New disulfido molybdenum-manganese complexes exhibit facile addition of small molecules to the sulfur atoms

The reaction of Mn₂(CO)₇(μ-S₂) (1) with [CpMo(CO)₃]₂ (Cp = C₅H₅) and [Cp*Mo(CO)₃]₂ (Cp* = C₅(CH₃)₅) yielded the new mixed-metal disulfide complexes CpMoMn(CO)₅(μ-S₂) (2) and Cp*MoMn(CO)₅(μ-S₂) (3) by a metal-metal exchange reaction. Compounds 2 and 3 both contain a bridging disulfido ligand lying perpendicular to the Mo-Mn bond. The bond distances are Mo-Mn = 2.8421(10) and 2.8914(5) Å and S-S = 2.042(2) and 1.9973(10) Å for 2 and 3, respectively. A tetranuclear metal side product CpMoMn₃(CO)₁₃(μ₃-S)(μ₄-S) (4) was also isolated from the reaction of 1 with [CpMo(CO)₃]₂. Compounds 2 and 3 react with CO to yield the dithiocarbonato complexes CpMoMn- (CO)₅[μ-SC(=O)S] (5) and Cp*MoMn(CO)₅[μ-SC(=O)S] (6) by insertion of CO into the S-S bond. Similarly, tert-butylisocyanide was inserted into the S-S bond of 2 and 3 to yield the complexes CpMoMn(CO)₅[μ-S(C=NBu^t)S] (7) and Cp*MoMn(CO)₅[μ-S(C=NBu^t)S] (8), respectively. Ethylene and dimethylacetylene dicarboxylate also inserted into the S-S bond of 2 and 3 at room temperature to yield the ethanedithiolato ligand bridged complexes CpMoMn- (CO)₅(μ-SCH₂CH₂S) (9), Cp*MoMn(CO)₅(μ-SCH₂CH₂S) (10), CpMoMn(CO)₅[μ-SC(CO₂Me)=C(CO₂Me)S] (11), and Cp*MoMn(CO)₅[μ-SC(CO₂Me)=C(CO₂Me)S] (12). Allene was found to insert into the S-S bond of 2 by using one of its two double bonds to yield the complex CpMoMn(CO)₅[μ-SCH₂C(=CH₂)S] (13). The molecular structures of the new complexes 2-7 and 9-13 were established by single-crystal X-ray diffraction analyses.