CENTRO DE QUIMICA INORGANICA "DR. PEDRO J. AYMONINO"
Unidad Ejecutora - UE
Investigation of the gas-phase structure and rotational barrier of trimethylsilyl triﬂuoromethanesulfonate and comparison with covalent sulfonates
M. E. DEFONSI LESTARD; M. E.TUTTOLOMONDO; E. L. VARETTI; D. A. WANN; H. E. ROBERTSON; D. W. H. RANKING; A. BEN ALTABEF
JOURNAL OF MOLECULAR STRUCTURE
ELSEVIER SCIENCE BV
Año: 2010 vol. 984 p. 376 - 376
The molecular structure of trimethylsilyl tri.uoromethanesulfonate, CF3SO2OSi(CH3)3, has been determined in the gas phase from electron-diffraction data supplemented by ab initio (MP2) and DFT calculations using 6-31G(d), 6-311++G(d,p) and 6-311G++(3df,3pd) basis sets. Both experimental and theoretical data indicate that only one gauche conformer is possible by rotating about the OS bond. The anomeric effect is a fundamental stereoelectronic interaction and presents a profound influence on the electronic geometry. We have investigated the origin of the anomeric effect by means of NBO and AIM analysis. A natural bond orbital analysis showed that the lpp [O bonded to Si)] > s* [CS] hyperconjugative interaction favors the gauche conformation. In addition, comparison of the structural and stereoelectronic properties of the title molecule with those of silyl trifluoromethanesulfonate and methyl trifluoromethanesulfonate has been carried out.