The Molybdenum(V) and Tungsten(VI) Oxoazides [MoO(N3)3], [MoO(N3)3⋅2 CH3CN], [(bipy)MoO(N3)3], [MoO(N3)5]2−, [WO(N3)4], and [WO(N3)4⋅CH3CN]. Issue 51 (2nd November 2015) - Haiges, Ralf
Abstract: A series of novel molybdenum(V) and tungsten(VI) oxoazides was prepared starting from [MOF4 ] (M=Mo, W) and Me3 SiN3 . While [WO(N3 )4 ] was formed through fluoride–azide exchange in the reaction of Me3 SiN3 with WOF4 in SO2 solution, the reaction with MoOF4 resulted in a reduction of Mo VI to Mo V and formation of [MoO(N3 )3 ]. Carried out in acetonitrile solution, these reactions resulted in the isolation of the corresponding adducts [MoO(N3 )3 ⋅2 CH3 CN] and [WO(N3 )4 ⋅CH3 CN]. Subsequent reactions of [MoO(N3 )3 ] with 2, 2′‐bipyridine and [PPh4 ][N3 ] resulted in the formation and isolation of [(bipy)MoO(N3 )3 ] and [PPh4 ]2 [MoO(N3 )5 ], respectively. Most molybdenum(V) and tungsten(VI) oxoazides were fully characterized by their vibrational spectra, impact, friction and thermal sensitivity data and, in the case of [WO(N3 )4 ⋅CH3 CN], [(bipy)MoO(N3 )3 ], and [PPh4 ]2 [MoO(N3 )5 ], by their X‐ray crystal structures. Abstract : Mo and W make an impact : A series of novel molybdenum(V) and tungsten(VI) oxoazides were obtained and characterized. [MoO(N3 )3 ] and [WO(N3 )4 ] were obtained by fluoride–azide exchange from [MOF4 ] and Me3 SiN3 as very friction‐ and impact‐sensitive solids. With CH3 CN, [MoO(N3 )3 ] and [WO(N3 )4 ] form stable acetonitrile adducts. The reactions of [MoO(N3 )3 ] with 2, 2′‐bipyridine and N3 − afforded [(bipy)MoO(N3 )3 ] and [MoO(N3 )5 ] 2−, respectively.