Theoretical study of anion binding to calixpyrrole: the effects of solvent, fluorine substitution, cosolute, and water traces.
|Title||Theoretical study of anion binding to calixpyrrole: the effects of solvent, fluorine substitution, cosolute, and water traces.|
|Publication Type||Journal Article|
|Year of Publication||2002|
|Authors||J Blas, Ramón, Márquez Manuel, Sessler Jonathan L., F Luque Javier, and Orozco Modesto|
|Journal||J Am Chem Soc|
|Date Published||2002 Oct 30|
|Keywords||Anions, Calixarenes, Computer Simulation, Fluorinated, Hydrocarbons, Models, Molecular, Porphyrins, Pyrroles, Quantum Theory, Solvents, Thermodynamics, Water|
The binding of different anions to calixpyrrole has been studied by means of molecular dynamics coupled to thermodynamic integration calculations. The effect of different apolar solvents, octafluoro substitution, and the change in binding free energy derived from the presence of cosolute and water traces (the hydrated salt used to introduce the anion in the solution) were examined. Calculations allow us to rationalize the differential binding of ions to calixpyrrole and octafluorocalixpyrrole as well as to predict the behavior in new solvents for which experimental data are not available yet. It is found that both calixpyrrole and octafluorocalixpyrrole have a dramatic preference for F- in the gas phase and pure aprotic solvents, but the situation can change dramatically in protic solvents or in the presence of the hydrated cation which is used as cosolute of the anion. Overall, our results provide interesting clues for a better understanding of the process detected experimentally as "binding".