nuclear polarization enhanced 119Sn solid-state NMR spectroscopy. Nat Commun 2023; 14:7423. [PMID: 37973961 PMCID: PMC10654397 DOI: 10.1038/s41467-023-42816-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 10/20/2023] [Indexed: 11/19/2023] Open
Abstract
Stannous fluoride (SnF2) is an effective fluoride source and antimicrobial agent that is widely used in commercial toothpaste formulations. The antimicrobial activity of SnF2 is partly attributed to the presence of Sn(II) ions. However, it is challenging to directly determine the Sn speciation and oxidation state within commercially available toothpaste products due to the low weight loading of SnF2 (0.454 wt% SnF2, 0.34 wt% Sn) and the amorphous, semi-solid nature of the toothpaste. Here, we show that dynamic nuclear polarization (DNP) enables 119Sn solid-state NMR experiments that can probe the Sn speciation within commercially available toothpaste. Solid-state NMR experiments on SnF2 and SnF4 show that 19F isotropic chemical shift and 119Sn chemical shift anisotropy (CSA) are highly sensitive to the Sn oxidation state. DNP-enhanced 119Sn magic-angle turning (MAT) 2D NMR spectra of toothpastes resolve Sn(II) and Sn(IV) by their 119Sn chemical shift tensor parameters. Fits of DNP-enhanced 1D 1H → 119Sn solid-state NMR spectra allow the populations of Sn(II) and Sn(IV) within the toothpastes to be estimated. This analysis reveals that three of the four commercially available toothpastes contained at least 80% Sn(II), whereas one of the toothpaste contained a significantly higher amount of Sn(IV).
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Affiliation(s)
- Rick W Dorn
- US Department of Energy Ames National Laboratory, Ames, IA, 50011, USA
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
| | - Scott L Carnahan
- US Department of Energy Ames National Laboratory, Ames, IA, 50011, USA
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
| | | | - Long Pan
- Colgate-Palmolive Company, Piscataway, NJ, 08855, USA
| | - Zhigang Hao
- Colgate-Palmolive Company, Piscataway, NJ, 08855, USA.
| | - Aaron J Rossini
- US Department of Energy Ames National Laboratory, Ames, IA, 50011, USA.
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA.
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3
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Florez E, Zapata-Escobar AD, Ferraro F, Ibargüen Becerra C, Chamorro Y, Maldonado AF. Coordination of Mercury(II) in Water Promoted over Hydrolysis in Solvated Clusters [Hg(H 2O) 1-6] (aq)2+: Insights from Relativistic Effects and Free Energy Analysis. J Phys Chem A 2023; 127:8032-8049. [PMID: 37672217 DOI: 10.1021/acs.jpca.3c02927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
Understanding the nature of the interaction between mercury(II) ions, Hg2+, and water molecules is crucial to describe the stability and chemical behavior of structures formed during solvation, as well as the conditions that favor the Hg2+ coordination or inducing water hydrolysis. In our study, we explored exhaustively the potential energy surface of Hg2+ with up to six water molecules. We analyzed electronic and Gibbs free energies, binding, and nuclear magnetic resonance parameters. We used the zeroth-order regular approximation Hamiltonian, including scalar and spin-orbit relativistic corrections for free energy calculations and geometry optimizations to explore the interplay between electron correlation and relativistic effects. We analyzed intermolecular interactions with energy decomposition analysis, quantum theory of atoms in molecules, and natural bond orbital. Additionally, we used the four-component Dirac Hamiltonian to compute solvent effect on the magnetic shielding and J-coupling constants. Our results revealed that the water hydrolysis by Hg2+ requires a minimum of three water molecules. We found that the interaction between Hg2+ and water molecules is an orbital interaction due to relativistic effects and the most stable structures are opened-shape clusters, reducing the number of oxygen-mercury contacts and maximizing the formation of hydrogen bonds among water molecules. In these types of clusters, Hg2+ promotes the water hydrolysis over coordination with oxygen atoms. However, when we considered the change associated with the transfer of a cluster from the ideal gas to a solvated system, our solvation free energy analysis revealed that closed-shape clusters are more favorable, maximizing the number of oxygen-mercury contacts and reducing the formation of hydrogen bonds among water molecules. This finding suggests that, under room conditions, the coordination of Hg2+ is more favorable than hydrolysis. Our results have significant implications for understanding Hg2+ behavior in water, helping to develop targeted strategies for mercury remediation and management, and contributing to advancements in the broader field of environmental chemistry.
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Affiliation(s)
- Edison Florez
- Centre for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University, 0632 Auckland, New Zealand
| | - Andy D Zapata-Escobar
- Institute for Modeling and Innovative Technology (IMIT), CONICET-UNNE, W3404AAS Corrientes, Argentina
- Physics Department, Natural and Exact Science Faculty, Northeastern University, W3404AAS Corrientes, Argentina
| | - Franklin Ferraro
- Departamento de Ciencias Básicas, Universidad Católica Luis Amigó, 050034 Medellín, Colombia
| | - César Ibargüen Becerra
- Institute of Chemistry, University of Antioquia, 050010 Medellín, Colombia
- Facultad de Arquitectura e Ingeniería, Institución Universitaria Colegio Mayor de Antioquia (IUCMA), 050034 Medellín, Colombia
| | - Yuly Chamorro
- Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Alejandro F Maldonado
- Institute for Modeling and Innovative Technology (IMIT), CONICET-UNNE, W3404AAS Corrientes, Argentina
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4
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Saielli G. Computational NMR spectroscopy of 205 Tl. J Comput Chem 2023; 44:2016-2029. [PMID: 37367222 DOI: 10.1002/jcc.27176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 06/28/2023]
Abstract
We have investigated the NMR chemical shift of 205 Tl in several thallium compounds, ranging from small covalent Tl(I) and Tl(III) molecules to supramolecular complexes with large organic ligands and some thallium halides. NMR calculations were run at the ZORA relativistic level, with and without spin-orbit coupling using few selected GGA and hybrid functionals, namely BP86, PBE, B3LYP, and PBE0. We also tested solvent effects both at the optimization level and at the NMR calculation step. At the ZORA-SO-PBE0 (COSMO) level of theory we find a very good performance of the computational protocol that allows to discard or retain possible structures/conformations based on the agreement between the calculated chemical shift and the experimental value.
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Affiliation(s)
- Giacomo Saielli
- CNR Institute on Membrane Technology, Unit of Padova, Padova, Italy
- Department of Chemical Sciences, University of Padova, Padova, Italy
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5
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Mirzaeva I. Large relativistic effects in 119Sn NMR parameters: A case study of complex anions [Cp*M(SnCl3)nCl3−n]−, where M = Rh, Ir; n = 1, 2, 3. COMPUT THEOR CHEM 2021. [DOI: 10.1016/j.comptc.2021.113432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Copéret C, Liao WC, Gordon CP, Ong TC. Active Sites in Supported Single-Site Catalysts: An NMR Perspective. J Am Chem Soc 2017; 139:10588-10596. [DOI: 10.1021/jacs.6b12981] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Christophe Copéret
- Department of Chemistry and
Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, CH-8093 Zürich, Switzerland
| | - Wei-Chih Liao
- Department of Chemistry and
Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, CH-8093 Zürich, Switzerland
| | - Christopher P. Gordon
- Department of Chemistry and
Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, CH-8093 Zürich, Switzerland
| | - Ta-Chung Ong
- Department of Chemistry and
Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, CH-8093 Zürich, Switzerland
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Alkan F, Holmes ST, Iuliucci RJ, Mueller KT, Dybowski C. Spin-orbit effects on the (119)Sn magnetic-shielding tensor in solids: a ZORA/DFT investigation. Phys Chem Chem Phys 2016; 18:18914-22. [PMID: 27354312 DOI: 10.1039/c6cp03807g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Periodic-boundary and cluster calculations of the magnetic-shielding tensors of (119)Sn sites in various co-ordination and stereochemical environments are reported. The results indicate a significant difference between the predicted NMR chemical shifts for tin(ii) sites that exhibit stereochemically-active lone pairs and tin(iv) sites that do not have stereochemically-active lone pairs. The predicted magnetic shieldings determined either with the cluster model treated with the ZORA/Scalar Hamiltonian or with the GIPAW formalism are dependent on the oxidation state and the co-ordination geometry of the tin atom. The inclusion of relativistic effects at the spin-orbit level removes systematic differences in computed magnetic-shielding parameters between tin sites of differing stereochemistries, and brings computed NMR shielding parameters into significant agreement with experimentally-determined chemical-shift principal values. Slight improvement in agreement with experiment is noted in calculations using hybrid exchange-correlation functionals.
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Affiliation(s)
- Fahri Alkan
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
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8
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Flórez E, Maldonado AF, Aucar GA, David J, Restrepo A. Microsolvation of methylmercury: structures, energies, bonding and NMR constants (199Hg,13C and17O). Phys Chem Chem Phys 2016; 18:1537-50. [DOI: 10.1039/c5cp04826e] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hartree–Fock (HF) and second order perturbation theory (MP2) calculations within the scalar and full relativistic frames were carried out in order to determine the equilibrium geometries and interaction energies between cationic methylmercury (CH3Hg+) and up to three water molecules.
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Affiliation(s)
- Edison Flórez
- Instituto de Química
- Universidad de Antioquia UdeA
- Medellín
- Colombia
| | - Alejandro F. Maldonado
- Physics Department
- Natural and Exact Science Faculty
- Northeastern University of Argentina and Institute of Modelling and Innovation on Technology
- IMIT
- Corrientes
| | - Gustavo A. Aucar
- Physics Department
- Natural and Exact Science Faculty
- Northeastern University of Argentina and Institute of Modelling and Innovation on Technology
- IMIT
- Corrientes
| | - Jorge David
- Departamento de Ciencias Físicas
- Universidad EAFIT
- Medellín
- Colombia
| | - Albeiro Restrepo
- Instituto de Química
- Universidad de Antioquia UdeA
- Medellín
- Colombia
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9
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Alkan F, Dybowski C. Calculation of chemical-shift tensors of heavy nuclei: a DFT/ZORA investigation of 199Hg chemical-shift tensors in solids, and the effects of cluster size and electronic-state approximations. Phys Chem Chem Phys 2014; 16:14298-308. [DOI: 10.1039/c4cp01682c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A ZORA/DFT investigation of the NMR chemical shielding of a suite of 199Hg-containing solid materials shows the importance of calculations with the molecular-cluster method.
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Affiliation(s)
- Fahri Alkan
- Department of Chemistry and Biochemistry
- University of Delaware
- Newark, USA
| | - C. Dybowski
- Department of Chemistry and Biochemistry
- University of Delaware
- Newark, USA
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10
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Autschbach J. The role of the exchange-correlation response kernel and scaling corrections in relativistic density functional nuclear magnetic shielding calculations with the zeroth-order regular approximation. Mol Phys 2013. [DOI: 10.1080/00268976.2013.796415] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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11
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Autschbach J. Relativistic Effects on NMR Parameters. SCIENCE AND TECHNOLOGY OF ATOMIC, MOLECULAR, CONDENSED MATTER & BIOLOGICAL SYSTEMS 2013. [DOI: 10.1016/b978-0-444-59411-2.00004-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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12
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Arcisauskaite V, Melo JI, Hemmingsen L, Sauer SPA. Nuclear magnetic resonance shielding constants and chemical shifts in linear 199Hg compounds: A comparison of three relativistic computational methods. J Chem Phys 2011; 135:044306. [DOI: 10.1063/1.3608153] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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14
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Zheng S, Autschbach J. Modeling of heavy-atom-ligand NMR spin-spin coupling in solution: molecular dynamics study and natural bond orbital analysis of Hg-C coupling constants. Chemistry 2010; 17:161-73. [PMID: 21207613 DOI: 10.1002/chem.201001343] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Indexed: 11/11/2022]
Abstract
Ab initio molecular dynamics (MD) and relativistic density functional NMR methods were applied to calculate the one-bond Hg-C NMR indirect nuclear spin-spin coupling constants (J) of [Hg(CN)(2) ] and [CH(3) HgCl] in solution. The MD averages were obtained as J((199) Hg-(13) C)=3200 and 1575 Hz, respectively. The experimental Hg-C spin-spin coupling constants of [Hg(CN)(2) ] in methanol and [CH(3) HgCl] in DMSO are 3143 and 1674 Hz, respectively. To deal with solvent effects in the calculations, finite "droplet" models of the two systems were set up. Solvent effects in both systems lead to a strong increase of the Hg-C coupling constant. From a relativistic natural localized molecular orbital (NLMO) analysis, it was found that the degree of delocalization of the Hg 5d(σ) nonbonding orbital and of the HgC bonding orbital between the two coupled atoms, the nature of the trans Hg-C/Cl bonding orbital, and the s character of these orbitals, exhibit trends upon solvation of the complexes that, when combined, lead to the strong increase of J(Hg-C).
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Affiliation(s)
- Shaohui Zheng
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA
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15
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Relativistic Effects on Magnetic Resonance Parameters and Other Properties of Inorganic Molecules and Metal Complexes. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/978-1-4020-9975-5_12] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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16
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Boshaala AMA, Simpson SJ, Autschbach J, Zheng S. Synthesis and Characterization of the Trihalophosphine Compounds of Ruthenium [RuX2(η6-cymene)(PY3)] (X = Cl, Br, Y = F, Cl, Br) and the Related PF2(NMe2) and P(NMe2)3 Compounds; Multinuclear NMR Spectroscopy and the X-ray Single Crystal Structures of [RuBr2(η6-cymene)(PF3)], [RuBr2(η6-cymene)(PF2{NMe2})], and [RuI2(η6-cymene)(P{NMe2}3)]. Inorg Chem 2008; 47:9279-92. [DOI: 10.1021/ic800611h] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Ahmed M. A. Boshaala
- Institute of Materials Research, University of Salford, Salford M5 4WT, U.K., School of Biosciences, University of Exeter, 216B Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, U.K., and Department of Chemistry, 312 Natural Sciences Complex, State University of New York at Buffalo, Buffalo, New York 14260-3000
| | - Stephen J. Simpson
- Institute of Materials Research, University of Salford, Salford M5 4WT, U.K., School of Biosciences, University of Exeter, 216B Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, U.K., and Department of Chemistry, 312 Natural Sciences Complex, State University of New York at Buffalo, Buffalo, New York 14260-3000
| | - Jochen Autschbach
- Institute of Materials Research, University of Salford, Salford M5 4WT, U.K., School of Biosciences, University of Exeter, 216B Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, U.K., and Department of Chemistry, 312 Natural Sciences Complex, State University of New York at Buffalo, Buffalo, New York 14260-3000
| | - Shaohui Zheng
- Institute of Materials Research, University of Salford, Salford M5 4WT, U.K., School of Biosciences, University of Exeter, 216B Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, U.K., and Department of Chemistry, 312 Natural Sciences Complex, State University of New York at Buffalo, Buffalo, New York 14260-3000
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17
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Casabianca LB, de Dios AC. Ab initiocalculations of NMR chemical shifts. J Chem Phys 2008; 128:052201. [DOI: 10.1063/1.2816784] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
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18
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Briand GG, Smith AD, Schatte G, Rossini AJ, Schurko RW. Probing lead(II) bonding environments in 4-substituted pyridine adducts of (2,6-Me2C6H3S)2Pb: an X-ray structural and solid-state 207Pb NMR study. Inorg Chem 2007; 46:8625-37. [PMID: 17867676 DOI: 10.1021/ic700738w] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effect of subtle changes in the sigma-electron donor ability of 4-substituted pyridine ligands on the lead(II) coordination environment of (2,6-Me(2)C(6)H(3)S)(2)Pb (1) adducts has been examined. The reaction of 1 with a series of 4-substituted pyridines in toluene or dichloromethane results in the formation of 1:1 complexes [(2,6-Me(2)C(6)H(3)S)(2)Pb(pyCOH)](2) (3), [(2,6-Me(2)C(6)H(3)S)(2)Pb(pyOMe)](2) (4), and (2,6-Me(2)C(6)H(3)S)(2)Pb(pyNMe(2)) (5) (pyCOH = 4-pyridinecarboxaldehyde; pyOMe = 4-methoxypyridine; pyNMe2 = 4-dimethylaminopyridine), all of which have been structurally characterized by X-ray crystallography. The structures of 3 and 4 are dimeric and have psi-trigonal bipyramidal S(3)N bonding environments, with the 4-substituted pyridine nitrogen and bridging sulfur atoms in axial positions and two thiolate sulfur atoms in equatorial sites. Conversely, compound 5 is monomeric and exhibits a psi-trigonal pyramidal S(2)N bonding environment at lead(II). The observed structures may be rationalized in terms of a simple valence bond model and the sigma-electron donor ability of the 4-pyridine ligands as derived from the analysis of proton affinity values. Solid-state (207)Pb NMR experiments are applied in combination with density functional theory (DFT) calculations to provide further insight into the nature of bonding in 4, 5, and (2,6-Me(2)C(6)H(3)S)(2)Pb(py)(2) (2). The lead chemical shielding (CS) tensor parameters of 2, 4, and 5 reveal some of the largest chemical shielding anisotropies (CSA) observed in lead coordination complexes to date. DFT calculations using the Amsterdam Density Functional (ADF) program, which take into account relativistic effects using the zeroth-order regular approximation (ZORA), yield lead CS tensor components and orientations. Paramagnetic contributions to the lead CS tensor from individual pairs of occupied and virtual molecular orbitals (MOs) are examined to gain insight into the origin of the large CSA. The CS tensor is primarily influenced by mixing of the occupied MOs localized on the sulfur and lead atoms with virtual MOs largely comprised of lead 6p orbitals.
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Affiliation(s)
- Glen G Briand
- Department of Chemistry, Mount Allison University, Sackville, New Brunswick, Canada E4L 1G8.
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19
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Autschbach J, Sterzel M. Molecular Dynamics Computational Study of the199Hg−199Hg NMR Spin−Spin Coupling Constants of [Hg−Hg−Hg]2+in SO2Solution. J Am Chem Soc 2007; 129:11093-9. [PMID: 17713908 DOI: 10.1021/ja073166+] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The isotropic one-bond and two-bond 199Hg-199Hg nuclear magnetic spin-spin coupling constants (J-couplings) of [Hg-Hg-Hg]2+ were calculated using density functional theory, the zeroth-order regular approximation (ZORA) to treat relativistic effects, and Born-Oppenheimer molecular dynamics (BOMD) including SO2 molecules explicitly for the description of solvent effects. The final BOMD average of 150 kHz for 1J (199Hg-199Hg) agrees well with the experimental spin-spin coupling of 140 kHz measured in liquid SO2, while computations not considering explicit solvation at the quantum-mechanical level yielded one-bond coupling constants between 230 and 260 kHz. The two-bond coupling is similarly strongly affected by solvent effects. An analysis of the BOMD data shows that the effect is mainly due to close contacts between the terminal Hg atoms of [Hg-Hg-Hg]2+ and the solvent's oxygen atoms. The results highlight the importance of solvent effects for the NMR parameter of heavy metals and demonstrate the usefulness of treating such solvent effects with the help of molecular dynamics-based averaging.
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Affiliation(s)
- Jochen Autschbach
- Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260-3000, USA.
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20
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Autschbach J, Kantola AM, Jokisaari J. NMR Measurements and Density Functional Calculations of the 199Hg−13C Spin−Spin Coupling Tensor in Methylmercury Halides. J Phys Chem A 2007; 111:5343-8. [PMID: 17521175 DOI: 10.1021/jp0713817] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The isotropic average, JisoHgC, and the anisotropy, DeltaJHgC, of the 199Hg-13C spin-spin coupling tensor in methylmercury halides, CH3HgX (X=Cl, Br, I), were determined for the first time by utilizing the NMR spectra of these molecules dissolved in liquid crystals. Furthermore, density functional calculations were performed using the zeroth-order regular approximation, including also dimethylmercury. The temperature-dependence of the JisoHgC couplings in the isotropic phase was studied in each case in order to extrapolate their values into the liquid crystal state. Good agreement is found between the experimental and the calculated DeltaJHgC values as long as solvent effects are considered in the computations. Most of the magnitude of DeltaJ can be attributed to the spin mechanism of J-coupling, with additional sizable spin-orbital cross terms due to electronic spin-orbit coupling.
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Affiliation(s)
- Jochen Autschbach
- Department of Chemistry, State University of New York at Buffalo, 312 Natural Sciences Complex, Buffalo, New York 14260-3000, USA.
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21
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Bagno A, Bonchio M, Autschbach J. Computational Modeling of Polyoxotungstates by Relativistic DFT Calculations of183W NMR Chemical Shifts. Chemistry 2006; 12:8460-71. [PMID: 16927351 DOI: 10.1002/chem.200600488] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The (183)W nuclear shielding in a variety of tungsten polyoxometalates (POM) (Lindqvist, Anderson, decatungstates, Keggin) of different shapes and charges has been modeled by DFT calculations that take into account relativistic effects, by means of the zero-order regular approximation (ZORA), and solvent effects, by the conductor-like screening model (COSMO) continuum method. The charge/surface area ratio (q/A) is proposed as an indicator of the charge density to which the solvation energies of all POMs are correlated in a satisfactory way. Among the various theoretical levels tested (ZORA scalar or spin-orbit, frozen-core or all-electron basis set, geometry optimization in the gas phase or in the continuum solvent, etc.), the best results are obtained when both geometry optimization in solvent and spin-orbit shielding are included (mean absolute error of delta=35 ppm). The quality of the computed chemical shifts depends systematically on the charge density as expressed by q/A; thus, POMs with low q/A ratios display the best agreement with experimental data. The performance of the method is such that computed values can aid the assignment of the (183)W NMR spectra of polyoxotungstates, as shown by the case of alpha-[PW(11)TiO(40)](5-), whose six signals are ranked computationally so as to almost reproduce the experimental ordering even though the signals are spaced by as little as 5 ppm.
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Affiliation(s)
- Alessandro Bagno
- Dipartimento di Scienze Chimiche, Università di Padova via Marzolo 1, 35131 Padova, Italy.
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Bowmaker GA, Assadollahzadeh B, Brodie AM, Ainscough EW, Freeman GH, Jameson GB. Structural and spectroscopic studies on mercury(II) tribenzylphosphine complexes. Dalton Trans 2005:1602-12. [PMID: 15852109 DOI: 10.1039/b419253b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The tribenzylphosphine (PBz3) complexes of mercury(II), [Hg(PBz3)2](BF4)2, [Hg(PBz3)2(NO3)2] and [HgX(NO3)(PBz3)](X = Cl, Br, I and SCN), have been synthesised and their structures determined by single-crystal X-ray crystallography. [Hg(PBz3)2](BF4)2 contains [Hg(PBz3)2]2+ cations with linear P-Hg-P coordination, the first example of a truly two-coordinate [Hg(PR3)2]2+ complex. The mercury coordination in [Hg(PBz3)2(NO3)2] can be described as distorted tetrahedral, with a significant deviation of the P-Hg-P angle from linearity as a result of coordination of the nitrate groups. Nitrate coordination is also observed in [HgX(NO3)(PBz3)](X = Cl, Br, I), resulting in significantly non-linear P-Hg-X coordination. The thiocyanate complex is a centrosymmetric thiocyanate-bridged dimer with distorted trigonal-pyramidal mercury coordination to the P atom of PBz3, to the S and N atoms of two bridging thiocyanate groups, and to the O atom of one nitrate group. For all the nitrato complexes, secondary mercury-nitrate interactions (Hg-O 2.7-3.1 A) effectively raise the coordination number of the Hg(II) centres to six. High-resolution 31P solid-state NMR spectra of the six tribenzylphosphine mercury(II)-complexes, obtained by combining magic-angle spinning, proton dipolar decoupling and proton-phosphorus cross-polarization (CP-MAS), have been recorded. The spectra of [Hg(PBz3)2](BF4)2 and [HgX(NO3)(PBz3)](X = Cl, Br, I and SCN) exhibit a single line, due to species that contain non-magnetic isotopes of mercury, and satellite lines, due to 1J(31P-199Hg) coupling. The asymmetric unit of [Hg(PBz3)2(NO3)2] contains two molecules with four phosphorus environments, resulting in two AB spectra with 2J(31P-31P) coupling, due to species that contain non-magnetic isotopes of mercury, and satellite lines consisting of two ABX spectra, due to 1J(31P-199Hg) coupling. These spectra have been analysed to yield all of the chemical shifts and coupling constants involved. A remarkable increase in 1J(31P-199Hg) is observed from [Hg(PBz3)2](BF4)2 to [Hg(PBz3)2(NO3)2] as a consequence of the incorporation of the nitrate group into the Hg coordination sphere in the latter case. Several of the spectra also exhibit broader satellites due to the presence of scalar spin-spin coupling between 31P and the quadrupolar 201Hg nucleus. Slow-spinning methods have been used to analyze the spinning-sideband intensities of the NMR spectra, in order to obtain the 31P shielding anisotropy and asymmetry parameters Deltasigma and eta. The 199Hg and 31P NMR shielding tensors of PMe3 models of the above six compounds have been calculated using relativistic density functional theory. The 31P results are in good agreement with experiment and assist in the assignment of some of the signals.
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Affiliation(s)
- Graham A Bowmaker
- Department of Chemistry, University of Auckland, Private Bag 92 019, Auckland, New Zealand.
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Siegel R, Nakashima TT, Wasylishen RE. Application of Multiple-Pulse Experiments to Characterize Broad NMR Chemical-Shift Powder Patterns from Spin-1/2 Nuclei in the Solid State. J Phys Chem B 2004. [DOI: 10.1021/jp031048c] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Renée Siegel
- Department of Chemistry, Gunning/Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Thomas T. Nakashima
- Department of Chemistry, Gunning/Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Roderick E. Wasylishen
- Department of Chemistry, Gunning/Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
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Kaupp M. Relativistic Effects on NMR Chemical Shifts. THEORETICAL AND COMPUTATIONAL CHEMISTRY 2004. [DOI: 10.1016/s1380-7323(04)80036-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Autschbach J, Zurek E. Relativistic Density-Functional Computations of the Chemical Shift of 129Xe in Xe@C60. J Phys Chem A 2003. [DOI: 10.1021/jp0346559] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jochen Autschbach
- Lehrstuhl für Theoretische Chemie, Universität Erlangen, Egerlandstraβe 3, D-91058 Erlangen, Germany
| | - Eva Zurek
- Lehrstuhl für Theoretische Chemie, Universität Erlangen, Egerlandstraβe 3, D-91058 Erlangen, Germany
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Autschbach J, Igna CD, Ziegler T. A theoretical study of the large Hg-Hg spin-spin coupling constants in Hg(2)(2+), Hg(3)(2+), and Hg(2)(2+)-crown ether complexes. J Am Chem Soc 2003; 125:4937-42. [PMID: 12696913 DOI: 10.1021/ja028721g] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nuclear spin-spin coupling constants (1)J(Hg-Hg) in the systems Hg(2)(2+) and Hg(3)(2+) represent the largest coupling constants so far observed in NMR experiments. We have performed a computational study on these ions, on Hg(2)(2+) complexes with 18-crown-6 and 15-crown-5, and on Hg(3)(2+) with solvent molecules and counterions. The results obtained with our recently developed program for the density functional computation of heavy nucleus spin-spin coupling constants are in good agreement with experiments. The data reveal that the bare ions Hg(2)(2+) and Hg(3)(2+) would afford much larger coupling constants than those experimentally observed, with an upper limit of approximately 0.9 MHz for Hg(2)(2+). This limit is much larger than that previously estimated by Hückel theory. It is demonstrated that in solution or due to complexation the experimentally determined values are much smaller than the free ion's coupling constants. With the help of intuitive MO arguments, it is illustrated how the environment strongly reduces the coupling constants in Hg(2)(2+) and Hg(3)(2+). The two-bond coupling constant (2)J(Hg-Hg) in Hg(3)(2+) is also examined.
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Affiliation(s)
- Jochen Autschbach
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N-1N4
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Jokisaari J, Autschbach J. 13C–77Se and77Se–77Se spin–spin coupling tensors in carbon diselenide: NMR experiments and ZORA DFT calculations. Phys Chem Chem Phys 2003. [DOI: 10.1039/b305442j] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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