K. Hagen
Jul 1, 1986
Citations
0
Influential Citations
4
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract Thiophene-2-carbonyl chloride has been investigated by electron diffraction from the gas at a nozzle temperature of 363 K. The more stable of the two conformers identified is the planar form with the carbonyl oxygen and the sulfur atom of the thiophene ring syn to each other; the less stable conformer is the planar (or near planar) anti form. Assuming that the only geometrical difference between the two forms is their SCCO torsion angle and assuming the thiophene ring to have C 2V symmetry, the results for the most important distances ( r a -values) and angles (∠ α ) are: r (CH) = 1.070(38) A, r (CO) = 1.194(7) A, r (CC) = 1.380(11) A, r (CC) (in the ring) = 1.410(23) A, r (CCOCl) = 1.475(20) A, r (CS) = 1.713(6) A, r (CCl) = 1.796(11) A, ∠C=CCOCl = 127.0(1.6)°, ∠CCS = 112.2(8)°, ∠CCH = 131.0(8.2)°, ∠CCO = 126.5(1.3)°, ∠CCCl = 112.9(1.2)°, ∠CSC = 91.4(7)°; the quantities in parentheses are estimated 2 σ values. At 363 K the observed proportion of the conformer with S and O syn is 59(11)%, and the syn conformer has a r.m.s. torsional amplitude of τ = 20.6(6.7)°. The remaining vibrational amplitudes are calculated from an assumed force field. The results are compared with those for related thiophene and furan compounds.