Reaction of bis(dimethoxyphosphino)dimethylhydrazine (dmpdmh) with Ru-3(CO)(12): Evidence for facile ligand fragmentation in Ru-3(CO)(10)(dmpdmh) to give Ru-4(CO)(12)[mu-N(Me)N(Me)], Ru-3(CO)(11)[P(OMe)(3)], and Ru-3(CO)(9)[mu-P(OMe)(3)]

Thermolysis of the cluster Ru-3(CO)(12) with the bis(phosphanyl)hydrazine l igand (MeO)(2)PN (Me)N(Me)P(OMe)(2) (dmpdmh) in toluene at 75 degrees C fur nishes the known clusters Ru-4(CO)(12)[mu-N(Me)N(Me)] (2) and Ru-3(CO)(11)[ P(OMe)(3)] (3), in addition to the new cluster Ru-3 (CO)(10)(dmpdmh) (1) an d the phosphite-tethered cluster Ru-3(CO)(9)[mu-P(OMe)(3)] (4). The simple substitution product Ru-3(CO)(10)(dmpdmh), a logical intermediate to cluste rs 2-4, was synthesized by treating Ru-3(CO)(12) with Me3NO in CH2Cl2 at ro om temperature, and independent thermolysis reactions using cluster 1 was s hown to yield clusters 2-4, The solid-state structure of clusters 2 and 4 w ere unequivocally established by X-ray diffraction analysis. Ru-4(CO)(12)[m u-N(Me)N(Me)] crystallizes in the orthorhombic space group Pnna (#52), a = 12.913(1), b = 13.3238(6), c = 12.5690(8) Angstrom, V = 2162.5(2) Angstrom( 3), Z = 4, and d(calc) = 2.452 g/cm(3). Ru-3(CO)(9)[mu-P(OMe)(3)] crystalli zes in the triclinic space group <P(1)over bar>, a = 9.586(1), b = 14.354(1 ), c = 14.997(2) Angstrom, alpha = 89.82(1)degrees, beta = 98.36(1)degrees, gamma = 92.010(8)degrees, V = 2040.4(4) Angstrom(3), Z = 4, and d(calc) = 2.212 g/cm(3). The coordination of the dimethylazo linkage to the four ruth enium atoms in 2 and the phosphorus atom and one of the oxygen atoms of the methoxy groups to the three ruthenium centers in 4 are confirmed by X-ray analysis.