Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 50. Synthesis and crystal structures of the complexes [RuW3(µ-CO)(µ3-η-CO)(µ-CPh)2(µ3-CPh)(CO)2(η-C5H5)3] and [RuW3(µ-CO)(µ3-η-CO){µ-C(Ph)C(O)}(µ-CPh)(µ3-CPh)(CO)(PMePh2)(η-C5H5)3]