A series of new P^P-chelating ligands constituted by a dicationic -[P(H2Im)2]+2 unit (H2Im = 1,3-dimethyl-4,5-dihydroimidazol-2-ylidene) and a -PPh2 group connected through structurally different backbones have been synthesized. Evaluation of their reactivity toward different metal centers provides evidence that the dicationic fragment, otherwise reluctant to coordinate metals, readily participates in the formation of chelates when embedded into such a scaffold. Moreover, it significantly enhances the Lewis acidity of the metals to which it coordinates. This property has been used to develop a Rh catalyst that efficiently triggers the hydroarylation of dienes with electron-rich aromatic molecules. Kinetic studies and deuterium-labeling experiments, as well as density functional theory calculations, were performed in order to rationalize these findings.

中文翻译：

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α-双阳离子螯合膦：合成及在二烯氢化芳基化中的应用

由双阳离子-[P(H2Im)2]+2 单元（H2Im = 1,3-二甲基-4,5-二氢咪唑-2-亚基）和连接的-PPh2 基团构成的一系列新的P^P-螯合配体通过结构不同的主链已经被合成。评估它们对不同金属中心的反应性提供了证据，表明双阳离子片段，否则不愿意配位金属，当嵌入这种支架时很容易参与螯合物的形成。此外，它显着增强了与其配位的金属的路易斯酸度。这一特性已被用于开发一种 Rh 催化剂，该催化剂可有效触发二烯与富电子芳香分子的加氢芳基化反应。动力学研究和氘标记实验，以及密度泛函理论计算，