Homonuclear decoupled proton

Figure 1.8. Homonuclear decoupling of the CH protons of 3-aminoacrolein (CDaOD, 25 C, 90 MHz), (a) H NMR spectrum (b) decoupling at Sh = 8.5 (c) decoupling at = 7.3. At the position of the decoupled signal in (b) and (c) interference beats are observed because of the superposition of the two very similar frequencies...

Proton-proton homonuclear decoupling has been performed by the ESLG decoupling sequence [46]. Quadrature detection in coj was achieved by using the time proportional phase increment method (TPPI) [47]. During the acquisition period, two pulse phase modulation (TPPM) heteronuclear decouphng ]48] was applied (Figure 7.6). 

Fig. 11. Single-spin double-resonance experiment for the calibration of irradiation power. The proton line in chloroform is irradiated with the homonuclear decoupler. The strong central feature is at the irradiation frequency, and the separation of the two satellites is...

Using time-dependent perturbation theory and taking full account of the symmetry and commutation relations for the high-order dipolar Hamiltonians, Hohwy et al.61 69 gave a systematic analysis of homonuclear decoupling under sample rotation and proposed a novel approach to the design of multiple-pulse experiments. Based on the theoretical analysis, they proposed a pulse sequence that can average dipolar interaction up to the fifth order. One example of these pulse sequences is shown at the top of Fig. 3. This sequence is sufficiently powerful that it is possible to obtain precise measurement of proton chemical shift anisotropies, as shown in Fig. 3. 

Figure 13 Pulse sequence for the solid-state 31P—1H frequency-switched Lee-Goldburg (FSLG) experiment. Proton-proton homonuclear decoupling was performed by using the FSLG decoupling sequence. Quadrature detection in Wi was achieved by using the TPPI method. During the acquisition period, TPPM heteronuclear decoupling was applied.

All of the protons in each of 12 thermo- and photochromic BIPS were assigned through a combination of homonuclear decoupling experiments and correlation spectroscopy. The relative stereochemistry of the gem-dimethyl groups could be assigned on the basis of Nuclear Overhauser Effect (NOE) experiments.131... 

---