M. Tanabe, N. Kuze, H. Fujiwara
Dec 1, 1995
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Influential Citations
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Journal
Journal of Molecular Structure
Abstract
Abstract The molecular structure of 2-methylthiophene has been determined by gas electron diffraction combined with microwave spectroscopic data. Ab initio calculations at the HF 3-21 G ∗ level were carried out and used as an aid to the analysis. The torsional vibration of the methyl group was treated as a large-amplitude motion. A C 6 H bond was found to be cis with respect to the CC bond in the equilibrium state. The structural parameter values with estimated error limits (3σ) in parentheses are as follows: r g ( S C 2 ) = 1.729(1) A , r g ( C 2 C 3 ) = 1.374(3) A , r g ( C 2 C 6 ) = 1.505(5) A , r g ( C 5 H ) = 1.096(5) A , ∠CSC = 92.7(2)°, ∠SC 2 C 3 = 110.5(4)°, ∠SC 5 C 4 = 111.0(8)°, ∠SC 2 C 6 = 121.4(6)°, t = 4(5)° where t is the tilt angle which is defined to be the angle between the C 3 axis of the methyl group and the C 2 C 6 bond. The values of r (SC 2 ) − r (SC 5 ), r (C 2 C 3 ) − r (C 4 C 5 ), r (C 3 H) − r (C 5 H), r (C 4 H) − r (C 5 H), r( C 6 H ) − r( C 5 b H ) , ∠CCH, ∠SCH and ∠HCH were taken from the HF 3-21 G ∗ calculations.