Abstract: The reaction of [Ru₃(CO)₁₂ ] with dimer of p-methoxyphenyl thionophosphine sulfide in THFyields the novel trinuclear ruthenium carbonyl cluster [( μ-H)] 2Ru₃(CO)₉( μ₃-P)](Ⅰ) and tetranuclear ruthenium carbonyl cluster (Ⅰ) and tetranuclear ruthenium carbonyl cluster [Ru₄(CO)₁₀ ( μ₃-PC₆H₄OMe)](Ⅱ). These clusters were characterized by elemental analysis, IR, ¹H NMR, ³¹P NMRand MSspectrometric methods and the molecular structure of compound Ⅰ was determined by X-ray diffraction analysis. The molecular geometry of compound Ⅰ contains a trigonal pyramid Ru₃Pskeleton with a Ru₃ triangle at the base and the nude phosphorus atom as a 5e μ₃-Pbridging ligand at the apex. Though compound Ⅰ is one with 49 valence eletron, its Ru-Ru distances(average 0.2830 nm) are astonishly short and compound Ⅰ is rather stable in the exposure to oxygen and moisture. The structure of compound Ⅱ is believed to have a tetrahedral Ru₄ core which is attached to a μ₃ Sand a μ₃-PC₆H₄OMe ligand on tetrahedron's two triangular faces.

Key words: Ruthenium carbonyl cluster, Nude phosphorus atom, Phosphorus and sulfur ligands