Stability constant estimator user`s guide

Hay, Benjamin P.; Castleton, Karl J.; Rustad, James R.

doi:10.2172/475604

Cited by 3 publications

(3 citation statements)

References 30 publications

(42 reference statements)

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“…19,30 In these earlier studies, calculations on metal ion complexes of dimethoxyethane, DME, revealed that the degree of torsion angle change is related to the metal ion size. 19,30 In these earlier studies, calculations on metal ion complexes of dimethoxyethane, DME, revealed that the degree of torsion angle change is related to the metal ion size.…”

Section: Discussionmentioning

confidence: 98%

Structural Aspects of Rubidium Ion Selectivity by Tribenzo-21-crown-7¹^a

et al. 1998

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The structural origins of the selectivity of rubidium ion over other alkali metal ions by tribenzo-21-crown-7 is investigated from single-crystal X-ray diffraction: data for Cs(tribenzo-21-crown-7)(NO(3)), monoclinic, P2(1)/c, a = 9.598(2) Å, b = 23.466(3) Å, c = 23.973(5) Å, beta = 93.31(1) degrees, V = 5390(2) Å(3), Z = 8; data for [Rb(4,4'-bis-tert-butylbenzo,benzo-21-crown-7)(dioxane)(1.5)(H(2)O)(0.18)][Cl].(dioxane)1.82(H(2)O), triclinic, P&onemacr;, a = 11.687(3) Å, b = 12.800(4) Å, c = 17.680(3) Å, alpha = 75.31(2) degrees, beta = 80.01(2) degrees, gamma = 69.09(2) degrees, V = 2379.8(10) Å(3), Z = 2; data for Na(4,4'-bis-tert-butylbenzo,benzo-21-crown-7)ReO(4).0.5(i-PrOH), monoclinic, P2(1)/c, a = 24.300(5) Å, b = 14.066(3) Å, c = 22.676(5) Å, beta = 108.06(3) degrees, V = 7369(3) Å(3), Z = 8; data for and 4,4'-bis-tert-butylbenzo,benzo-21-crown-7, monoclinic, P2(1)/n, a = 16.427(2) Å, b = 11.3675(9) Å, c = 33.137(3) Å, beta = 94.469(8) degrees, V = 6169.0(10) Å(3), Z = 8. The structures reported here are the first reported for a tribenzo-21-crown-7, and the alkali metal ion complexes are the first reported structures of these ions with any 21-crown-7 ether. Different crown conformations are observed for each structure. Molecular mechanics calculations were performed on all conformers, and the results are related to the observed extraction selectivity for rubidium.

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Section: Discussionmentioning

confidence: 98%

Structural Aspects of Rubidium Ion Selectivity by Tribenzo-21-crown-7¹^a

et al. 1998

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“…Categories of empirical stability constant estimation approaches include those based on linear free energy relationships, properties of the metal ions, and parametric equations. 7 These parametric equations use such properties as charge, radii, and electronic structure. 8 There is a clear similarity of metal ion reactivity models with those of surface reactivity models.…”

Section: Introductionmentioning

confidence: 99%

“…Empirical methods are widely used to estimate unknown stability constants as well as demonstrate which molecular properties correlate with that reactivity. Categories of empirical stability constant estimation approaches include those based on linear free energy relationships, properties of the metal ions, and parametric equations . These parametric equations use such properties as charge, radii, and electronic structure .…”

Section: Introductionmentioning

confidence: 99%

Influence of Explicit Hydration Waters in Calculating the Hydrolysis Constants for Geochemically Relevant Metals

2010

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The effect of including a second, explicit solvation shell of water molecules is examined on the DFT calculation of a selection of aquo-metal ions' pK(a) values (deprotonation constants). Our goal is to gauge the accuracy of how certain cluster approximations and implicit solvation models (PCM or COSMO) affect the results. The ions in this study include: Al(3+)((aq)); Fe(3+)((aq)); Cr(3+)((aq)); Mn(3+)((aq)); Co(3+)((aq)); Ga(3+)((aq)); Fe(2+)((aq)); Mg(2+)((aq)); and Be(2+)((aq)). Overall, we find that experimental pK(a) constants can be calculated successfully to within 1-2 pH units, provided a consistent hydration structure is maintained for products and reactants.

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