V. Gibon et al., MOLECULAR-STRUCTURE AND ELECTRONIC-PROPERTIES OF A 1-SULFONYLINDOLIZINE DERIVATIVE, 2-ISOPROPYL-1-METHYLSULFONYLINDOLIZINE, Acta crystallographica. Section C, Crystal structure communications, 50, 1994, pp. 1749-1753
For the title compound, C12H15NO2S, both the crystallographic data and
theoretical results (ab initio molecular-orbital calculations) indica
te a stabilization of the symmetrical conformation of the sulfone grou
p with respect to the indolizinic bicycle. The crystal packing and the
topology of the frontier orbitals clearly suggest a charge-transfer p
rocess from the five-membered ring towards the six-membered ring of th
e indolizine for two adjacent molecules.