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Metal-free dihydrogen activation chemistry: structural and dynamic features of intramolecular P/B pairs.
- Source :
-
Dalton transactions (Cambridge, England : 2003) [Dalton Trans] 2009 Mar 07 (9), pp. 1534-41. Date of Electronic Publication: 2009 Jan 20. - Publication Year :
- 2009
-
Abstract
- Hydroboration of allyl(dimesityl)phosphane with HB(C(6)F(5))(2) gives the intramolecular five-membered P-B Lewis pair 7, that was characterized by X-ray diffraction. Similarly, HB(C(6)F(5))(2) addition to the substrates (mesityl)(2)P-CR[double bond, length as m-dash]CH(2) (R = CH(3), Ph) yield the corresponding (mesityl)(2)P(micro-CHRCH(2))B(C(6)F(5))(2) products 9a (R = CH(3)) and 9b (R = Ph) that show a weak intramolecular P...B interaction. The activation energy of the (reversible) P...B cleavage of these substrates was determined by dynamic (19)F NMR spectroscopy (9a: Delta G(not equal)(inv) (280 K) = 11.7 +/- 0.4 kcal mol(-1)). Compounds 9b and 9c show similar values. Compound 9c was prepared by HB(C(6)F(5))(2) addition to (mesityl)(2)P-CH=CHSiMe(3). Compound 9a reacts rapidly with dihydrogen (2.5 bar) at room temperature in pentane to give the zwitterionic H(2)-activation product (mesityl)(2)PH(+)(micro-CHMeCH(2))BH(-)(C(6)F(5))(2) (11).
Details
- Language :
- English
- ISSN :
- 1477-9226
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- Dalton transactions (Cambridge, England : 2003)
- Publication Type :
- Academic Journal
- Accession number :
- 19421595
- Full Text :
- https://doi.org/10.1039/b815832k