³H¹H shift correlation NMR spectroscopy

Abstract

Three two-dimensional 'H-lH chemical shift correlation experiments are described, all using familiar pulse sequences. The experiments reveal the chemical shifts of the 'H spins which are coupled scalarly to a 'H spin and, thus, assist in the unambiguous location of this 'H spin within the molecule. The limitations for molecules involving a 'H spin which is coupled differently to various 'H spins are indicated. In practice, the detection limit is of the order of 100 MBq per 3H-labelliig site.

Improved methods for1H-3H heteronuclear shift correlation

“…This experiment can be very useful in cases where connectivity involving specific, known J-couplings is desired. 16,17 However, the information content of the spectrum in Fig. 6 is inferior obtained from the hetero-TOCSY and HOESY experiments because of the need to optimize for a given coupling constant.…”

“…12 -15 Figure 1(D) depicts a pulse-interrupted free-precession HET-COR previously method applied to 1 H-3 H spin systems, and compared here to the improved techniques. 16,17 All experiments use WALTZ-16 broadband decoupling during acquisition. 18 For 2D sequences, heteronuclear decoupling in the indirectly detected dimension is accomplished with pulses during the t 1 periods.…”

“…The pulse-interrupted free-precession HETCOR sequence was run as described in the literature and results are presented in the magnitude mode. 16,17 Delays of  1 D 56 ms and  2 D 37 ms were used to maximize the coherence transfer for typical coupling constants, as discussed below. A total of 32K complex points were acquired in the 1D experiments.…”

Tritium NMR: A compilation of data and a practical guide

“…The 3 H NMR spectra of [6,7-3 H]-11α-hydroxy-19-nortestosterone: (a) 1 H decoupled 3 H NMR one-dimensional spectrum; (b) 1 H decoupled 3 H-3 H correlation contour plot; (c-e) 3 H-1 H correlation contour plots, obtained using pulse sequences presented in Figure 7a-c, respectively. Reproduced with minor editing privilege from Funke et al [24] with the permission of John Wiley and Sons means of the longitudinal proton and tritium relaxation measurements. A specific tritium labeling of the succinyl part of this tripeptide, as was shown by tritium NMR spectra and presented in Figure 19, allowed the measurement of the cross-relaxation rates of the individual tritium spin pairs in the inhibitor-enzyme complex, as well as in a free inhibitor itself.…”

“…This is exemplified here with three dedicated pulse sequences shown in Figure 7 when applied for the monotritiated dimethyl sulfoxide. [24] It can be seen in Figure 7a that all 3 H-1 H couplings are present, in Figure 7b these couplings are F I G U R E 5 Proton decoupled tritium J-resolved spectra of n-propylbenzene in αand β-CH 2 ranges; see original publication for details. Reproduced with minor editing privilege from Williams et al [23] with the permission of the American Chemical Society removed in one dimension, and in Figure 7c they are removed in both dimensions.…”