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A series of diboradiferrocenes with different aryl substituents was prepared through reaction of B,B-dichlorodiboradiferrocene 2 with arylcopper and Grignard reagents. The mesityl and pentafluorophenyl derivatives, 3–Mes and 3–Pf, were fully characterized by multinuclear NMR, MALDI-TOF mass spectrometry and X-ray crystallography, and their electronic structure was examined by UV-visible spectroscopy and cyclic voltammetry. A comparison of the data for 3–Mes and 3–Pf with those of the parent compound 3–Ph revealed the importance of electronic and steric effects of the substituents on the electronic structure of the compounds and ultimately the degree of electronic interaction between the two ferrocene moieties. An unusually large redox splitting of ΔE = 703 mV was determined from the cyclic voltammogram of 3–Pf. [ABSTRACT FROM AUTHOR]

Recent advances in the chemistry of pentafluorophenyl copper are discussed, including the observation of strongly luminescent adducts with pyridine, the first successful structural characterization of an organocopper–arene complex, and the complexation with electron-rich transition metal complexes such as ferrocene derivatives. In addition, new applications in synthetic organometallic chemistry are discussed, which include the discovery of tin/copper exchange reactions for the preparation of organocopper compounds that are otherwise not readily accessible, and the selective transfer of the C6F5 groups to boron to form catalytically active and electronically interesting organoboron polymers. [ABSTRACT FROM AUTHOR]

The Lewis acidity of boron in diboradiferrocene 1 is strongly enhanced through oxidation of the iron atoms as evident from examination of X-ray structural parameters of the mixed-valent cation 1+PF6 and further confirmed from the strong complexation of MeCN to the dication in 22+(I3)2. [ABSTRACT FROM AUTHOR]