Nickel-Ruthenium mixed-metal carbonyl clusters. Syntheses and solid state structures of the two tetrahedral clusters [PPh4][NiRu3(3-H)(CO)9(-CO)3] and [NEt4]2[NiRu3(CO)9(-CO)4].

Redox condensation of [Ru3H(CO)11]- with Ni(CO)4, in tetrahydrofuran solution, under a nitrogen atmosphere, yields the tetranuclear anion [NiRuH(CO)11)-. Subsequent deprotonation with Bu'OK in acetonitrile solution leads to the formation of the related dianion. Both anions have been characterized by spectroscopic techniques, elemental analysis and single crystal X-ray diffraction. [PPh4][NiRu3H(CO)12] crystallizes in the triclinic space group PI with unit cell dimensionsof a = 11.842(2) Å, b = 12.335(3) Å, c = 13.3080) Å, a = 91.89(2)°, β = 93.35(1)°,y = 96.41(2)°, Z = 2, V= 1926.9(7) Å'. The NiRu3, metal core of the molecule defines a distorted tetrahedron with nine terminal and three edge bridging carbonyl groups. The hydrido ligand was located by difference Fourier techniques and was found to bridge the NiRu2 basal triangle at a distance of 0.88(6) A from this plane. Selected average distances and angles are: Ru-Ru = 2.839 Å, Ru-Ni = 2.640 Å, Ru-C, = 1.910 A,Ru-Cb = 2.084 Å, Ni-Cb = 2.022 Å, Ru-H = 1.77 Å, C-0, = 1.135 Å, C-Ob = 1.159 Å, M-C-O, = 176.3°,M-C--Ob = 139.3°;other distances are: Ni-C1 = l.758(7) Å, Ni-H= 1.85(7) Å. [NEt4]2[NiRu3(CO)12] crystallizes in the orthorhombic space group Pnma (no. 62) with unit cell dimensions of a=20.247(5) Å, b = 15.038(4)Å, c = 12.079(3) Å, Z=4, V=3678(2) A'. The molecule contains a tetrahedral NiRu3 core with eight terminal and four edge bridging carbon monoxide groups which bridge the three Ni-Ru and one Ru-Ru bond. Average distances and angles are: Ru -Ru =2.3050A Ru-Ni 2.648 Å, Ru-Ct= 1.878 Å, Ru-Cb2.045 Å, Ni-Cb= 2.055 Å, C-Ot= 1.145 Å, C-01,=1.157 Å, M-C-O,= 176.9°, M-C-Ob = 138.6°; other distance is: Ni-Ct = 1.754(10) Å, t = terminal, b = bridging.