The Application of Simple and Easy to Implement Decoupling Pulse Scheme Combinations to Effect Decoupling of Large Values with Reduced Artifacts
Figure 3
The 31P NMR spectrum of HP(=O)(OCH2CH3)2 indicates the relative sensitivities of the resultant signal with decoupling of 1H by (a) CPD decoupling using WALTZ (PW, 60 μs; PL, 10 dB; , 1.33 Hz; DB, 10 kHz; SDB, 5 kHz); (b) CPD decoupling using GARP (PW, 60 μs; PL, 9.4 dB; , 1.35 Hz; DB, 19 kHz; SDB, 7 kHz); (c) MPF decoupling (PW, 1 ms; PL, 11.3 dB; , 1.32 Hz; DB, 28 kHz; SDB, 7 kHz); and (d) APD using CHIRP (PW, 1 ms; PL, 5.8 dB; , 1.47 Hz; DB, 44 kHz; SDB, 15 kHz). Note: the usual conditions for 1H decoupling of 13C spectra are represented by those given for (a) using WALTZ decoupling. Note that the signals present near the base of the signal for (c) marked with asterisks are not residual 1H couplings but are the 13C satellites ( = 5.69 Hz and ( = 6.20 Hz)—in this instance they are evident due to the particularly narrow base of the signal under MPF decoupling conditions but are readily discernible for other decoupling methods if 0 Hz line broadening is applied. A minor impurity signal (all cases) and sidebands (especially for MPF decoupling) are also evident.
