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L EWIS A CID / B ASE S TABILIZED P HOSPHANYLBORANES

L EWIS A CID / B ASE S TABILIZED P HOSPHANYLBORANES. Ariane Adolf, University of Regensburg, Germany. Introduction New Lewis acid/base stabilized phosphanylboranes with main group Lewis acids New routes to Lewis base stabilized phosphanylboranes Reactivity of PH 2 BH 2 NMe 3.

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L EWIS A CID / B ASE S TABILIZED P HOSPHANYLBORANES

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  1. LEWISACID/BASESTABILIZEDPHOSPHANYLBORANES Ariane Adolf, University of Regensburg, Germany

  2. Introduction New Lewis acid/base stabilized phosphanylboranes with main group Lewis acids New routes to Lewis base stabilized phosphanylboranes Reactivity of PH2BH2NMe3 Lewis acid/base stabilized phosphanylboranes

  3. Introduction Monomeric parent compound of phosphanylboranes Without stabilization: head-to-tail polymerization

  4. Introduction Two types of stabilization via sterical hindrance via electronic saturation P.P.Power, Chem. Rev. 1999, 99 , 3463 – 3503. R.T. Paine, H. Nöth, Chem. Rev. 1995, 95 , 343 – 379. M. Scheer, U. Vogel, A. Y. Timoshkin, P. Hoemensch, Chem. Eur. J.2003, 9, 515. J.-M. Denis et al., Chem. Commun.2003, 54 – 55.

  5. Introduction • Lewis base stabilized, monomeric group 13/15 compounds R. A. Jones, A. H. Cowley et al., Organometallics1993, 12, 17 – 18. S. Schulz et al., Eur. J. Inorg. Chem. 2001, 1, 161 – 166.

  6. Introduction • Synthesis of a Lewis acid/base stabilized phosphanylborane M. Scheer , U. Vogel, A. Y. Timoshkin, P. Hoemensch, Chem. Eur. J.2003, 9, 515.

  7. New Lewis acid/base stabilized phosphanylboranes E = B, R = H, Ph E = Ga, R = H, Ph, Cp* (C5Me5) E = B: d(P-B)= 1.989(4) Å E = Ga: d(P-B)= 1.992(2) Å E = Ga: d(P-B)= 1.963(2) Å E = B: d(P-B)= 1.974(3) Å d(P-B)= 1.946(11) Å View along the B – P bond axis (E = B, Ga) M. Scheer, A. Adolf, M. Zabel, Eur. J. Inorg. Chem.2007, article in press.

  8. New Lewis acid/base stabilized Phosphanylboranes • In the solid state: both enantiomers are present in the unit cell View along the P – B bond axis

  9. New Lewis acid/base stabilized Phosphanylboranes • Synthesis via H2 elimination d(P-B)= 1.982(4) Å View along the B−P bond axis

  10. New Lewis acid/base stabilized Phosphanylboranes • Synthesis via Lewis base substitution d(P-B) = 1.979(2) Å

  11. New routes to Lewis base stabilized Phosphanylboranes • Route I: removal of the Lewis acid Ga(C6F5)3 31P NMR spectrum (CD2Cl2) d = -99.78 ppm, dd, 1JPH = 212 Hz, 1JPB = 37 Hz (Educt: d = -77.9 ppm, d, 1JPH = 328 Hz) MS (EI, 70 eV): m/z = 181.1 (M+, 3.9 %), 121.1 (dmap-H+, 82.4 %)

  12. New routes to Lewis base stabilized Phosphanylboranes • Route I: removal of the Lewis acid W(CO)5 31P NMR spectrum (C6D6): d = -215.5 ppm, td, 1JPH = 189 Hz, 1JPB = 32 Hz d(P-B)= 1.976(2) Å K.-C. Schwan, A. Y. Timoshkin, M. Zabel, M. Scheer, Chem. Eur. J. 2006, 12, 4900.

  13. New routes to Lewis base stabilized phosphanylborabes • Route II: direct synthesis via metathesis reaction

  14. New routes to Lewis base stabilized Phosphanylboranes • Route III: depolymerization 31P NMR spectrum (C6D6): d = -87.8 ppm, d, 1JPH = 187 Hz, 1JPB= 27.5 Hz MS (EI, 70 eV): m/z = 246.3 (M+, 6.7%), 137.2 (carbene BH2+, 100%) I. Manners et al., Angew. Chem. 1999, 111, 3540.

  15. Reactivity of PH2BH2NMe3 M. Scheer, K.-C. Schwan, A. Y. Timoshkin, M. Zabel, Chem. Eur. J. 2006, 12, 4900.

  16. Reactivity of PH2BH2NMe3 M. Scheer, K.-C. Schwan, A. Y. Timoshkin, M. Zabel, Chem. Eur. J. 2006, 12, 4900.

  17. Reactivity of PH2BH2NMe3 • (OH)2P(O)BH2NMe3 in the solid state

  18. Reactivity of PH2BH2NMe3 • J.-M. Denis et al. • first attempts of polymerization J.-M. Denis et al., Chem. Commun.2003, 54 – 55.

  19. Acknowledgment • Prof. Manfred Scheer • Our research group • The University of Regensburg • You for your kind attention

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