The dimolybdenum alkyne complex [Mo2(μ-C2Ph2)(CO)4Cp2] 1 (Cp = η-C5H5), in which the alkyne ligand is perpendicular to the Mo–Mo bond, reacts with PriSH to afford two separable isomers of [Mo2(μ-η1,η1-C2Ph2)(μ-S)(μ-SPri)2Cp2] 2 in which the alkyne lies parallel to the Mo–Mo bond. In crystallographically characterised 2a the Pri substituents are both directed away from the alkyne ligand in a syn arrangement, creating a plane of symmetry, whereas in unsymmetrical 2b they are presumed to occupy an anti arrangement. Extended-Hückel molecular orbital
calculations show that the alkyne orientation in 2 results in better overlap between the alkyne and metal orbitals, as well as reduced repulsive interactions with the bridging thiolate ligands. Both isomers of 2 react with [Ru3(CO)12] to afford the same two products: the tetrahedral cluster [Mo2Ru2(μ3-C2Ph2)(μ3-S)(μ-SPri)2(CO)4Cp2] 7 in which the alkyne ligand remains parallel to the Mo–Mo edge, and trinuclear [Mo2Ru(μ-C2Ph2)(μ3-S)2(CO)3Cp2] 8 in which the alkyne has resumed its original perpendicular orientation; the crystal structures of both clusters are reported.
You have access to this article
Please wait while we load your content...
Something went wrong. Try again?