MICROWAVE STUDIES OF THE 3 CONFORMERS OF BUTYL CYANIDE

Three conformers of n-butyl cyanide have been characterized by microwa ve spectroscopy. Low and medium resolution studies on static gas sampl es in Stark-modulated spectrometers revealed the presence of three con formational species and identified them. High resolution pulsed-jet Fo urier transform spectra allowed the assignment of individual transitio ns of each species yielding rotational and centrifugal distortion cons tants, N-14 quadrupole coupling constants, and qualitative relative en ergies of the species. The anti-anti and gauche(CN end)-anti forms are more stable than the anti-gauche(methyl end) conformer. The N-14 quad rupole coupling constants, which appear so different among the differe nt conformers, are consistent with a reference electric field gradient , that in methyl cyanide, rotated to the inertial axes of each conform er of butyl cyanide. (C) 1997 Elsevier Science B.V.