Azido- or hydroxyl-capped half-cubanes containing Cp*Rh fragments: [Cp*3Rh3(μ-X)3(μ3-X)]2+ (X− = OH− or N3−)

Abstract

Treatment of [Cp*Rh(H₂O)₃](OTf)₂ (1) with Me₃SiNH-t-Bu in acetone gave a hydroxyl-capped half-cubane [Cp*₃Rh₃(μ-OH)₃(μ₃-OH)](OTf)₃(t-BuNH₃) (2). Slow diffusion of Me₃SiN₃ in diethyl ether into compound 1 in acetone produced an azido-capped half-cubane [Cp*₃Rh₃(μ-N₃)₃(μ₃-N₃)](OTf)₂ (3). On the other hand, treating 1 with Me₃SiN₃ in acetone gave an azido-bridged, dinuclear rhodium(III) complex [Cp*Rh(μ-N₃)(OH₂)]₂(OTf)₂ (4). Complexes 2 and 3 represent the first azido- or hydroxyl-capped, incomplete cubane-type Rh clusters. Under appropriate conditions, complexes 2 and 3 could be converted to complex 4. The structures of all products were determined by X-ray diffraction.