Oxidation of Tris(N,N-disubstituted-dithiocarbamato) Complexes of Ruthenium(III). X-Ray Structure Determination of Bis(N,N-diethyldithiocarbamato)-μ-tris(N,N-diethyldithiocarbamato)-diruthenium(III) Tetrafluoroborate, [RU₂(Et₂dtc)5]Bf₄

The products of the oxidation reaction of tris(N,N-disubstituted-dithiocarbamato)ruthenium(III), Ru(R₂dtc)₃, with BF₃ gas open to the air have been characterized by standard analytical and spectroscopic means. The novel metal-containing product has the formula [Ru₂(R₂dtc)₅]BF₄ and the crystal structure has been determined for R = ethyl by three-dimensional single-crystal x-ray analysis. The space group is Pna2₁ with lattice constants a = 18.303 (6) Å, b = 20.713 (9) Å, and c = 12.416 (5) Å. The structure was solved by conventional heavy-atom techniques and refined by least-squares methods to weighted and unweighted R factors of 0.089 and 0.095, respectively, for 2100 independent reflections. The density of 1.54 g/cm³ computed from the unit cell volume of 4707 ų on the basis of four [Ru₂(Et₂dtc)₅]BF₄·C ₃H₆O molecules per unit cell agrees well with the 1.55 g/cm³ determined by flotation methods. The structure of the cation consists of a triply bridged diruthenium compound (see Figures 1-3) with a Ru-Ru distance of 2.743 (3) Å. This distance and the diamagnetism of the compound are consistent with a bond order equal to ∼1. The structure is novel because it is the first example where dithiocarbamate ligands connect two metals in both bridging fashions simultaneously. The mechanism of the oxidation reaction is discussed and compared to the analogous reaction of Fe(R₂dtc)₃ which gives a monomeric tris-chelate complex of iron(IV). A thorough electrochemical study has also been carried out on Ru(R₂dtc)₃ and [Ru₂(R₂dtc)₅]BF₄ complexes.