title: EPR studies on the thiophenodithiazolyl radical, C4H2S3N.
abstract: Selective chlorination of thiophene-2,3-dithiol with SO(2)Cl(2) generates the corresponding sulfenyl chloride, 2,3-C(4)H(2)S(SCl)(2). Subsequent condensation with Me(3)SiN(3) yields the thiophenodithiazolylium salt [C(4)H(2)S(3)N]Cl, [TDTA]Cl. The structure of the cation, TDTA+, was established by X-ray diffraction as both its AsF(6)(-) and HSO(4)(-) salts. Reduction of [TDTA]Cl with Ag powder yields the radical TDTA* which was characterised by X- and Q-band (9 and 34 GHz) EPR and ENDOR studies. The spin density distributions estimated from the EPR/ENDOR measurements were found to be in very good agreement with those determined by DFT (B3LYP/6-31G*) indicating that ca 10% of the spin density is delocalised onto the thiophene ring. Comparison of the spin density distributions in TDTA* and the isoelectronic trithiatriazapentalenyl radical C(2)S(3)N(3), TTTA*, indicates that replacement of N by C-H leads to a localisation of the spin density on the dithiazolyl ring.
authors.affiliation: Department of Chemistry, The University of Cambridge, Lensfield Road, Cambridge, UKCB2 1EW.
authors.forename: Antonio
authors.initials: A
authors.lastname: Alberola
authors.forename: Robert D
authors.initials: RD
authors.lastname: Farley
authors.forename: Simon M
authors.initials: SM
authors.lastname: Humphrey
authors.forename: Gordon D
authors.initials: GD
authors.lastname: McManus
authors.forename: Damien M
authors.initials: DM
authors.lastname: Murphy
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Rawson