Solid-state NMR and diffraction studies of p-tert-butylcalix[4]arene·nitrobenzene·xe non

Characterization of dynamic processes using deuterium in uniformly 2H,13C,15N enriched peptides by MAS solid-state NMR

“…The presented data are based on 2D 2 H, 13 C correlation experiments and can easily be extended to 3D 2 H, 13 C, 13 C experiments, if chemical shift dispersion in the carbon spin system is critical. The pulse sequences are sketched in Fig.…”

“…1C), a 2 H p-pulse was implemented followed by a delay D which was varied from 1 ms to 1.5 s prior to the 2 H p/2 read-out pulse. Typically, we employ recycle delays on the order of 250 ms for 2D 2 H, 13 C correlation experiments and on the order of 3 s for T 1 experiments. In case of spectral overlap, a RFDR 13 C, 13 C mixing together with a second indirect chemical shift evolution period t 1 on 13 C can be optionally implemented.…”

“…Typically, we employ recycle delays on the order of 250 ms for 2D 2 H, 13 C correlation experiments and on the order of 3 s for T 1 experiments. In case of spectral overlap, a RFDR 13 C, 13 C mixing together with a second indirect chemical shift evolution period t 1 on 13 C can be optionally implemented. Typical 13 C, 13 C mixing times are on the order of 50 ms.…”

“…Three categories of motion can be distinguished [13]. Slow motion: the frequency of motion is greater than the quadrupolar coupling interaction (10 2 > s C > 10 À4 s).…”

“…We present in this paper 2 H, 13 C MAS correlation experiments that were performed on a uniformly 2 H, 13 C, 15 N labeled sample of Nac-Val, and on the uniformly 2 H, 15 N labeled dipeptide (Nac-Val-Leu-OH). The experiments involve the measurement of the 2 H tensor parameters by evolution of the 2 H chemical shift, as well as the measurement of 2 H T 1 relaxation times at two different magnetic fields.…”