Dipole moments of thiophene analogs of chalcones and their vinylogs |
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Authors: | S V Tsukerman V M Nikitchenko V D Orlov V F Lavrushin |
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Institution: | 1. Gorkii Khar'kov State University, USSR
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Abstract: | The dipole moments of 25α, β unsaturated ketones of the thiophene series are measured in benzene at 25°, and their most probable coplanar conformations established. For the systems studied it is shown that, in the static state, the 2-thienyl group exhibits an electron-donating effect, greater than those of 2-furyl and phenyl. Introduction of electron-donating and electron-accepting substituents into the molecule of 1-(thienyl-2)-3-phenylpropenones as well as shift of the carbonyl group away from the aryl one towards the heterocyclic ring, leads in general to an increase in dipole moment. A linear relationship is found for the changes in dipole moment of isomeric thiophene ketones due to electron-donating substituents. Dipole moments of propen-3-ones correlate satisfactorily with Hammett σ parameters for substituents, and intermolecular distances. |
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