Dinuclear molybdenum complexes containing the novel mu,eta(1 : 3)-AsS2 ligand: synthesis and molecular structure of [{(Cp2Mo2)-Mo-*(CO)(2)As2S4}center dot 2Cr(CO)(5)]center dot 0.5CH(2)Cl(2) (Cp*=C5Me5)

The reaction of [Cp*Mo(CO)(3)Cl] (Cp* = C5Me5) with K3AsS3 has been investi gated under different conditions. At 56 degreesC, the already known compoun ds [(Cp2Mo2S4)-Mo-*] (2), [(Cp2Mo2As2S3)-Mo-*] (3), and [(Cp2Mo2S4H2)-Mo-*] (4) are formed along with [(Cp2Mo2)-Mo-*(CO)(2)As2S4] (5). Reaction at 120 degreesC only gives 2 and 3. Complex 5 was characterized by means of its b isadduct [{(Cp2Mo2)-Mo-*(CO)(2)As2S4}. 2Cr(CO)(5)] (6). An X-ray crystallog raphic study of 6 reveals the presence of two novel Ass, ligands, bridging in a pseudoallylic manner two Mo atoms. The Cr(CO), fragments are coordinat ed to both the outer sulfur atoms. Thus, each AsS2 ligand in 6 acts as a se ven-electron ligand. (C) 2001 Elsevier Science B.V. All rights reserved.