Solvation and free energies

These two functions are not truly independent parameters, since both correlate with the compound s log P value. Indeed, Log BB has also been calculated using PSA alone, as well as several other solvation and free energy methods. - " After Young showed that experimental Log P values could be correlated with experimental Log BB data algorithms were developed to calculate Log BB based on tPSA and c Log P (c Log P is a computed Log P value, based on a calculation of the contributions of the individual atoms and fragments in a molecule to its overall partition coefficient). ... 

Table 2. Heat of solvation and free energy of solvation of alkali ions and alkaline earth ions...

Lynden-Bell R M and Rasaiah J C 1997 From hydrophobic to hydrophilic behavior a simulation study of solvation entropy and free energy of simple solutes J. Chem. Phys. 107 1981... 

It is possible to detemiine the equilibrium constant, K, for the bimolecular reaction involving gas-phase ions and neutral molecules in the ion source of a mass spectrometer [18]. These measurements have generally focused on tln-ee properties, proton affinity (or gas-phase basicity) [19, 20], gas-phase acidity [H] and solvation enthalpies (and free energies) [22, 23] ... 

Parker, A. J., Solvation of ions—enthalpies, entropies and free energies of transfer, Electrochim. Acta, 21, 671 (1976). 

Cornell, W. D. Cieplak, P. Bayly, C. I. Kollman, P. A., Application of RESP charges to calculate conformational energies, hydrogen bond energies, and free energies of solvation, J. Am. Chem. Soc. 1993,115, 9620-9631. 

The gas-phase lifetime of N20- is 10-3 s in alkaline solutions, it is still >10-8 s. Under suitable conditions, N20- may react with solutes, including N20. The hydrated electron reacts very quickly with NO (see Table 6.6). The rate is about three times that of diffusion control, suggesting some faster process such as tunneling. NO has an electron affinity in the gas phase enhanced upon solvation. The free energy change of the reaction NO + eh (NO-)aq is estimated to be --50 Kcal/mole. Both N02- and N03- react with eh at a nearly diffusion-controlled rate. The intermediate product in the first reaction, N02-, generates NO and... 

Figure 19 summarizes the geometric and free energy characteristics of the reactions investigated. The free energies, G, were calculated at the UHF-MP2 level and include the contribution of solvation. 

Figure 11.11 Thermodynamic relationship between partitioning free energies and free energies of solvation. Knowledge of any two free energies permits prediction of the third since any cycle around the free-energy triangle must sum to zero...

S. E. Debolt and P. A. Kollman. Investigation of structure, dynamics, and solvation in 1-octanol and its water-saturated solution - molecular-dynamics and free-energy perturbation studies. J. Am. Chem. Soc., 117(19) 5316—5340, 1995. 

Crown ethers continue to be one of the most useful parts of supramolecular chemistry/91 From the beginning computations of metal ions complexes with synthetic ionophores/101 which have been aptly reviewed/111 emphasized the importance of including explicitly solvation in free energy calculations, also with ab initio calculations on calixarene complexes/121 Molecular dynamics simulations of 18-crown-6 ether complexes in aqueous solutions predict too low affinities, but at least correctly reproduce the sequence trend K+ > Rb+ > Cs+ > Na+. However, only the selection of K+ over Rb+ and Cs+ is ascribed to the cation size relative to that of the crown cavity, whereas K+ appears in these calculations to be selected over Na+ as consequence of the greater free energy penalty involved in displacing water molecules ftomNa/1131... 

C. S. Pomelli and J. Tomasi, Variation of surface partition in GEPOL effects on solvation free energy and free-energy profiles, Theor. Chem. Acc., 99 (1998) 34-43. 

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