“Ionic liquid ([bmim][PF6] or [bmim][BF4]) + molecular solvent. New solvents designed on the basis of the microscopic properties of the binary mixtures.”

MANCINI PM, ADAM CG, FORTUNATO, GG, VOTTERO LR.

Florianópolis. Brasil

Conferencia; 8th Latin Conference on Physical Organic Chemistry.; 2005

On the last few years designing solvents has become an important task for chemists. The challenge consists on developing a “desired solvent” with a particular  use in mind. Ionic liquids are attracting increasing attention as a new class of solvents for a wide range of applications. The combination of anions and cations can give rise to a great number of potential ionic liquids. From the combination of pure solvents in binary mixtures, the availability and diversity of media were strongly increased. In the present work we investigate solvent systems which result from the basis of binary solvent mixtures formed by an ionic liquid and a molecular solvent. The ionic liquids selected are composed by 1-butyl-3-methylimidazolium as cation and hexafluorophosphate and tetrafluoroborate as anions. The molecular solvents included in the analysis are dimethylsulfoxide, acetonitrile and methanol. The mixed-solvent features are related with its most relevant microscopic properties which determine how it will interact with potential solutes. The p*, b and a (Kamlet, Abboud and Taft) and SPP, SB and SA (Catalán and coworkers) scales were selected to quantify the properties at a molecular level of the investigated ionic liquid/molecular solvent systems. The behavior of the explored solvent systems are analyzed according to the response patterns property vs mixture composition focusing on the changes in the ability to develop the most relevant interactions, paying particular attention to pronounced changes in the microscopic solvent features. Additionally, taking into account that the selected multiparametric approaches measure the solvent descriptors from different solvatochromic reference probes, the linear correlation and the agreement between paired values are investigated. In conclusion, we propose individual solvent mixtures of particular compositions as “new solvents” with selected solvation properties, and in order to evaluate these “new solvents” as a reaction media, the kinetics of nucleophilic aromatic substitution reactions was studied.