S. Leibowitz, J. Laane, C. Alsenoy
Aug 15, 1991
Citations
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Influential Citations
7
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract Ab initio calculations with full geometry optimization at the 4-21G level show that methyl cyanoacetate, NCCH 2 COOCH 3 , can exist as the cis (τ=0°) or as the gauche (τ= 145°) conformer, where τ measures the (N)CC(H 2 )CO dihedral angle. The cis is calculated to be 3.92 kJ mol −1 more stable than the gauche. Mid infrared spectra of the vapor and solid (77 K) phases and of solutions in liquid argon (80 K) along with Raman spectra of the liquid phase of the undeuterated molecule and of NCCH 2 COOCD 3 are reported and assigned. Asymmetric top contour simulations show that in the vapor phase the gauche form is the more stable of the two conformers observed. Low temperature Raman spectra of the liquid phase show that the enthalpy difference between the conformers is 2.46±0.2 kJ mol −1 , favoring the cis conformer.