THEORETICAL-STUDY OF PROTOTROPIC TAUTOMERISM AND ACIDITY OF TRIS(FLUOROSULFONYL)METHANE

The prototropic tautomerism and acidity of (FSO2)(3)CH was studied at both the semiempirical (PM3) and ab initio (HF/STO-3G and 3-21G*) lev el. It was shown that PM3 fails to describe the energetics of prototro pic tautomerism, while giving the geometry of the sulfo form in good a greement with the experimental data. The ab initio calculations predic t, in accordance with the experiment, that the sulfone form is more st able than the enol form. The conformity between calculated and experim ental geometry was also satisfactory. The gas phase acidity of (FSO2)( 3)CH was calculated and the factors which contribute to the extremely high gas phase acidity of the title compound were discussed.