Infrared and dielectric studies of chloroform as proton donor in hydrogen-bond formation

Infrared absorption bands of free and associated species of deuterochloroform were observed in binary solutions (with triethylamine). Temperature-dependent spectra were used to calculate the equilibrium constants at various temperatures and the heat of formation of the complex molecule. A value of 0.133±3% liter mole-1 was obtained for the equilibrium constant at 25°C. The heat of formation of the deuterochloroform-triethylamine complex was determined to be 4.0 kcal mole -1. The dielectric constant shows a substantial increase over the value predicted by Onsager\u27s theory. This indicated that the associated complex possesses a large dipole moment. In conjunction with the infrared data, the dipole moment of the associated molecule was evaluated as 3.15×10 -18±10% cgs units. Similar infrared and dielectric measurements were carried out on deuterochloroform-acetonitrile mixtures. No strong hydrogen bonding was detected by either method