Synthesis, Characterization, and Reactivity of Alkyldisulfanido Zinc Complexes

The alkyldisulfanido zinc complexes Tp(iPr,iPr) n(SSR) and Tp(Ph,Me) n(SSR) where Tp(iPr,iPr) is hydridotris-((3,5-isopropyl) pyrazolyl)borate, Tp(Ph,Me) is hydridotris-((3-phenyl,5-methyl)pyrazolyl)borate, and (SSR) is tert-butyldisulfanido or triphenylmethanedisulfanido were synthesized by reaction between the corresponding hydroxo complexes Tp n(OH) and the synthetic persulfide RSSH. All the complexes were characterized by elemental analysis and H-1 NMR spectroscopy, and representative members of the class were also structurally characterized. The reactivity of the alkyldisulfanido Tp n(SSR) complexes with thiols was studied. In the absence of base, a simple exchange reaction between the alkyldisulfanido ligand and the thiol was observed in dichloromethane; when in the presence of base, the corresponding hydrogen(sulfido) complexes Tp n(SH) were obtained. The mechanism of the latter reaction has been studied and does not involve the coordinated alkyldisulfanido group. Reaction of the hydrogen(sulfido) complexes Tp(iPr,iPr) n(SH) with the thiosulfonate PhCH2S-SO2CF3 did not yield the expected alkyldisulfanido complex but benzyltrisulfide and a new complex tentatively assigned as Tp(iPr,iPr) n(O2SCF3).