Chemical Shifts in Liquid Water Calculated by Molecular Dynamics Simulations and Shielding Polarizabilities

Nymand, Thomas M.; Åstrand, Per‐Olof; Mikkelsen, Kurt V.

doi:10.1021/jp9637338

Cited by 61 publications

(55 citation statements)

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“…6,7 Several theoretical models were proposed to describe the solvent effects on chemical shielding. [8][9][10][11][12][13][14] The main branches are the self-consistent reaction field methods (SCRF) 15,16 where the solute is placed inside a hollow cavity in a polarizable medium represented by its dielectric constant. In some cases, explicit solvent molecules, forming minimum energy clusters are considered in order to mimic the solvation shells of the solute.…”

Section: Introductionmentioning

confidence: 99%

Isotropic and anisotropic NMR chemical shifts in liquid water: a sequential QM/MM study

Fileti

Georg

Coutinho

et al. 2007

J. Braz. Chem. Soc.

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Apresentamos um estudo QM/MM seqüencial dos deslocamentos químicos gás-líquido da água. Cálculos de química quântica extensivos, usando a teoria do funcional da densidade foram realizados para estruturas do líquido de água, geradas através de simulações de Monte Carlo e Dinâmica Molecular. A dependência do deslocamento químico com os potenciais empíricos utilizados nas simulações, com o tamanho do aglomerado e com o funcional escolhido para os cálculos quânticos foi analisada. Os resultados corrigidos devido ao erro de superposição de base estão em boa concordância com os resultados experimentais, mostrando que um potencial empírico simples associado a um funcional apropriado é capaz de descrever os deslocamentos químicos. Todos os resultados apresentados são estatisticamente convergidos.We present a sequential QM/MM study of the gas-liquid chemical shifts of water. Extensive quantum chemical calculations using density functional theory have been performed for structures of liquid water generated by Monte Carlo and Molecular Dynamic simulations. The dependence of the chemical shifts on the empirical potential used in the simulations, on the cluster size and on the functional chosen for the quantum chemical calculations were analyzed. The results after correcting for basis set superposition errors are in good agreement with the experimental data, showing that a simple empirical potential associated to an appropriate functional is able to describe the chemical shifts. All results presented here are statistically converged. Keywords: sequential QM/MM, water, NMR, chemical shift, DFT IntroductionCalculations of the chemical shielding can reproduce with accuracy the chemical environment of the nuclei in a molecule. The advances in computational resources and the improvement in the theoretical methods provide important refinements to estimate the chemical shielding, such as inclusion of the electron correlation effects and the possibility of studying systems that are more complex than isolated molecules or small clusters. Presently the determination of the chemical shifts for nuclei in proteins, solids and liquids through current methodologies 1-5 are very convincing.An important category of systems whose electronic structure can be investigated through NMR calculations are solvated systems. A solvated molecule experiences the effect of the interaction with its vicinity, such as in hydrogen bonds. 6,7 Several theoretical models were proposed to describe the solvent effects on chemical shielding. [8][9][10][11][12][13][14] The main branches are the self-consistent reaction field methods (SCRF) 15,16 where the solute is placed inside a hollow cavity in a polarizable medium represented by its dielectric constant. In some cases, explicit solvent molecules, forming minimum energy clusters are considered in order to mimic the solvation shells of the solute. 10,17 It was shown that the former method does not work in determining the chemical shift and the latter, though it can serve as a rough approximation, does not serve as...

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Section: Introductionmentioning

confidence: 99%

Isotropic and anisotropic NMR chemical shifts in liquid water: a sequential QM/MM study

Fileti

Georg

Coutinho

et al. 2007

J. Braz. Chem. Soc.

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“…2. Recently the value of 324.0±1.5 ppm has been proposed as a reference for 17 O absolute shielding scale in the gas phase [14]. After some additional snapshots from molecular dynamics simulation and crystal data for ice were taken into account the so-called gas-to-liquid and gas-to-ice shifts have been determined [11].…”

Section: Figmentioning

confidence: 99%

“…The solvent (water) reaction field shifts this value up to 335.5 ppm. Hence, the changes in 17 O NMR signal positions of water structures are spread between the values of monomer in water solvent and ice. Note that, as in the case of 1 H NMR shifts, the 17 O magnetic shielding value of the "central" oxygen in tetrahedral pentamer lies again between those of bulk water and ice (Fig.…”

Section: Figmentioning

confidence: 99%

“…Because of fast molecular motion the NMR signal shifts in the liquids are determined by isotropic part of magnetic shielding tensors of corresponding nuclei. Most significant last period works on magnetic shielding properties of water are devoted either to pure quantum chemistry calculations or to some joint treatments applying molecular dynamics and chemical equilibrium theories [10][11][12][13][14][15][16][17][18][19]. Unfortunately most of them deal with water structures in vacuo, or presented data sets are not complete enough for the modelling of NMR spectra of mentioned systems.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic shielding properties of water in various molecular and molecular-ionic structures

Aidas¹

2006

Lithuanian J. Phys.

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H and17 O magnetic shielding tensors of water molecules in various water clusters, as well as in water-pyridine H-bond complexes and in molecular-ionic structure of Br − (H2O)6 have been calculated using density functional theory. The full geometry optimization was performed in the framework of Becke's three parameter hybrid method and the Lee-Yang-Parr correlation functional (B3LYP) combined with 6-311++G** basis set. Magnetic shielding tensors have been calculated using the hybrid functional of Perdew, Burke, and Ernzerhof (PBE1PBE) and the gauge-including atomic orbital (GIAO) approach was applied to ensure gauge invariance of the results. Solvent effects were taken into account by polarizable continuum model (PCM). The calculated NMR parameters are compared with the corresponding experimental data for aqueous system, which exhibit an unusual critical behaviour and phase transitions.

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“…The only exceptions are the investigations of fluoromethanes 6 and hydrogen selenide, 3 both of which used multiconfigurational SCF wave functions. We also mention the combined molecular dynamicsrdensity-functional theory study of liquid water by Malkin et al, 7 the combined molecular dynamicsrab initio 8 approach by Nymand, Astrand, and Mikkelsen of liquid water, and the study of solvent effects on the nuclear shieldings and spin᎐spin couplings of the acetylene molecule by Pecul and Sadlej. 9 In this article, we investigate the solvent effects on the parameters that determine an observable Ž NMR spectrum the magnetizability, the nuclear shielding constants, and the indirect spin᎐spin .…”

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confidence: 99%

Solvent effects on the NMR parameters of H2S and HCN

1999

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Chemical Shifts in Liquid Water Calculated by Molecular Dynamics Simulations and Shielding Polarizabilities

Cited by 61 publications

References 71 publications

Isotropic and anisotropic NMR chemical shifts in liquid water: a sequential QM/MM study

Isotropic and anisotropic NMR chemical shifts in liquid water: a sequential QM/MM study

Magnetic shielding properties of water in various molecular and molecular-ionic structures

Solvent effects on the NMR parameters of H2S and HCN

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