Rotational barriers. 1. 1,2-dihaloethanes

Journal Article · Thu Jun 18 00:00:00 EDT 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100297a030· OSTI ID:6137651

Wiberg, K B; Murcko, M A

The rotational barrier about the C-C bond of 1,2-dichloroethane has been calculated by using several basis sets (4-31G, 6-31G*, 6-31+G*, and 6-31++G**) and including electron correlation. Corrections for zero-point energy differences, and the differences in enthalpy change from 0 to 298 K, were made by using the calculated geometries and vibrational frequencies. The trans/gauche energy difference was found to be 1.39 kcal/mol as compared to the observed value, 1.1 +/- 0.1 kcal/mol. The intramolecular interactions in the several rotamers are discussed. The trans/gauche energy difference for 1,2-difluoroethane also was calculated (MP3/6-311++G**) and was found to be 0.76 kcal/mol favoring the gauche conformer, again in good agreement with the experimental value of 0.57 +/- 0.09 kcal/mol. The trend in trans/gauche energy differences in the series n-butane, 1,2-dichloroethane, 1,2-difluoroethane is noted.

• Research Organization: Yale Univ., New Haven, CT
• OSTI ID: 6137651
• Journal Information: J. Phys. Chem.; (United States), Vol. 91:13
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CHLORINATED ALIPHATIC HYDROCARBONS
MOLECULAR STRUCTURE
ROTATIONAL STATES
ETHANE
FLUORINATED ALIPHATIC HYDROCARBONS
BOND ANGLE
BOND LENGTHS
ENTHALPY
GROUND STATES
LOW TEMPERATURE
MEDIUM TEMPERATURE
POTENTIALS
THEORETICAL DATA
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
ALKANES
DATA
DIMENSIONS
ENERGY LEVELS
EXCITED STATES
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
INFORMATION
LENGTH
NUMERICAL DATA
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
400201* - Chemical & Physicochemical Properties