Ruthenacarboranes Based on 5-Phenyl- and 5,6-Diphenyl Dicarbollide Ligands. Synthesis and Transformations

Reactions of cesium salts of substituted nido-carborane anions [nido-5-Ph-7,8-C₂B₉H₁₁]^- (1) and [nido-5,6-Ph₂-7,8-C₂B₉H₁₀]^- (2) bearing bulky phenyl groups at boron atoms in the lower bent of carborane ligand with RuCl₂(PPh₃)dppb (3) in benzene solution led to the novel 18-e closo-ruthenacarboranes 3,3-(Ph₂P(CH₂)₄PPh₂)-3-H-3-Cl-9-Ph-12-X-closo-3,1,2-RuC₂B₉H₉ (X = H (4), Ph (5)). Reactions of the obtained complexes with carbon tetrachloride allowed to obtain corresponding 17-e Ru(III) complexes 3,3-(Ph₂P(CH₂)₄PPh₂)-3-Cl-9-Ph-12-X-closo-3,1,2-RuC₂B₉H₁₀ (X = H (7), Ph (8)). The reaction of 4 with isopropylamine in acetonitrile leads to the formation of the corresponding acetonitrile complex 3,3-(Ph₂P(CH₂)₄PPh₂)-3-CH₃CN-9-Ph-12-closo-3,1,2-RuC₂B₉H₁₀ (10). The novel ruthenacarborane clusters 5 and 8 were characterized by single crystal X-ray diffraction which unambiguously confirmed the proposed structures. The cyclic voltammetry studies of compounds 4 and 5 showed its ability to reversible reduction to the corresponding Ru(II) species.