INFLUENCE OF DIFFERENTLY SUBSTITUTED CYCLOPENTADIENYL LIGANDS ON CHEMISTRY OF ORGANOMETAL COMPLEXES WITH SULFUR

The reaction of the differently substituted cyclopentadienyl complexes L2M2(CO)4 with sulfur is investigated with respect to the ligand L (etmcp = ethyltetramethylcyclopentadienyl, tbcp = t-butylcyclopentadienyl, ipcp = isopropylcyclopentadienyl) and the metal M (Cr, Mo, W). For M = Cr the only isolated product is etmcp2Cr2S5. For M = Mo three isomers A, D, E of composition L2Mo2S4 (L = ipcp, etmcp) are formed whereas only two isomers (A, D) exist for L = tbcp. Only two isomers (D, E) of composition L2W2S4 are formed in the system L2W2(CO)4/S8, a further product is L2W2(CO)2S3 for L = etmcp. Structural characterisation of all compounds was achieved by IR, H-1, and Mo-95 NMR spectroscopy, whereas the structures of syn-etmcp2M2(mu-S)2S2 (M = Mo, W) were determined by X-ray crystallography, the result of which allows the correction of a previous structure assignment. It is further shown that a thermal equilibrium exists between L2Mo2(mu,eta-2-S2)(mu-S)2 (A) and syn-L2Mo2(mu-S)2S2 (D) which depends strongly on the ligands.