Synthesis, characterization and chemistry of bis-(pentafluorophenyl)boryl ferrocene

Carpenter, Bryon E.; Piers, Warren E.; Parvez, Masood; Yap, Glenn P. A.; Rettig, Steven J.

doi:10.1139/cjc-79-5-6-857

Cited by 9 publications

(21 citation statements)

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“…[17] Attractive is also that the Lewis acidity of the borane moiety can be tuned through reversible redox chemistry at the metal centers. [18,19] Prior efforts by our group involved studies on the binding properties of heteronuclear bidentate 1-stannyl-2-borylferrocene derivatives, which are obtained in their racemic form by a rearrangement reaction from 1,1'-bis(trimethylstannyl) ferrocene and boron halides RBCl 2 (R = Cl, Ph, C 6 F 5 ). [13,14] We have demonstrated that the bidentate Lewis acid 1,2-Fc-Abstract: Enantiomerically pure metalated 2-(1-naphthyl)ferrocene (NpFc) derivatives NpFcM (M = SnMe 3 , HgCl) were prepared and characterized by multinuclear NMR and UV/Vis spectroscopy, cyclic voltammetry, and elemental analysis.…”

Section: Introductionmentioning

confidence: 99%

Planar Chiral Organoborane Lewis Acids Derived from Naphthylferrocene

Chen

Venkatasubbaiah

Thilagar

et al. 2010

Chemistry A European J

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Enantiomerically pure metalated 2-(1-naphthyl)ferrocene (NpFc) derivatives NpFcM (M=SnMe(3), HgCl) were prepared and characterized by multinuclear NMR and UV/Vis spectroscopy, cyclic voltammetry, and elemental analysis. Optical rotation measurements were performed and the absolute configuration of the new planar chiral ferrocene species was confirmed by single-crystal X-ray diffraction analysis. The mercuriated species NpFcHgCl proved suitable as a reagent for the preparation of the chiral organoborane Lewis acid NpFcBCl(2), which can in turn be converted to other ferrocenylboranes by replacement of Cl with nucleophiles. The highly Lewis acidic perfluoroarylborane derivatives NpFcB(C(6)F(5))Cl and NpFcB(C(6)F(5))(2) were successfully prepared by treatment with CuC(6)F(5). The structures were studied by single-crystal X-ray diffraction and variable-temperature (19)F NMR spectroscopy, which suggested that pi stacking of a C(6)F(5) group on boron with the adjacent naphthyl group is energetically favorable. UV/Vis absorption spectroscopy and cyclic voltammetry measurements were performed to examine the electronic properties of these novel redox-active chiral Lewis acids.

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Section: Introductionmentioning

confidence: 99%

Planar Chiral Organoborane Lewis Acids Derived from Naphthylferrocene

Chen

Venkatasubbaiah

Thilagar

et al. 2010

Chemistry A European J

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“…This difference is because the transformation of a neutral borole to a cationic borole greatly enhances the electron deficiency and Lewis acidity of the boron center, and leads to undesired coordination and/or decomposition of the resulting cationic molecule. [15] Most revealingly, two well-separated reduction waves for 1 were identified in THF solution. As shown in Figure 1, 1 displays a quasi-reversible reduction event centered at E 0 1/2 = À1.96 V indicating the formation of stable borole radical anion, [1]C À .…”

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confidence: 95%

The Reduction Chemistry of Ferrocenylborole

et al. 2010

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Time to B radical: One‐electron reduction of 1‐ferrocenyl‐2,3,4,5‐tetraphenylborole results in a radical anion with 5 π electrons in the borole ring. Both EPR spectroscopic investigations and spin density calculations confirm the formation of a borol radical (see picture). Further reduction stimulates an intramolecular [(C5H5)Fe] migration from the cyclopentadienyl anion to the borole dianion.

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“…The Ohfip-ligand was proven to provide suitable Lewis acidity to an electron-deficient central atom, e.g., in the related B(Ohfip) 3 , as well as in monomeric Al[OC(CF 3 ) 3 ] 3 or dimeric Al 2 (Ohfip) 6 [30][31][32][33][34]. Carpenter and coworkers suggested that oxidation enhances the Lewis acidity of ferrocenylboranes, so that the B center in certain borylferrocinium compounds abstracts a fluoride from a [BF 4 ] -counteranion [35]. To avoid this side reaction, we decided to use the silver salt of the perfluorinated alkoxyaluminate anion [Al(OR F ) 4 ] -(R F = C(CF 3 ) 3 ) as an oxidant.…”

Section: Introductionmentioning

confidence: 99%