Structural studies in the ruthenium–dithiocarbamate system. Part II. Crystal structures of two salts of the [Ru2(dtc)5]+ cation, one containing the [Ru2Cl6]2– anion

Abstract

The crystal structures of two derivatives of ruthenium di-isopropyldithiocarbamate (dtc) have been determined by X-ray diffraction: viz. (I)[Ru₂(dtc)₅]Cl,2.5C₆H₆ and (II)[Ru₂(dtc)₅]₂[Ru₂Cl₆],2CHCl₃,(C₆H₁₂ ?). The structures were solved by the heavy-atom method and refined by least squares to R 0·084 [(I) 5 079 reflections] and 0.12 [(II) 4 714 reflections]. Crystals of both are monoclinic, space groups P2_l/a(I), P2₁n(II); for (I)a= 27.13(1), b= 17.25(2), c= 14.53(3)Å, β= 97.82(4)°, Z= 4; for (II)a= 33.83(1), b= 12.527(2), c= 15.825(2)Å, β= 95.72(2)°, Z= 2. Within the [Ru₂(dtc)₅]⁺ cation, a strong Ru ⋯ Ru interaction is found, the geometry of the bridging ligands being greatly compressed with a short Ru ⋯ Ru distance [2·789(4)Å]. The bridging dithiocarbamate groups are also unusual: the p_π orbital of one of the sulphur atoms is utilized for bonding so that there is an unusual disparity in the two C ⋯ S distances, the longer of which approximates to the single-bond value. (II) contains the novel [Ru₂Cl₆]^2– centrosymmetric anion; the ruthenium atoms are pseudo-tetrahedral.