The Uranium(VI) Oxoazides [UO2 (N3 )2 ⋅CH3 CN], [(bipy)2 (UO2 )2 (N3 )4 ], [(bipy)UO2 (N3 )3 ]- , [UO2 (N3 )4 ]2- , and [(UO2 )2 (N3 )8 ]4

The reaction between [UO₂ F₂ ] and an excess of Me₃ SiN₃ in acetonitrile solution results in fluoride-azide exchange and the uranium(VI) dioxodiazide adduct [UO₂ (N₃ )₂ ⋅CH₃ CN] was isolated in quantitative yield. The subsequent reaction of [UO₂ (N₃ )₂ ⋅CH₃ CN] with 2,2'-bipyridine (bipy) resulted in the formation of the azido-bridged binuclear complex [(bipy)₂ (UO₂ )₂ (N₃ )₄ ]. The triazido anion [(bipy)UO₂ (N₃ )₃ ]^- was obtained by the reaction of [UO₂ (N₃ )₂ ⋅CH₃ CN] with stoichiometric amounts of bipy and the ionic azide [PPh₄ ][N₃ ]. The reaction of [UO₂ (N₃ )₂ ] with two equivalents of the [PPh₄ ][N₃ ] resulted in the formation of the mononuclear tetraazido anion [UO₂ (N₃ )₄ ]^2- as well as the azido-bridged binuclear anion [(UO₂ )₂ (N₃ )₈ ]^4- . The novel uranium oxoazides were characterized by their vibrational spectra and in the case of [(bipy)₂ (UO₂ )₂ (N₃ )₄ ]⋅CH₃ CN, [PPh₄ ][(bipy)UO₂ (N₃ )₃ ], [PPh₄ ]₂ [UO₂ (N₃ )₄ ], [PPh₄ ]₂ [UO₂ (N₃ )₄ ]⋅2CH₃ CN, and [PPh₄ ]₄ [(UO₂ )₂ (N₃ )₈ ]⋅4CH₃ CN by their X-ray crystal structures.

Preparation and Characterization of Antimony and Arsenic Tricyanide and Their 2,2'-Bipyridine Adducts

The arsenic(III) and antimony(III) cyanides M(CN)3 (M=As, Sb) have been prepared in quantitative yields from the corresponding trifluorides through fluoride-cyanide exchange with Me3 SiCN in acetonitrile. When the reaction was carried out in the presence of one equivalent of 2,2'-bipyridine, the adducts [M(CN)3 ⋅(2,2'-bipy)] were obtained. The crystal structures of As(CN)3 , [As(CN)3 ⋅(2,2'-bipy)] and [Sb(CN)3 ⋅(2,2'-bipy)] were determined and are surprisingly different. As(CN)3 possesses a polymeric three-dimensional structure, [As(CN)3 ⋅(2,2'-bipy)] exhibits a two-dimensional sheet structure, and [Sb(CN)3 ⋅(2,2'-bipy)] has a chain structure, and none of the structures resembles those found for the corresponding arsenic and antimony triazides.