title: [1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazolidyl: a long-lived radical anion and its stable salts.
abstract: [1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazole (1) is synthesized in 62% yield by fluoride ion-induced condensation of 3,4-difluoro-1,2,5-thiadiazole with (Me(3)SiN=)(2)S. The reversible electrochemical reduction of 1 leads to the long-lived [1,2,5]thiadiazolo[3,4-c][1,2,5]thiadiazolidyl radical anion (2) and further to the dianion (3). The radical anion 2 is also obtained by the chemical reduction of the precursor 1 with t-BuOK in MeCN. The radical anion 2 is characterized by ESR spectroscopy in solution and in the crystalline state. The stable salts [K(18-crown-6)][2] and [K(18-crown-6)][2].MeCN (8 and 9, respectively) are isolated from the spontaneous decomposition of the [K(18-crown-6)][PhXNSN] (6, X = S; 7, X = Se) salts in MeCN solution followed by XRD characterization. The radical anion 2 acts as a bridging ligand in 8 and as chelating ligand in 9. The structural changes observed by XRD in going from 1 to 2 are explained by means of DFT/(U)B3LYP/6-311+G calculations.
authors.affiliation: Institute for Inorganic and Physical Chemistry, University of Bremen, Germany.
authors.forename: Alexander Yu
authors.initials: AY
authors.lastname: Makarov
authors.forename: Irina G
authors.initials: IG
authors.lastname: Irtegova
authors.forename: Nadezhda V
authors.initials: NV
authors.lastname: Vasilieva
authors.forename: Irina Yu
authors.initials: IY
authors.lastname: Bagryanskaya
authors.forename: Tobias
authors.initials: T
authors.lastname: Borrmann
authors.forename: Yuri V
authors.initials: YV
authors.lastname: Gatilov
authors.forename: Enno
authors.initials: E
authors.lastname: Lork
authors.forename: Ruediger
authors.initials: R
authors.lastname: Mews
authors.forename: Wolf-Dieter
authors.initials: WD
authors.lastname: Stohrer
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Zibarev