G. Raabe, Andrea Gais, J. Fleischhauer
May 15, 1996
Citations
0
Influential Citations
54
Citations
Journal
Journal of the American Chemical Society
Abstract
Ab initio calculations of the (methylsulfonyl)methyl anion (1), the ((trifluoromethyl)sulfonyl)methyl anion (1T), the (fluorosulfonyl)methyl anion (1F), and the (methylsulfonyl)isopropyl anion (1D) at the HF/6-31+G*//HF/6-31+G* level revealed a significant effect of fluorine substitution upon the structure and energy of α-sulfonyl carbanions. The Cα−S bond in 1T and 1F is shorter and the pyramidalization of the anionic carbon atom is less than in 1. In the anions 1T and 1F the Cα−S bond is shortened and the S−CF3(F) and the S−O bonds are lengthened as compared to the sulfones 3T and 3F. For all anions the staggered conformation (1, 1T, 1F, 1D) is energetically more stable than the eclipsed conformation (2, 2T, 2F, 2D). At the MP2/6-31+G*//HF/6-31+G* level the energy difference between the staggered and the eclipsed conformation is much larger for the fluorinated anions 1T and 1F than for 1 and 1D. The rotational barriers about the Cα−S bond of the fluorinated species 1T and 1F are in accordance with relat...