Rearrangement of molybdocene tetraoxotetrasulfide Cp2MoS4O4 to Give [(Cp2MoS2H)2](HSO4)2: a novel proton-stabilized molybdocene disulfide dimer.

Cp(2)MoS(4), 1, in CH(2)Cl(2) undergoes extensive oxidation by m-CPBA at -78 degrees C to give a 1,1,4,4-tetroxide, 2 (59%). Tetraoxide 2 rearranges at room temperature to give an unusual sulfur-atom protonated molybdocene disulfide dimer [(Cp(2)MoS(2)H)(2)](HSO(4))(2), 3. Crystal data for 3 are P, a = 6.751(2) Angstroms, b = 9.865(4) Angstroms, c = 11.549(5) Angstroms, alpha = 109.95(3) degrees, beta = 96.11(3) degrees, gamma = 108.22(3) degrees, V = 666.9(4) Angstroms(3), and Z = 1. The dimer was also obtained directly when the oxidation was conducted at 0 degree C in DMF. Under basic conditions, the dimer is cleaved to give molybdocene disulfide Cp(2)MoS(2), while treatment of the latter with acid converts it to the dimer 3.