NMR studies of solvent-solute interactions of OH,SH and CH protons in dimethyl formamide and dimethyl acetamide

The H-bonding of CH₃OH, C₆H₅SH and CHCl₃ with N:N Dimethyl formamide and N:N Dimethyl acetamide has been studied using proton magnetic resonance. It has been observed that the strength of interaction is greater for dimethyl acetamide than for dimethyl formamide for the same solvent. For the same solute, however, the strength increases in the order chloroform, thiol and alcohol. The equilibrium constant for 1:1 complex of these solutes in the chloroform solvent has been estimated. In the case of benzene thiol, complex formation between the pi-electrons of the phenyl ring and the amides has been detected. It has also been observed that the exchange rate of OH proton of CH₃OH in the dimethyl formamide decreases considerably.