0000000001298934
AUTHOR
Adrian Y. Houghton
Direct observation of a borane-silane complex involved in frustrated Lewis-pair-mediated hydrosilylations.
Perfluorarylborane Lewis acids catalyse the addition of silicon-hydrogen bonds across C=C, C=N and C=O double bonds. This 'metal-free' hydrosilylation has been proposed to occur via borane activation of the silane Si-H bond, rather than through classical Lewis acid/base adducts with the substrate. However, the key borane/silane adduct had not been observed experimentally. Here it is shown that the strongly Lewis acidic, antiaromatic 1,2,3-tris(pentafluorophenyl)-4,5,6,7-tetrafluoro-1-boraindene forms an observable, isolable adduct with triethylsilane. The equilibrium for adduct formation was studied quantitatively through variable-temperature NMR spectroscopic investigations. The interactio…
Mechanistic Studies on the Metal-Free Activation of Dihydrogen by Antiaromatic Pentarylboroles
The perfluoro- and perprotiopentaphenylboroles 1 and 2 react with dihydrogen to effect H-H bond cleavage and formation of boracyclopentene products. The mechanism of this reaction has been studied experimentally through evaluation of the kinetic properties of the slower reaction between 2 and H(2). The reaction is first-order in both [borole] and [H(2)] with activation parameters of ΔH(‡) = 34(8) kJ/mol and ΔS(‡) = -146(25) J mol(-1) K(-1). A minimal kinetic isotope effect of 1.10(5) was observed, suggesting an asynchronous geometry for H-H cleavage in the rate-limiting transition state. To explain the stereochemistry of the observed products, a ring-opening/ring-closing mechanism is propos…
Hydrogen activation with perfluorinated organoboranes: 1,2,3- tris(pentafluorophenyl)-4,5,6,7-tetrafluoro-1-boraindene
The perfluorinated boraindene 3 was synthesized and fully characterized. Both computational and crystallographic data show that 3 is antiaromatic. Compound 3 was shown to react reversibly with H2 and to catalyse the hydrogenation of cyclohexene. The mechanism of catalysis was probed experimentally and computationally. peerReviewed
Hydrogen activation with perfluorinated organoboranes: 1,2,3-tris(pentafluorophenyl)-4,5,6,7-tetrafluoro-1-boraindene
The perfluorinated boraindene was synthesized and fully characterized. Both computational and crystallographic data show that is antiaromatic. Compound was shown to react reversibly with H2 and to catalyse the hydrogenation of cyclohexene. The mechanism of catalysis was probed experimentally and computationally.
CCDC 956380: Experimental Crystal Structure Determination
Related Article: Adrian Y. Houghton, Virve A. Karttunen, Warren E. Piers, Heikki M. Tuononen|2014|Chem.Commun.|50|1295|doi:10.1039/C3CC48796B
CCDC 956381: Experimental Crystal Structure Determination
Related Article: Adrian Y. Houghton, Virve A. Karttunen, Warren E. Piers, Heikki M. Tuononen|2014|Chem.Commun.|50|1295|doi:10.1039/C3CC48796B
CCDC 956383: Experimental Crystal Structure Determination
Related Article: Adrian Y. Houghton, Virve A. Karttunen, Warren E. Piers, Heikki M. Tuononen|2014|Chem.Commun.|50|1295|doi:10.1039/C3CC48796B
CCDC 956379: Experimental Crystal Structure Determination
Related Article: Adrian Y. Houghton, Virve A. Karttunen, Warren E. Piers, Heikki M. Tuononen|2014|Chem.Commun.|50|1295|doi:10.1039/C3CC48796B
CCDC 1010911: Experimental Crystal Structure Determination
Related Article: Adrian Y. Houghton, Juha Hurmalainen, Akseli Mansikkamäki, Warren E. Piers, Heikki M. Tuononen|2014|Nature Chemistry|6|983|doi:10.1038/nchem.2063
CCDC 912008: Experimental Crystal Structure Determination
Related Article: Adrian Y. Houghton , Virve A. Karttunen , Cheng Fan , Warren E. Piers , and Heikki M. Tuononen|2013|J.Am.Chem.Soc.|135|941|doi:10.1021/ja311842r
CCDC 956378: Experimental Crystal Structure Determination
Related Article: Adrian Y. Houghton, Virve A. Karttunen, Warren E. Piers, Heikki M. Tuononen|2014|Chem.Commun.|50|1295|doi:10.1039/C3CC48796B
CCDC 956382: Experimental Crystal Structure Determination
Related Article: Adrian Y. Houghton, Virve A. Karttunen, Warren E. Piers, Heikki M. Tuononen|2014|Chem.Commun.|50|1295|doi:10.1039/C3CC48796B