Theoretical, structural, vibrational, NMR, and thermal evidence of the inter- versus intramolecular hydrogen bonding in oxamides and thiooxamides

Desseyn HO; Perlepes SP; Clou K; Blaton N; Van der Veken BJ; Dommisse R; Hansen PE

Journal of Physical Chemistry A, Vol.108, No.24, 5175-5182, 2004

Desseyn HO, Perlepes SP, Clou K, Blaton N, Van der Veken BJ, Dommisse R, Hansen PE

This contribution describes the study of hydrogen bonding in secondary oxamides, monothiooxamides, and dithiooxamides by ab initio calculations, X-ray diffractions, NMR spectra, thermal analysis, and variable-temperature infrared and Raman spectroscopy. The results can all be interpreted as a function of the change in the strength and the nature of the hydrogen bonding by substituting oxygen for sulfur in the series CH3-HNCOCONHCH3, CH3HNCSCONHCH3, CH3HNCSCSNHCH3 and by changing the steric influence of the alkyl group in a series of oxamides (RHNCOCNHR; R = CH3, C2H5, iC(3)H(7), tC(4)H(9)).