The electrochemical oxidation of 1,1′-bis(diphenylphosphino)ferrocene (dppf) at a platinum electrode in 1,2-dichloroethane has been studied by cyclic voltammetry, controlled potential electrolysis, and ³¹P NMR spectroscopy. The compound undergoes a ferrocene-based reversible oxidation, which is followed by a fast chemical reaction, involving the phosphorus substituent on the cyclopentadienyl rings, to give dppfO, dppfO₂, dppfH⁺ and dppfH₂²⁺. Kinetic data suggest that the reaction involes a reversible intramolecular electron transfer between the ferrocene core and the electron-rich substituents to give a phosphinium radical ion, which undergoes a second order rate-determining dimerization or a reaction with the parent compound to give a ferrocenylphosphine dimer cation radical, the ultimate fate of which is the formation of protonated and oxygenated dppf derivatives by nucleophilic attack by water present in the reaction medium. Evidence for the formation of the transient monomeric phosphinium radical was obtained by trapping it with 1,1′-diphenylethylene to give phosphorus-bonded monoalkene adducts of dppf.

中文翻译：

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1,1'-双（二苯基膦基）二茂铁（dppf）的杂多金属配合物：VII。dppf的氧化还原行为

通过循环伏安法，控制电位电解和³¹ P NMR光谱研究了1,1'-双（二苯基膦基）二茂铁（dppf）在1,2-二氯乙烷中的铂电极上的电化学氧化。该化合物进行二茂铁基可逆氧化，然后进行快速化学反应，该化学反应涉及环戊二烯基环上的磷取代基，得到dppfO，dppfO ₂，dppfH ⁺和dppfH ₂ ²⁺。动力学数据表明，该反应涉及二茂铁核与富电子取代基之间的可逆分子内电子转移，从而产生phosph基自由基离子，该基团经历了二级速率决定的二聚作用或与母体化合物的反应产生了二茂铁基膦二聚体阳离子自由基，其最终结局是反应介质中存在的水通过亲核攻击而形成质子化和氧化的dppf衍生物。通过用1，1'-二苯乙烯捕获，形成dppf的磷键合单烯烃加成物，得到了形成瞬态单体phosph基的证据。