N,N-dimethylformamide (DMF) is a polar aprotic solvent. It is “aprotic” because lacks any O-H or N-H bonds and is therefore incapable of being a hydrogen-bond donor with anions such as F(-) or Cl(-). Like DMSO, acetone, and acetonitrile it is relatively polar, with a dielectric constant of 38 and a dipole moment of 3.82 D. It is an excellent solvent for nucleophilic substitution reactions (SN2).