title: Ab initio HF, density functional and experimental studies on the IR spectra and structure of 1,2-benzisothiazol-3-(2H)-thione-1,1-dioxide (thiosacchanin) and its nitranion.
abstract: The spectral and structural changes taking place in the course of the conversion of 1,2-benzisothiazol-3-(2H)-thione-1,1-dioxide (thiosaccharin) into a nitranion have been studied on the basis of both IR spectra and ab initio HF 6-31G(d) and BLYP 6-31G(d,p) force field calculations. The conversion causes nu(as)SO2 and nu(s)SO2 frequency decreases of 47 and 13 cm(-1), respectively, and other spectral changes. The nuC=S coordinate is strongly delocalized. The ab initio geometries of the isolated molecule and nitranion agree well with the single-crystal X-ray ones, determined for thiosaccharin and its sodium (potassium) monohydrate salts, respectively. The nitranionic charge is delocalized almost uniformly within the thiocarbonyl (0.29 e-), sulfonyl (0.24 e-), and phenylene (0.24 e-) groups, and the nitranionic center (0.23 e-).
authors.affiliation: Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia. yb@orgchm.bas.bg
authors.forename: Y I
authors.initials: YI
authors.lastname: Binev
authors.forename: C T
authors.initials: CT
authors.lastname: Petkov
authors.forename: L
authors.initials: L
authors.lastname: Pejov
mesh_terms: D006858:Hydrofluoric Acid / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D008968:Molecular Conformation; D012439:Saccharin / Q000737:chemistry; D013055:Spectrophotometry, Infrared / Q000379:methods*; D013871:Thiones / Q000737:chemistry*
chemical_list: D007211:Indoles; D013871:Thiones; C418474:thiosacchanin; D012439:Saccharin; D006858:Hydrofluoric Acid