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.

Abstract

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.