Spectroscopic Evidence of Hydrogen Bonds: Chloroform and Bromoform in Donor Solvents

The method of infra-red spectroscopy has been used to study solutions of chloroform and bromoform in various electron donor solvents, including ketones, esters, ethers and amines. In the region of 4μ, a band has been observed which apparently is not characteristic of the spectrum of either the solute or solvent. Because of the intensity of the band it is thought to be a fundamental. The most reasonable interpretation seems to be that it is an NH or OH vibrational band resulting from intermolecular hydrogen bond formation between the CH haloform group and a N or O of the solvent. The band for the bromoform solutions is weaker than that for the corresponding chloroform solutions.