I. Tokue, T. Fukuyama, K. Kuchitsu
Oct 1, 1974
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0
Influential Citations
36
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract The structures of isobutene and 2,3-dimethyl-2-butene have been studied by gas electron diffraction. For isobutene the rotational constants obtained by Laurie by microwave spectroscopy have also been taken into account. Leastsquares analyses have given the following r g bond distances and valence angles ( r av for isobutene and r α for dimethylbutene): for isobutene, r (CC) = 1.342±0.003 A, r (C-C)= 1.508±0.002A, r (C-H, methyl) = 1.119±0.007 A, r(C-H, methylene) = 1.095±0.020 A, ∠(C-CC) = 122.2±0.2°, ∠(H-C-H) = 107.9±0.8°, and ∠(C-C-H) 121.3±1.5°; for dimethylbutene, r (CC)= 1.353 ±0.004 A, r (C-C) = 1.511±0.002 A, r (C-H) = 1.118± 0.004 A, ∠(C-CC)= 123.9±0.5°, and ∠(H-C-H)= 107.0±1.0°, where the uncertainties represent estimated limits of experimental error. The bond distances and valence angles in these molecules and in related molecules are compared with one another. The CC and C-C bond distances increase almost regularly with the number of methyl groups, and the C-C bonds in isobutene and dimethylbutene are shorter than those in acetaldehyde and acetone by about 0.01 A. Systematic variations in the C-CC angles suggest the steric influence of methyl groups.