Wang Yi, McGrady John E, Sun Zhong-Ming
Tianjin Key Lab of Rare Earth Materials and Applications, State Key Laboratory of Elemento-Organic Chemistry, School of Materials Science and Engineering, Nankai University, Tianjin 300350, China.
Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K.
Acc Chem Res. 2021 Mar 16;54(6):1506-1516. doi: 10.1021/acs.accounts.0c00876. Epub 2021 Mar 8.
ConspectusGroup 14 Zintl anions [E] (E = Si-Pb, = 4, 5, 9, 10) are synthetically accessible, and their diverse chemical reactivity makes them valuable synthons in the construction of larger nanoclusters with remarkable structures, intriguing patterns of chemical bonding, and tunable physical and chemical properties. A plethora of novel cluster anions have now been isolated from the reactions of polyanionic [E] precursors with low-valent d-/f-block metal complexes, main-group organometallics, or organics in polar aprotic solvents. The range of products includes intermetalloid clusters with transition metal atom(s) embedded in main-group element cages, organometallic Zintl anions in which [E] acts as a ligand, intermetallic Zintl anions where [E] is bridged by ligand-free transition metal atom(s), organo-Zintl anions where [E] is functionalized with organic-group(s), and oligomers formed through oxidative coupling reactions. The synthesis and characterization of these unconventional complexes, where important contributions to stability come from ionic, covalent, and metal-metal bonds as well as weaker aurophilic and van der Waals interactions, extend the boundaries of coordination chemistry and solid-state chemistry. Substantial progress has been made in this field over the past two decades, but there are still many mysteries to unravel related to the cluster growth mechanism and the controllable synthesis of targeted clusters, along with the remarkable and diverse patterns of chemical bonding that present a substantial challenge to theory. In this Account, we hope to shed some light on the relationship between structure, electronic properties, and cluster growth by highlighting selected examples from our recent work on homoatomic deltahedral [E] anions, including (1) germanium-based Zintl clusters, such as the supertetrahedral intermetallic clusters [MGe] (M = Zn, Cd) and the sandwich cluster {(Ge)[η-Ge(PdPPh)]} with a heterometallic Ge@Pd interlayer; (2) tin-based intermetalloid clusters [M@Sn] and the application of [Co@Sn9] in bottom-up synthesis; and (3) lead clusters with precious metal cores, including the largest Zintl anion [AuPb]. In addition to their intrinsic appeal from a structural and electronic perspective, these new cluster anions also show promise as precursors for the development of new materials with applications in heterogeneous catalysis, where we have recently reported the selective reduction of CO.
综述
第14族津特耳阴离子[E]（E = Si - Pb， = 4, 5, 9, 10）可通过合成得到，其多样的化学反应活性使其成为构建具有非凡结构、有趣化学键模式以及可调物理和化学性质的更大纳米团簇的有价值的合成子。现在，通过多阴离子[E]前体与低价d - / f族金属配合物、主族有机金属化合物或有机化合物在极性非质子溶剂中的反应，已分离出大量新型团簇阴离子。产物范围包括在主族元素笼中嵌入过渡金属原子的类金属间簇、[E]作为配体的有机金属津特耳阴离子、[E]由无配体过渡金属原子桥连的金属间津特耳阴离子、[E]被有机基团官能化的有机 - 津特耳阴离子以及通过氧化偶联反应形成的低聚物。这些非常规配合物的合成与表征，其中稳定性的重要贡献来自离子键、共价键和金属 - 金属键以及较弱的亲金作用和范德华相互作用，扩展了配位化学和固态化学的边界。在过去二十年中，该领域取得了重大进展，但仍有许多谜团有待解开，涉及团簇生长机制、目标团簇的可控合成以及对理论构成重大挑战的显著且多样的化学键模式。在本综述中，我们希望通过突出我们最近关于同原子三角面体[E]阴离子的工作中的选定示例，来阐明结构、电子性质与团簇生长之间的关系，包括（1）基于锗的津特耳簇，如超四面体金属间簇[MGe]（M = Zn，Cd）以及具有异金属Ge@Pd夹层的夹心簇{(Ge)[η - Ge(PdPPh)]}；（2）基于锡的类金属间簇[M@Sn]以及[Co@Sn9]在自下而上合成中的应用；（3）具有贵金属核的铅簇，包括最大的津特耳阴离子[AuPb]。除了从结构和电子角度来看具有内在吸引力外，这些新的团簇阴离子还显示出有望作为开发用于多相催化应用的新材料的前体，我们最近在其中报道了CO的选择性还原。
