Polar Aprotic Solvents : Aprotic solvents are those sovents whose moelcules do not have a hydrogen atom that is attached to an atom of an electronegative element. A number of polar aprotic solvents have come into wide use by chemists because they are espcially useful in `S_(N^(2))` reactions . Several examples are the followning :
All of these solvents (DMF,DMSO, and HMPA) dissolve ionic compounds, and they, solvate cations very welll. They do so in the same way that protic solvents cations: by orienting their negative ends around the cation and by donating unshared electron pairs to vacant orbitals of the cation :
