Reactions of Mesityl Azide with Ferrocene-Based N-Heterocyclic Germylenes, Stannylenes and Plumbylenes, Including PPh 2 -Functionalised Congeners.

The reactivity of ferrocene-based N-heterocyclic tetrylenes [{Fe(η 5 -C 5 H 4 -NSitBuMe 2 ) 2 }E] (E=Ge, Sn, Pb) towards mesityl azide (MesN 3 ) is compared with that of PPh 2 -functionalised congeners exhibiting two possible reaction sites, namely the E II and P III atom. For E=Ge and Sn the reaction occurs at the E II atom, leading to the formation of N 2 and an E IV =NMes unit. The germanimines are sufficiently stable for isolation. The stannanimines furnish follow-up products, either by [2+3] cycloaddition with MesN 3 or, in the PPh 2 -substituted case, by NMes transfer from the Sn IV to the P III atom. Whereas [{Fe(η 5 -C 5 H 4 -NSitBuMe 2 ) 2 }Pb] and other diaminoplumbylenes studied are inert even under forcing conditions, the PPh 2 -substituted congener forms an addition product with MesN 3 , thus showing a behaviour similar to that of frustrated Lewis pairs. The germylenes of this study afford copper(I) complexes with CuCl, including the first structurally characterised linear dicoordinate halogenido complex [CuX(L)] with a heavier tetrylene ligand L.