Tetrazastannoles versus distannadiazanes – a question of the tin(ii) source

Abstract

Various tin(II) compounds such as Mes*₂Sn (Mes* = 2,4,6-tri-tert-butylphenyl), Sn[N(SiMe₃)₂]₂ and TerSnCl (Ter = 2,6-bis(2,4,6-trimethylphenyl)phenyl) could be readily oxidised by organic azides to release N₂, forming nitrogen-tin compounds. Depending on the used Sn(II) compound, the reactions with two equivalents of azide led to the formation of tetrazastannoles (R₂N₄SnR′₂) or cyclo-distannadiazanes [R₂Sn(μ-NR′)]₂. The reactivity was independent of the electronic situation of the organic azide. Additionally, Mes*₂Sn formed an amido-azido compound of the type R(R′)Sn(N(SiMe₃)₂)N₃ in the presence of Me₃SiN₃. Presumably, the corresponding tetrazastannole was formed in the first step followed by a ring opening reaction. The same holds true for the reaction of Sn[N(SiMe₃)₂]₂ with Me₃SiN₃ while TerSnCl showed no reaction in the presence of Me₃SiN₃, even after prolonged heating.