Polysulfido Chain in Binuclear Zinc(II) Complexes

The synthesis and a detailed reactivity study of a binuclear zinc(II) bis(benzenethiolate) complex, [Zn2(BPMP)(SPh)2]+(4), and anunprecedented binuclear zinc(II) pentasulfido complex, [Zn2(BPMP)(mu 2-S5)]+(6), are presented. While one-electron oxidation of the coordinatedbenzenethiolate ligands in4by Cp2Fe+produces diphenyl disulfide and[Zn2(BPMP)(mu 2-OH)]2+(5), a two-electron redox reaction betweencoordinated benzenethiolate ligands in4and elemental S (S8) generateddiphenyl disulfide and the binuclear zinc(II) pentasulfido complex6.Complex6features a chelating, dianionic, pentasulfido (S52-) chain andcan consume up to a maximum of 3 equiv of PPh3to generate Ph3PS and5, while the reaction of6with 1 equiv of diphenylphosphinoethane allowed the isolation of [Zn2(BPMP)(mu 2-S4)]+(7). A proteolysisreaction of the coordinated S52-chain in6withfluoroboric acid (HBF4), benzoic acid (PhCOOH), and thioacetic acid (MeCOSH)generates the complexes [Zn2(BPMP)(MeCN)2]3+(1), [Zn2(BPMP)(mu 2-PhCOO)2]+(8), and [Zn2(BPMP)(mu 2-SCOMe)2]+(9),respectively, while the protonated S52-chain liberates S8and hydrogen sulfide (H2S). Finally, the transfer of the coordinatedbenzenethiolate ligands in4and the S52-chain in6to selected organic compounds, namely, PhCH2Br and PhC(O)Cl, for the generation of various organosulfur compounds is demonstrated

Automated summary

The synthesis and reactivity of a binuclear zinc complex and an unprecedented binuclear zinc pentasulfido complex were studied. The reaction produced various sulfur compounds through oxidation-reduction reactions. The coordinated ligands and chains in the complexes can be used as catalysts to generate organic sulfur compounds.