NEAR-INFRARED SPECTROSCOPIC STUDIES OF THE HYDROGEN-BONDING BETWEEN THIOACETAMIDE AND N,N-DISUBSTITUTED BENZAMIDE DERIVATIVES IN CCL4

The hydrogen bonding interactions between thioacetamide (TA) and sever al N,N-disubstituted benzamides (N,N-dimethylbenzamide (DMBA), N-metho xy-N-methylbenzamide (MMBA), N,N-diethyl-m-toluamide (DEMT), and N,N-d iethyl-2,5-difluorobenzamide (DEDF)) have been studied using near-infr ared absorption spectroscopy. Thermodynamic parameters for the interac tions between TA and benzamides were determined by analyzing the v(N-H )(35) + amide II combination band of TA. The -Delta H-0 values, indica ting the intrinsic strength of hydrogen bonding, are -17.4, -21.6, -21 .9 and -20.8 kJ mol(-1) for DMBA, MMBA, DEMT and DEDF, respectively. T he results show that the inductive and resonance effects of substituen ts appear to influence the formation of hydrogen bonds.