[1,2,5]Selenadiazolo[3,4-c][1,2,5]thiadiazole and [1,2,5]Selenadiazolo[3,4-c][1,2,5]thiadiazolidyl - A Synthetic, Structural, and Theoretical Study

A new heterocyclic system, namely [1,2,5]selenadiazolo[3,4‐c][1,2,5]thiadiazole (1), has been prepared in 60 % yield by the 1:1 condensation of 3,4‐diamino‐1,2,5‐thiadiazole (4) with SeCl4 in the presence of pyridine. The structures of 1 and its 1:1 complex with pyridinium chloride (5) have been elu...

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Bibliographic Details
Published in:European Journal of Inorganic Chemistry 2007-10, Vol.2007 (30), p.4751-4761
Main Authors: Bagryanskaya, Irina Yu, Gatilov, Yuri V., Gritsan, Nina P., Ikorskii, Vladimir N., Irtegova, Irina G., Lonchakov, Anton V., Lork, Enno, Mews, Ruediger, Ovcharenko, Victor I., Semenov, Nikolay A., Vasilieva, Nadezhda V., Zibarev, Andrey V.
Format: Article
Language:English
Subjects:
Density functional calculations
Magnetic properties
Nitrogen heterocycles
Radical anions
Selenium
Sulfur
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Summary:A new heterocyclic system, namely [1,2,5]selenadiazolo[3,4‐c][1,2,5]thiadiazole (1), has been prepared in 60 % yield by the 1:1 condensation of 3,4‐diamino‐1,2,5‐thiadiazole (4) with SeCl4 in the presence of pyridine. The structures of 1 and its 1:1 complex with pyridinium chloride (5) have been elucidated by X‐ray diffraction (XRD). The reversible electrochemical reduction of 1, as well as its chemical reduction with PhS– anion, provide the long‐lived [1,2,5]selenadiazolo[3,4‐c][1,2,5]thiadiazolidyl radical anion (2), which has been isolated in the form of the thermally stable salt [K(18‐crown‐6)][2] (3) in 75 % yield. The experimental structural and spectral characteristics of 1 and 2 agree fairly well with those obtained from density functional (DFT) calculations. The salt 3 has been characterized by ESR spectroscopy (in the solid state and in solution) and XRD. The radical anion 2 acts as a bridging ligand in crystalline 3. Magnetic measurements on salt 3 reveal weak antiferromagnetic interactions (J = –1.65 cm–1). The magnetic structures of 3 and its disulfur congener 11 have been analyzed in terms of dimeric exchange integrals calculated by spin‐unrestricted broken‐symmetry DFT and post‐HF methods.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
ISSN:1434-1948
1099-0682
DOI:10.1002/ejic.200700501