R. Alder, Paul R. Allen, D. Hnyk
May 19, 1999
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Influential Citations
17
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Journal
Journal of Organic Chemistry
Abstract
The molecular structure of 3,3-diethylpentane (tetraethylmethane) in the gas phase has been determined by electron diffraction and ab initio calculations at the MP2/6-31G* level. Five local minima on the potential energy surface were located, but only two have significant populations at room temperature. The experimental distribution of conformers was found to be 66(2)% with D2d symmetry and 34(2)% with S4 symmetry, corresponding to an energy difference ΔH° in favor of the D2d form of 3.3(2) kJ mol-1. The molecule shows significant distortion from regular tetrahedral coordination at the central carbon atom, with two CCC angles in the D2d form reduced to 106.7(8)° and two angles in the S4 form increased to 110.9(4)°. These distortions are attributed to asymmetry of the electron density distribution around the CH2 groups.