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·ÖÏíÎÄÏ×һƪ NMR Solvents The Observation of ¡°Double Water Peaks¡± in Deuterated NMR Solvents ÄÚÈݽéÉÜ£º Generally speaking, water takes three forms in a deuterated solvent environment: HOH, HOD, and DOD. In the proton NMR spectrum of a pure NMR solvent, both the HOH and HOD peaks are observed, but not the DOD. In a proton NMR Spectrum, HOH appears as a singlet. However, due to coupling from the D nucleus which has a nuclear spin quantum number I = 1, HOD appears as a triplet. The observed splitting 2JHD of the HOD peak is about 1-2 Hz. The chemical environments of the protons in HOH and HOD are similar, but not identical. Therefore, the HOH and HOD peaks appear to be close in chemical shift, but not overlapped. They are typically 0.03 ppm apart. HOD Peaks - NMR spectra of ¡°neat¡± deuterated solvent always exhibit a peak due to H20 in addition to the residual solvent peak. When the exchange rate between H20 and HDO is slow on the NMR timescale the water peak appears as two peaks, a singlet corresponding to H20 and a 1:1:1 triplet corresponding to HDO. ×ÔÎÒÆÀ¼Û£º ±¾ÌûÖ÷Òª½²Ë®·åÁÑ·ÖµÄÔÒò¡£ºÍÁ½¸öË®·åµÄÔÒò¡£ ¾ßÌåÄÚÈݼû¸½¼þ¡£»òÕßµã»÷ÒÔÏÂÍøÖ·ÏÂÔØhttp://www.sigmaaldrich.com/etc/ ... ble_water_peaks.pdf ÓÐÓõϰÇë´ó¼Ò¸úÌûÖ§³Ö£¬Ð»Ð» [ Last edited by bobo0621 on 2009-1-8 at 22:40 ] |
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ÄÚÈݽéÉÜ£º
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ÄÚÈݽéÉÜ£º Generally speaking, water takes three forms in a deuterated solvent environment: HOH, HOD, and DOD. In the proton NMR spectrum of a pure NMR solvent, both the HOH and HOD peaks are observed, but not the DOD. In a proton NMR Spectrum, HOH appears as a singlet. However, due to coupling from the D nucleus which has a nuclear spin quantum number I = 1, HOD appears as a triplet. The observed splitting 2JHD of the HOD peak is about 1-2 Hz. The chemical environments of the protons in HOH and HOD are similar, but not identical. Therefore, the HOH and HOD peaks appear to be close in chemical shift, but not overlapped. They are typically 0.03 ppm apart. HOD Peaks - NMR spectra of ¡°neat¡± deuterated solvent always exhibit a peak due to H20 in addition to the residual solvent peak. When the exchange rate between H20 and HDO is slow on the NMR timescale the water peak appears as two peaks, a singlet corresponding to H20 and a 1:1:1 triplet corresponding to HDO. ×ÔÎÒÆÀ¼Û£º ±¾ÌûÖ÷Òª½²Ë®·åÁÑ·ÖµÄÔÒò¡£»òÁ½¸öË®·åµÄÔÒò¡£ [ Last edited by bobo0621 on 2008-12-23 at 13:45 ] |
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