No abstract

The solvation structures of tetraethylammonium bromide and tetrafluoroborate (TEABr and TEABF 4 ) in aqueous binary solvents with ethanol (EtOH), 2,2,2trifluoroethanol (TFE), and acetonitrile (AN) have been clarified by molecular dynamics (MD) simulations. In addition, 1 H and 13 C NMR chemical shifts of the H and C atoms within TEA + in the binary solvents have been measured as a function of the mole fraction of the organic solvent, x OS . The variations of the chemical shifts with an increase in x OS were interpreted according to the solvation structures of TEA + , Br − , and BF 4 − obtained from the MD simulations. It has been found that TEABF 4 at 130 mmol dm −3 cannot be dissolved into the EtOH and TFE solvents above x OS ≈ 0.7 and 0.6, respectively, while TEABr can be done in both solvents. Interestingly, TEABr and TEABF 4 at the concentration can be dissolved in the AN solvents over the entire x OS range. The solvation of TEA + , Br − , and BF 4 − in each solvent has been discussed in terms of the electrostatic force, the weak hydrogen bond of C−H•••F− C, and the dipole−dipole interaction.