Three-body Effects in Calcium(II)-ammonia Solutions: Molecular Dynamics Simulations

Sidhisoradej, Wiwat; Hannongbua, Supot; Ruffolo, D.

doi:10.1515/zna-1998-0518

Cited by 11 publications

(11 citation statements)

References 20 publications

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“…48 The situation is not different for Mg 2+ , where only an early proton magnetic resonance study is reported in which CN = 6 was found. 49 The ammonia solvation of Ca 2+ has been studied theoretically; [43][44][45][46][47]50 however, basic information about the structure of the dominant solvation motif is still unclear. Sidhisoradej et al performed molecular dynamics (MD) simulations of infinitely dilute Ca 2+ −ammonia solutions including two-and three-body effects.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Sidhisoradej et al performed molecular dynamics (MD) simulations of infinitely dilute Ca 2+ −ammonia solutions including two-and three-body effects. 47 They found that the inclusion of three-body corrections produces CN = 8 with an average Ca−N distance of 2.86 Å, while taking into account that only two-body interactions produce CN = 9 at a distance of 2.53 Å. Floris et al developed an effective ab initio pair potential 45 and used it to search for local minimum structures of [Ca(NH 3 ) n ] 2+ with n ≤ 10; they employed it later to conduct molecular dynamics simulations of aqueous solutions containing ammonia. 50 Kerdcharoen et al performed quantum mechanics/molecular mechanics (QM/MM) MD simulations (under the ONIOM framework) 43 and found that Ca 2+ is sixcoordinate in a near-octahedral fashion with a mean Ca−N distance of 2.53 Å.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Most of the previous solvation studies of Mg 2+ and Ca 2+ have focused on water and methanol as solvents, ,− while ammonia solvation is less studied. ,,− In particular, studies under ammonia microsolvation conditions are quite scarce…”

Section: Introductionmentioning

confidence: 99%

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Mg(II) and Ca(II) Microsolvation by Ammonia: Born–Oppenheimer Molecular Dynamics Studies

León-Pimentel

Saint-Martı́n²,

Ramı́rez-Solı́s

2021

J. Phys. Chem. A

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We report the structural and energetic features of the Mg2+ and Ca2+ cations in ammonia microsolvation environments. Born–Oppenhemier molecular dynamics studies are carried out for [Mg(NH3) n ]2+ and [Ca(NH3) n ]2+ clusters with n = 2, 3, 4, 6, 8, 20, and 27 at 300 K based on hybrid density functional theory calculations. We determine binding energies per ammonia molecule and the metal cation solvation patterns as a function of the number of molecules. The general trend for Mg2+ is that the Mg–N distances increase as a function of n until the first solvation shell is populated by six ammonia molecules, and then the distances slightly decrease while CN = 6 does not change. For Ca2+, the first solvation shell at room temperature is populated by eight ammonia molecules for clusters with more than one solvation shell, leading to a different structure from that of [Ca(NH3)6]2+ hexamine. The evaporation of NH3 molecules was found at 300 K only for Mg2+ clusters with n ≥ 10; this was not the case for Ca2+ clusters. Vibrational spectra are obtained for all of the clusters, and the evolution of the main features is discussed. EXAFS spectra are also presented for the [Mg(NH3)27(NH3)27]2+ and [Ca(NH3)27]2+ clusters, which yield valuable data to be compared with experimental data in the liquid phase, as previously done for the aqueous solvation of these dications.

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Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Mg(II) and Ca(II) Microsolvation by Ammonia: Born–Oppenheimer Molecular Dynamics Studies

León-Pimentel

Saint-Martı́n²,

Ramı́rez-Solı́s

2021

J. Phys. Chem. A

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“…Most of the statistical simulations performed so far and dealing with the solvation phenomenon of this cation are specifically devoted to the study of the hydration 4 -18 of calcium ion, and, marginally, solvation properties including other solvents have been considered at a quantum chemical level. [19][20][21][22][23] To our best knowledge, only the work done by Sidhisoradej et al 24 studies the solvation of Ca 2ϩ in liquid ammonia by means of molecular dynamics ͑MD͒ simulations using a potential function which explicitly considers threebody effects in the ion-solvent potential. However, studies including more than one solvent have not been considered so far, despite being the most common situation in the biological media.…”

Section: Introductionmentioning

confidence: 99%

Preferential solvation of Ca2+ in aqueous solutions containing ammonia: A molecular dynamics study

Floris

Martı́nez

Tomasi

2002

The Journal of Chemical Physics

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Ca 2ϩ aqueous solutions containing different proportions of ammonia have been studied by means of molecular dynamics simulations. Previously developed ab initio effective pair potentials, in the framework of the polarizable continuum model, and only tested at a cluster computation level, have been employed to describe ion-ligand interactions. Structural and dynamic changes present in the neighborhood of the ion as a function of the ammonia concentration have been followed. Results show a preferential solvation for ammonia, even at very low concentrations. For the pure aqueous solution, calcium ion is coordinated by eight water molecules, while the presence of ammonia favors an equilibrium between an octa and enna-coordinated situation when this ligand becomes predominant, confirming the prediction of cluster calculations. However, the increase in the coordination number is followed by an intrinsic loss of stability for the identifiable solvated structures because of the larger tendency of ammonia to participate in solvent exchange phenomena. Solvent exchange events show, for the most simple case ͑water-water exchange͒, a marked mechanistic variety.

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“…16 For the coordination numbers of Ca 2þ in liquid ammonia, early MC simulations reported 9 and 8.2, as observed from pair and pair plus threebody correction simulations, respectively. 61 No structural properties for this ion in aqueous ammonia solution have been reported so far and therefore they are the main subject of interest in this paper.…”

Section: Introductionmentioning

confidence: 99%

Preferential solvation of Ca2+ in aqueous ammonia solution: Classical and combined ab initio quantum mechanical/molecular mechanical molecular dynamics simulations

Tongraar

Sagarik

Rode

2002

Phys. Chem. Chem. Phys.

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Classical and combined quantum mechanical=molecular mechanical (QM=MM) molecular dynamics simulations have been performed to investigate the solvation structure of Ca 2þ in 18.4% aqueous ammonia solution. The classical molecular dynamics simulation has been carried out based on pairwise additive potentials. For the QM=MM scheme, the first solvation sphere of Ca 2þ is treated by Born-Oppenheimer ab initio quantum mechanics using LANL2DZ basis sets, while the rest of the system is described based on classical pairwise additivity. The results indicate the importance of the QM treatment in obtaining a reliable geometrical arrangement as well as the correct coordination number of the solvated ion. Within the first solvation sphere of Ca 2þ , the QM=MM simulation reveals a polyhedral structure with an average coordination number of 7.2, consisting of 5.2 water and 2 ammonia molecules, compared to the corresponding value of 9.7 composed of 6.7 water and 3 ammonia molecules obtained by classical pair potential simulation. The preference for ligands is discussed on the basis of detailed simulation results.

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Three-body Effects in Calcium(II)-ammonia Solutions: Molecular Dynamics Simulations

Cited by 11 publications

References 20 publications

Mg(II) and Ca(II) Microsolvation by Ammonia: Born–Oppenheimer Molecular Dynamics Studies

Mg(II) and Ca(II) Microsolvation by Ammonia: Born–Oppenheimer Molecular Dynamics Studies

Preferential solvation of Ca2+ in aqueous solutions containing ammonia: A molecular dynamics study

Preferential solvation of Ca2+ in aqueous ammonia solution: Classical and combined ab initio quantum mechanical/molecular mechanical molecular dynamics simulations

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