Synthesis of 1,10-Disulfanyl-closo-Decaborate Anion and Its Disulfonium Tetraacetylamide Derivative

A method has been proposed for the preparation of the 1,10-disulfanyl-closo-decaborate anion [1,10-B₁₀H₈(SH)₂]^2– (3). This compound can be easily prepared in several steps. The first step consists of selective incorporation of the iodide zwitterion at the apical vertices to the closo-decaborate anion 1,10-B₁₀H₈(IPh)₂ (1). At the second step, this group is replaced by thiodimethylformamide 1,10-B₁₀H₈(SCHNMe₂)₂ (2). At the last, third step, the thus-prepared derivative is subjected to hydrazinolysis at the substituted position to yield the 1,10-disulfanyl-closo-decaborate anion. This compound in its reactivity properties is very close to the equatorially substituted 2-sulfanyl-closo-decaborate anion [2-B₁₀H₉(SH)]^2–, which can easily enter an alkylation reaction in the presence of a base. Bromoacetamide was used as an example to prepare a disulfonium tetraacetylamide derivative of the closo-decaborate anion [1,10-B₁₀H₈(S(CH₂C(O)NH₂)₂)₂ (4)]. The prepared compounds were characterized by ¹¹B, ¹H, ¹³C multinuclear NMR spectroscopy, IR spectroscopy, and elemental analysis. The structures of compounds 2, 3, and 4 were determined by X-ray crystallography. Crystal packing and intermolecular interactions in compound 4 were characterized using X-ray diffraction data and Hirschfeld surface analysis.