R. Knudsen et al., A LOW-TEMPERATURE MATRIX-ISOLATION INFRARED STUDY OF ACETAMIDES .2. THIOACETAMIDE AND SOME DEUTERATED DERIVATIVES, Journal of molecular structure, 321(3), 1994, pp. 197-203
The IR spectra of thioacetamide and some deuterated derivatives isolat
ed in an argon matrix (14 K) are reported. In comparison with acetamid
e the CN torsional barrier and the frequencies of the NH2, CH3 and CN
stretchings are explained by the influence of the chalcogen atom on th
e relative weights of resonance structures in the valence bond scheme.
The calculated value of the CN barrier of 128 kJ mol-1 is found to be
larger than that obtained for acetamide, 81 kJ mol-1. The results are
in good agreement with those reported from NMR measurements for solut
ions and the trend is contrary to that obtained from solid state IR fr
equencies.