Eirik Røhmen, K. Hagen, R. Stōlevik
Mar 1, 1991
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0
Influential Citations
7
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract The molecular structure and conformational composition of 1,2-diiodoethane has been investigated using electron diffraction data. At 47°C the molecules exist in the gas-phase as a mixture of 88 (12)% anti and 12 (12)% gauche conformers with ICCI torsion angles of φ = 79 (16)° and φ = 180° for the gauche and anti conformers, respectively. Assuming that the two conformers differ in their geometries only in the torsion angle value, some of the important bond distances ( r g ) and valence angles (ǒ α ) obtained are: r (CC)= 1.479(33)A, r (CI)=2.166(15) A ǒCCI=110.2(12)°, ǒ(CCH=112.4(40)°, and ǒICH=105.2(47)°. Error limits are 2σ The observed conformational composition corresponds to an energy difference Δ E = E gauche - E anti = 2.0 ± 0.5 kcal mol −1 when estimated torsional wavenumbers of 77 cm −1 ( anti ) and 48 cm −1 ( gauche ) were included in the entropy difference; Δ S = 2.3±0.5 cal mol −1 K −1 .