Synthesis and properties of mixed-metal phosphido and phosphinidene clusters derived from reaction between Ru"3(CO)"1"0(μ-H)(μ-PPh"2) and Cp^* Mo(CO)"3H - Wang, J.-C.; Chi, Y.; Peng, S.-M.; Lee, G.-H.; Shyu, S.-G.; Tu, F.-H. (Elsevier)
The tetranuclear phosphido cluster Cp^* MoRu"3(CO)"1"0(μ-H)"2(μ-PPh"2) (5) and the phosphinidene cluster Cp^* MoRu"3(CO)"1"0(μ"3-H) (μ"3-PPh) (6) have been synthesized by reaction of Ru"3(CO)"1"0(μ-H)(μ-PPh"2) with excess molybdenum hydride Cp^* Mo(CO)"3H in refluxing toluene solution. Crystals of 5 are monoclinic, space group P 2"1 with a = 10.708(2), b = 10.848(4), c = 14.885(2) Å, β = 97.63(2)^o, Z = 2, R = 0.021, R"w = 0.019 for 3025 observed reflections. The cluster has a tetrahedral array of metal atoms with one edge-bridging and one face-bridging hydride, and a phosphido ligand bridged across a basal Ru-Ru edge. Thermolysis of 5 under similar conditions produced the phosphinidene cluster 6 in high yield via elimination of a benzene molecule, indicating that 5 is an intermediate in the formation of 6. Subsequent treatment of 6 with CO caused fragmentation of the cluster affording a trinuclear phosphinidene cluster Cp^* MoRu"2(CO)"8(μ-H)(μ"3-PPh) (7). Dimerization of 7 occurred upon thermolysis to afford hexanuclear Cp"2^* Mo"2Ru"4(CO)"1"2(μ-PPh)"2 (8), which has also been characterized by X-ray diffraction. Crystal data of 8: space group C 2/c; a = 45.333(7), b = 10.185(2), c = 21.915(8) Å, β = 93.82(3)^o, Z = 8. The structure was solved by direct method and refined to R and R"w of 0.035 and 0.030 for 6135 observed reflections with I 〉 2σ-(I). The molecule adopts a square pyramidal MoRu"4 skeleton with a tentacle Mo atom bridging a Ru-Ru edge, on which the novel μ"4-η^2-CO ligand is associated with the butterfly Mo"2Ru"2 array; one μ"4-PPh ligand occupies a MoRu"3 square face and a second μ"3-PPh ligand caps a MoRu"2 face.
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