Zinc-Mediated Transmetalation as a Route to Anionic N‑Heterocyclic Olefin Complexes in the p‑Block

Anionic N-heterocyclic olefins (aNHOs) are suited well for the stabilization of low-coordinate inorganic complexes, due to their steric tunability and strong σ- and π-electron donating abilities. In this study, the new two-coordinate zinc complex (MeIPrCH)2Zn (MeIPrCH = [(MeCNDipp)2CCH]−, Dipp = 2,6-diisopropylphenyl) is shown to participate in a broad range of metathesis reactions with main group element-based halides and hydrides. In the case of the group 14 halides, Cl2E·dioxane (E = Ge and Sn), transmetalation occurs to form dinuclear propellane-shaped cations, [(MeIPrCHE)2(μ-Cl)]+, while the aNHO-capped phosphine ligand MeIPrCH-PPh2 is obtained when (MeIPrCH)2Zn is combined with ClPPh2. Lastly, ZnH2 elimination drives transmetalation between (MeIPrCH)2Zn and hydroboranes and hydroalumanes, leading to Lewis acidic aNHO-supported -boryl and -alane products.

阴离子型氮杂环烯烃（Anionic N-heterocyclic olefins, aNHOs）凭借其空间位阻可调性以及优异的σ、π电子给体能力，可高效用于低配位无机配合物的稳定化。本研究中，新型双配位锌配合物(MeIPrCH)₂Zn [其中MeIPrCH = [(MeCNDipp)₂C=CH]⁻，Dipp = 2,6-二异丙基苯基（2,6-diisopropylphenyl）]可与多种主族元素卤化物及氢化物发生一系列复分解反应。针对第14族卤化物Cl₂E·二氧六环加合物（E=锗Ge、锡Sn），体系会发生转金属化反应，生成双核螺桨烷型阳离子[(MeIPrCHE)₂(μ-Cl)]⁺；而当(MeIPrCH)₂Zn与ClPPh₂反应时，可得到aNHO封端的膦配体MeIPrCH-PPh₂。最后，脱去ZnH₂的过程可驱动(MeIPrCH)₂Zn与硼烷类、铝烷类化合物之间的转金属化反应，最终得到路易斯酸性的aNHO稳定的硼基及铝基产物。