- Effects of spin diffusion on spin-lattice relaxation in solid-state 2H MAS NMR spectroscopy
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Recently, there has been increased interest in using 2H MAS NMR spectroscopy as an alternative to 'static' quadrupolar-echo NMR for studying dynamics in solids. Here we show that the phenomenon of enhanced spin diffusion as a result of n = 0 rotational resonance can lead to observation of a common spin-lattice (T1) relaxation time for all deuterons. Thus, if rapidly relaxing groups are present, such as -CD3 or - ND3+ groups, then even highly immobile deuterons can exhibit T1 relaxation times of ～1 s under MAS conditions, greatly facilitating data acquisition.
- Cutajar, Marica,Lewis, Moira H.,Wimperis, Stephen
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- Isotope-coded, fluorous photoaffinity labeling reagents
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A pair of isotope-coded, fluorous photoaffinity labeling reagents has been developed and coupled with a peptide. The modified peptides form adducts with methanol upon light illumination, which show characteristic isotope labeling patterns in mass spectra and can be separated from other peptides through fluorous silica. The Royal Society of Chemistry 2012.
- Song, Zhiquan,Huang, Weigang,Zhang, Qisheng
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scheme or table
p. 3339 - 3341
(2012/05/04)
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- Novel Transannular Reactions in the Acid Hydrolysis of Diazotized syn- and anti-4-Amino(1,4)naphthalenoparacyclophanes
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The diazonium ions derived from the title syn- and anti-4-aminocyclophanes 1a und 4a in aqueous solution undergo transannular reactions to give 17-hydroxy(1,4)naphthalenoparacyclophane 3a and 9,10-dihydro-1,9:4,10-diethano-9,10-ethenoanthracene 6a, respectively.Deuterium-tracer experiments suggest that the reaction of diazotized 1a proceeds via a pathway involving tranannular diazo coupling followed by generation of a 16,17-didehydro intermediate.On the other hand, the reaction pathway of diazotized 4a involves dediazonization followed by transannular electrophilic addition.
- Takada, Yoshihiro,Tsuchiya, Kazuhiko,Takahashi, Senji,Mori, Nobuo
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p. 2141 - 2145
(2007/10/02)
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