Reactions of Mesityl Azide with Ferrocene‐Based N‐Heterocyclic Germylenes, Stannylenes and Plumbylenes, Including PPh₂‐Functionalised Congeners

Abstract

The reactivity of ferrocene-based N-heterocyclic tetrylenes [{Fe(η 5 À C 5 H 4 À NSitBuMe 2 ) 2 }E] (E = Ge, Sn, Pb) towards mesityl azide (MesN 3 ) is compared with that of PPh 2functionalised 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 À C 5 H 4 À 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.

Reactions of main group compounds with azides forming organic nitrogen-containing species

“…In 2022, Siemeling et al reported the reactions of ferrocene-based N-heterocyclic plumbylene with azides (Scheme 110). 153 The plumbylene Pb3 did not react with MesN 3 even heating the toluene solution at 105 °C. In contrast to Pb3 , the PPh 2 -functionalised congener Pb4 smoothly reacted with MesN 3 at 60 °C to generate the additional product Pb4-P in 52% yield.…”

“…In 2022, Siemeling et al developed the ferrocene-based N-heterocyclic germylenes and investigated their reactivity towards azides (Scheme 89). 153 Treatment of Ge14a with MesN 3 in hexane led to the formation of germanimine Ge14a-P in 72% yield. Ge14b with a PPh 2 functionality reacted with MesN 3 affording the germanimine Ge14b-P1 in 72% yield.…”

“…In 2022, Siemeling et al described the reactivity of the ferrocene-based N-heterocyclic tetryenes towards azides (Scheme 105). 153 Treatment of Sn11 with two equivalents of MesN 3 led to the formation of stannatetrazol Sn11-P in 83% yield. Sn11-P is formed via the [2+3] cycloaddition between stannanimine intermediate and the second azide molecule.…”

A germanimidoyl chloride: synthesis, characterization and reactivity

“…The Ge–N bond distance is 1.647(4) Å, which is the shortest among the reported GeN double bonds (1.67–1.72 Å). 17–25 It is even shorter than that in the carbene stabilized cationic germanimine (1.669(4) Å) reported by Aldridge and coworkers. 20 The distances of Ge1–Cl1 (2.2043(12) Å) and Ge1–C1 (1.931(4) Å) are both slightly shorter than those found in the precursor M s Fluind t Bu -GeCl (Ge–Cl: 2.2500(6) Å; Ge–C: 2.007(2) Å).…”

“…16 Since then, several stable germanimines have been obtained by employing sterically congested ligands to thermodynamically and kinetically stabilize the reactive GeQN double bonds. [17][18][19][20][21][22][23][24][25] Strikingly, Ando et al synthesized bisgermanimines II through the reactions of bis[bis(trimethylsilyl)methyl]germylene with diazidosilanes. 18 The Fulton group obtained a series of germanimines, which were synthesized by the reactions of diaminogermylenes and organic azides.…”