Recent studies in transition metal catalysis employing chelating phosphines have suggested a role for partial ligand oxidation in formation of the catalytically active species, with potentially widespread relevance in a number of catalytic systems. We examine the internal redox reaction of Pd^II(bisphosphine)X₂ (X = Cl, OAc, etc.) complexes to reveal previously underexplored aspects of bisphosphine monoxides (BPMOs), including evaluation of ligand structure and development of general reaction conditions to access a collection of structurally diverse BPMO precatalysts based on organopalladium oxidative addition complexes. In particular, a series of Pd^II(BPMO)(R)(X) (R = aryl, alkyl; X = I, Br) oxidative addition complexes bearing 24 different BPMO ligands were characterized by NMR and X-ray crystallography. Comparison of the catalytic performance of the oxidative addition complexes of bisphosphine versus bisphosphine monoxides as precatalysts is demonstrated to be an enabling diagnostic tool in Pd catalytic reaction development. Finally, the differences in catalytic behavior between bisphosphine and bisphosphine monoxide complexes were rationalized through solid-state parametrization and stoichiometric experiments.

中文翻译：

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钯双膦一氧化氢复合物：合成、范围、机制和催化相关性


最近使用螯合膦的过渡金属催化研究表明，部分配体氧化在催化活性物质的形成中的作用，在许多催化系统中具有潜在的广泛相关性。我们研究了 Pd^II（双膦）X₂（X = Cl、OAc 等）配合物的内部氧化还原反应，以揭示以前未充分探索的双膦一氧化氢 （BPMO） 的各个方面，包括配体结构的评估和一般反应条件的开发，以获得基于有机钯氧化加成配合物的结构多样化的 BPMO 预催化剂的集合。特别是一系列 Pd^II（BPMO）（R）（X）（R = 芳基，烷基;通过 NMR 和 X 射线晶体学表征了带有 24 种不同 BPMO 配体的 X = I， Br） 氧化加成复合物。双膦与一氧化二膦作为预催化剂的氧化加成复合物的催化性能的比较被证明是 Pd 催化反应开发中的一种有利诊断工具。最后，通过固态参数化和化学计量实验，合理化了双膦和双膦一氧化氢复合物之间催化行为的差异。