Reactions of tin(II) halides with [(π-C5H5)M(CO)3]2(M = Cr, Mo, and W)

Abstract

It is shown that, contrary to previous reports, the insertion of tin(II) halides, SnX₂(X = F, Cl, Br, or I), into the metal–metal bonds of the dimers [(π-C₅H₅)M(CO)₃]₂(M = Cr, Mo, or W) takes place on heating. As well as the [(π-C₅H₅)M(CO)₃]₂SnX₂ derivatives, the products may include the [(π-C₅H₅)M(CO)₃X] and [(π-C₅H₅)M(CO)₃SnX₃] complexes. The results are consistent with the availability of two pathways for these reactions. The first is ‘direct insertion’, the second is ‘indirect’, and proceeds via the [(π-C₅H₅)M(CO)₃SnX₃] compounds as detectable intermediates. The route adopted depends on both X and M, the reaction solvent, and the presence, or absence, of light. Many of these reactions also proceed smoothly at room temperatures, or somewhat above, on u.v. irradiation to give a similar range of products. Related reactions of the ‘mixed’ dimers [(π-C₅H₅)₂CrW(CO)₆] and [(π-C₅H₅)₂MoW(CO)₆] are described. The reactions between [(π-C₅H₅)M(CO)₃SnX₃] and [(π-C₅H₅)M′(CO)₃]₂(X = Cl, Br, or I; M, M′= Cr, Mo, or W) may be used to prepare [(π-C₅H₅)M(CO)₃][(π-C₅H₅)M′(CO)₃]SnX₂, and [(π-C₅H₅)Fe(CO)₂][(π-C₅H₅)M(CO)₃]SnX₂ may be similarly obtained.