ANGLE-SELECTED ENDOR SPECTROSCOPY .1. THEORETICAL INTERPRETATION OF ENDOR SHIFTS FROM RANDOMLY ORIENTATED TRANSITION-METAL COMPLEXES
ANGLE-SELECTED ENDOR SPECTROSCOPY .1. THEORETICAL INTERPRETATION OF ENDOR SHIFTS FROM RANDOMLY ORIENTATED TRANSITION-METAL COMPLEXES
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DOI：
10.1021/ja00311a012
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发表时间：
1985-01-01
影响因子：
15
通讯作者：
KREILICK, RW
中科院分区：
文献类型：
--
作者：
HURST, GC;HENDERSON, TA;KREILICK, RW
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The NMR lines from ligand nuclei in paramagnetic transition-metal complexes are shifted because of the dipolar and Fermi contact interactions with the unpaired electron (s) of the metal ion. The dipolar interaction depends on the position of the nuclear spin with respect to the metal ion, and dipolar shifts can be analyzed to yield nuclear positions. This paper demonstrates how ESR spectra of randomly oriented molecules can be Used to select molecular orientations. ENDOR spectra taken at orientations selected by ESR can then be used to determine nuclear positions and Fermi contact energies. A theoretical development of the equations for the shifts of ENDOR lines in randomly oriented solids is also given. This theory shows that the equations which have commonly been used to analyze ENDOR from these samples are incorrect and unable to account for many of the experimental features of the ENDOR spectra.The electron spin of transition-metal ions interacts with ligand nuclear spins via dipolar and Fermi contact interactions, producing shifts in the NMR lines of the ligand nuclei. 1 The dipolar interaction depends on the relative position of the nuclear spin with respect to the metal atom, and the NMR spectra of solid samples can be analyzed to yield information about nuclear co-ordinates. NMR spectroscopy of solid paramagnetic samples has limited sensitivity so one can only examine relatively concentrated