G. Serboli, B. Minasso
Jul 1, 1971
Citations
0
Influential Citations
2
Citations
Journal
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Abstract
Abstract A theoretical study on 1-chlorotetrafluoro-2-iodoethane and 1-bromotetrafluoro-2-iodoethane has been undertaken to calculate the conformational potential energy as a function of the internal rotation angle. The results have shown that one “trans” and two equivalent “gauche” forms are present. A scrutiny of the i.r. spectra of these compounds measured in the vapour, liquid and a solid phase, has led to the identification of the bands belonging to the more stable isomers and to the less stable one. The energy difference between the two forms in the vapour phase, as determined experimentally, is 870 cal mole for 1-chlorotetrafluoro-2-iodo-ethane and 1150 cal mole for 1-bromotetrafluoro-2-iodoethane, while the theoretical values are 960 cal mole and 1240 cal mole respectively. For the compounds CF 2 X -CF 2 Y , where X . and Y are Cl, Br, and I in all the possible combinations, there is an exponential relationship between the values of Δ H exp o and those of the sum of the van der Waals radii of X and Y .