Rhodacarboranes containing σ- and π-carboranyl ligands in one molecule

The first rhodacarboranes containing σ- and π-carboranyl ligands in one molecule were synthesized. At the first step rhodium(I) complexes 3-(η2:η2-1,5-COD)-4-X-3,1,2-RhC2B9H10 (X = NMe3, NMe2CH2Ph, Py) were synthesized by... [ view full abstract ]

The first rhodacarboranes containing σ- and π-carboranyl ligands in one molecule were synthesized. At the first step rhodium(I) complexes 3-(η²:η²-1,5-COD)-4-X-3,1,2-RhC₂B₉H₁₀ (X = NMe₃, NMe₂CH₂Ph, Py) were synthesized by the reactions of dimeric complex [(1,5-COD)RhCl]₂ with sodium or lithium derivatives of the corresponding charge-compensated dicarbollides (Scheme 1). Contrary to another two, the NMe₃-derivative was unstable and was passed to the next step without purification. Structure of the NMe₂CH₂Ph derivative was confirmed by single crystal X-ray diffraction.

At the second step, the treatment of the cyclooctadiene rhodium(I) complexes with hydrogen chloride produces the corresponding chloride-bridged dimeric rhodium(III) complexes [μ-3-Cl-3-Cl-4-X-3,1,2-RhC₂B₉H₁₀]₂ (X = NMe₃, NMe₂CH₂Ph, Py) (Scheme 2).

At the third step, the reaction of [μ-3-Cl-3-Cl-4-X-3,1,2-RhC₂B₉H₁₀]₂ (X = NMe₃, Py) with disodium ortho-carboranyl-1,2-dithiolate 1,2-(NaS)₂-1,2-C₂B₁₀H₁₀ gave deep green complexes 3-(κ(S,S)-1’,2’-C₂B₁₀H₁₀-1’,2’-S₂)-4-X-3,1,2-RhC₂B₉H₁₀ (Scheme 3). Structure of 3-(κ(S,S)-1’,2’-C₂B₁₀H₁₀-1’,2’-S₂)-4-Me₃N-3,1,2-RhC₂B₉H₁₀ was determined by single crystal X-ray diffraction (Figure 1).

Acknowledgement. This work was supported by Russian Foundation for Basic Research (16-53-53079 and 16-03-00724).