Conformational stability of the haloacetyl halides
- 1 October 1990
- journal article
- research article
- Published by Taylor & Francis in International Reviews in Physical Chemistry
- Vol. 9 (4) , 349-379
- https://doi.org/10.1080/01442359009353251
Abstract
The far-infrared spectra of a series of haloacetyl halides, CH2XC(O)X, in the vapour phase have been recorded at a resolution of 0-10cm−1 in the 350-35 cm−1 region. The fundamental asymmetric torsional frequencies of the more stable trans (two halogen atoms oriented trans to one another) and high-energy conformers have been observed. From these data the asymmetric torsional potential functions governing internal rotation about the C-C bond have been determined. Only fiuoroacetyl fluoride and fluoroacetyl chloride have the cis conformation for the high-energy form whereas all the other haloacetyl halides have the gauche conformation for the high-energy form. For those molecules in this series which have the gauche form as the high-energy rotamer the importance of using the value for the torsional dihedral angle in the determination of the potential function governing internal rotation is reviewed. It is shown how complete equilibrium geometries, which have been determined by ab initio Hartree-Fock gradient calculations, can be used in conjunction with microwave and/or electron diffraction studies to obtain more reliable experimental structural parameters for these molecules. Finally, the reliability of the ab initio techniques used at predicting trends in the optimized geometries and potential functions governing internal rotation are assessed.Keywords
This publication has 23 references indexed in Scilit:
- Conformational stability, barriers to internal rotation, normal coordinate analysis, and vibrational assignment of chloroacetyl bromideStructural Chemistry, 1990
- Conformational analysis, barriers to internal rotation, ab initio calculations and vibrational assignment of fluoroacetoneSpectrochimica Acta Part A: Molecular Spectroscopy, 1989
- Conformational analysis and structural determinations from ab initio calculations for chloroacetaldehydeJournal of Molecular Structure: THEOCHEM, 1989
- Conformational stability, barriers to internal rotation and vibrational assignments of fluoroacetyl bromideChemical Physics, 1989
- Conformational stability, barriers to internal rotation, ab initio calculations and vibrational assignment of fluoroacetyl fluorideJournal of Molecular Structure, 1989
- Conformational stability, barriers to internal rotation, vibrational assignment and a b i n i t i o calculations of fluoroacetyl chlorideThe Journal of Chemical Physics, 1989
- Conformational stability, barriers to internal rotation, vibrational assignment, and a b i n i t i o calculations of chloroacetyl fluorideThe Journal of Chemical Physics, 1988
- A b i n i t i o study of the methyl internal rotation of acetaldehyde in the S1 (n ,π*) stateThe Journal of Chemical Physics, 1985
- Low frequency vibrational spectra, methyl torsional potential functions, and internal rotational potential of propanalThe Journal of Chemical Physics, 1980
- The microwave spectrum of chloroacetaldehydeThe Journal of Chemical Physics, 1976