The −OOC-ĊH-COO− radical trapped in a γ-irradiated single crystal of potassium hydrogen (KH) malonate is investigated at room temperature by ESR and ENDOR spectroscopy. The α-proton and 13C hyperfine tensors show that the free radical is oriented in the monoclinic crystal lattice with its Ċ-H bond along the twofold symmetry axis b. ENDOR spectra allow the determination of the superhyperfine interactions of the protons of neighboring molecules and hydrogen-bonded protons. The covalent character of the “very short” hydrogen bond present in the KH malonate crystal structure is discussed. An analysis of the factors affecting the intensity ratios of the two ENDOR transitions of the a proton is performed.
ESR and ENDOR Studies of gamma-Irradiated Single Crystals of Potassium Hydrogen Malonate
BRUSTOLON, MARINA ROSA;
1978
Abstract
The −OOC-ĊH-COO− radical trapped in a γ-irradiated single crystal of potassium hydrogen (KH) malonate is investigated at room temperature by ESR and ENDOR spectroscopy. The α-proton and 13C hyperfine tensors show that the free radical is oriented in the monoclinic crystal lattice with its Ċ-H bond along the twofold symmetry axis b. ENDOR spectra allow the determination of the superhyperfine interactions of the protons of neighboring molecules and hydrogen-bonded protons. The covalent character of the “very short” hydrogen bond present in the KH malonate crystal structure is discussed. An analysis of the factors affecting the intensity ratios of the two ENDOR transitions of the a proton is performed.Pubblicazioni consigliate
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