The Application of Simple and Easy to Implement Decoupling Pulse Scheme Combinations to Effect Decoupling of Large Values with Reduced Artifacts

Of the various problems in decoupling one nucleus type from another using standard decoupling pulse schemes for broadband decoupling, a particular challenge is to effect full, artifact-free decoupling when the size of the coupling constant is very large. Herein it is demonstrated that 1H decoupling of the 31P NMR spectrum of diethyl phosphonate HP(=O)(OCH2CH3)2 can be accomplished with reduced artifacts despite the large value of 693 Hz by using a combination of decoupling pulse schemes involving continuous-wave (CW) irradiation and either adiabatic-pulse decoupling (APD), MPF decoupling, or traditional composite-pulse decoupling (CPD) schemes such as WALTZ or GARP. The considered strategy is simple, efficient, and easy to implement on most instruments. The best result was attained for a combination of CW and CPD using GARP with a standard pulse width of 60 μs. Altogether, the advantages of the methodology include low power requirements, complete decoupling, tolerance of a range of large values, large bandwidth for normal-sized values, and the suppression of sidebands.