Quantifying the Donor Strength of Ligand-Stabilized Main Group Fragments.
Quantifying the Donor Strength of Ligand-Stabilized Main Group Fragments.
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DOI：
10.1021/jacs.9b02598
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发表时间：
2019-04
影响因子：
15
通讯作者：
Leon Maser;C. Schneider;Lisa Vondung;Lukas Alig;R. Langer
中科院分区：
文献类型：
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作者：
Leon Maser;C. Schneider;Lisa Vondung;Lukas Alig;R. Langer
不寻常的结合性能，使难以捉摸的物种的稳定，和有益的性能均相催化剂已被预测和证明的配体稳定的主要基团片段，如正膦和-卡宾。然而，通过实验手段对其结合特性进行量化和比较仍然是主要挑战。在本文中，我们描述了一系列[（PEP）IrCl（CO）（H）] q类型的铱（III）钳形配合物，可以量化中心给体基团E（q = 0，+1，+2）的给体强度。我们的研究表明，膦稳定的硼（I）和碳（0）化合物是非常强的中性供体基团相比，常见的旁观者配体在均相催化，如卡宾和膦。我们的实验和计算结果第一次允许和证明了阳离子，中性和阴离子配体的供体强度的比较。在量子化学研究的基础上，我们进一步证明了膦稳定的硼烯和碳（0）化合物的重同系物表现出轻微降低的供体性质。
Unusual binding properties, enabling the stabilization of elusive species, and beneficial properties for homogeneous catalysts have been predicted and demonstrated for ligand-stabilized main group fragments, such as carbodiphosphoranes and -carbenes. However, the quantification and comparison of their binding properties by experimental means still represent major challenges. In this article, we describe a series of iridium(III) pincer complexes of the type [(PEP)IrCl(CO)(H)] q enabling the quantification of the donor strength of the central donor group E ( q = 0, +1, +2). Our investigations show that phosphine-stabilized boron(I) and carbon(0) compounds are exceptionally strong neutral donor groups in comparison to common spectator ligands in homogeneous catalysis such as carbenes and phosphines. Our experimental and computational results for the first time allow and justify the comparison of the donor strength of cationic, neutral, and anionic ligands. On the basis of quantum chemical investigations, we further demonstrate that the heavier homologues of phosphine-stabilized borylenes and carbon(0) compounds exhibit slightly diminished donor properties.