Alkyl Radicals as Hydrogen Bond Acceptors: Computational Evidence
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Alkyl Radicals as Hydrogen Bond Acceptors: Computational Evidence. / Hammerum, Steen.
In: Journal of the American Chemical Society, Vol. 131, 2009, p. 8627-35.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Alkyl Radicals as Hydrogen Bond Acceptors: Computational Evidence
AU - Hammerum, Steen
PY - 2009
Y1 - 2009
N2 - Spectroscopic, energetic and structural information obtainedby DFT and G3-type computational studies demonstrates that chargedproton donors can form moderately strong hydrogen bonds to simplealkyl radicals. The presence of these bonds stabilizes the adductsand modifies their structure, and gives rise to pronounced shifts ofIR stretching frequencies and to increased absorption intensities. Thehydrogen bond acceptor properties of alkyl radicals equal those of manyconventional acceptors, e.g., the bond length changes and IR red-shiftssuggest that tert-butyl radicals are slightly better acceptors thanformaldehyde molecules, while propyl radicals are as good as H2O. Thehydrogen bond strength appears to depend on the proton affinity of theproton donor and on the ionization energy of the acceptor alkyl radical,not on the donor-acceptor proton affinity difference, reflecting that thecharge-transfer aspects of hydrogen bonding are particularly conspicuouswhen the acceptor polarity and basicity is low. Udgivelsesdato: 2 juni 2009
AB - Spectroscopic, energetic and structural information obtainedby DFT and G3-type computational studies demonstrates that chargedproton donors can form moderately strong hydrogen bonds to simplealkyl radicals. The presence of these bonds stabilizes the adductsand modifies their structure, and gives rise to pronounced shifts ofIR stretching frequencies and to increased absorption intensities. Thehydrogen bond acceptor properties of alkyl radicals equal those of manyconventional acceptors, e.g., the bond length changes and IR red-shiftssuggest that tert-butyl radicals are slightly better acceptors thanformaldehyde molecules, while propyl radicals are as good as H2O. Thehydrogen bond strength appears to depend on the proton affinity of theproton donor and on the ionization energy of the acceptor alkyl radical,not on the donor-acceptor proton affinity difference, reflecting that thecharge-transfer aspects of hydrogen bonding are particularly conspicuouswhen the acceptor polarity and basicity is low. Udgivelsesdato: 2 juni 2009
KW - Faculty of Science
U2 - 10.1021/ja901854t
DO - 10.1021/ja901854t
M3 - Journal article
C2 - 19489573
VL - 131
SP - 8627
EP - 8635
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
ER -
ID: 16131059