Recent Publications

Accurate O−H Bond Dissociation Energy Differences of Hydroxylamines Determined by EPR Spectroscopy: Computational Insight into Stereoelectronic Effects on BDEs and EPR Spectral Parameters

Paul S. Billone, Paul A. Johnson, Shuqiong Lin, J. C. Scaiano, Gino A. DiLabio, and K. U. Ingold, “Accurate O−H Bond Dissociation Energy Differences of Hydroxylamines Determined by EPR Spectroscopy: Computational Insight into Stereoelectronic Effects on BDEs and EPR Spectral Parameters”, J. Org. Chem., 76 (2), 631-636 (2011); Dec. 2010.

Accurate O−H Bond Dissociation Energy Differences of Hydroxylamines Determined by EPR Spectroscopy

Differences in O−H bond dissociation enthalpies (ΔBDEs) between the hydroxylamine of 15N-labeled TEMPONE and 10 N,N-di-tert-alkyl hydroxylamines were determined by EPR. These ΔBDEs, together with the g and aN values of the derived nitroxide radicals, are discussed in relation to various geometric, intramolecular dipole/dipole, and steric effects and in relation to the results from DFT calculations. We find that dipole/dipole interactions are the dominant factors in dictating aN values and O−H BDEs in all of these structurally similar nitroxides and hydroxylamines, respectively. The importance of including the Boltzmann distribution of conformations for each nitroxide in the aN calculations is emphasized.
http://pubs.acs.org/doi/abs/10.1021/jo1021794