Pulse sequence INEPT-INADEQUATE

Schenker, K. V. and Von Philipsborn, W. Off-resonance effects and their compensation in the multiple-pulse sequences INEPT, DEPT, and INADEQUATE. J. Magn. Reson. 66 219-229, 1986. 

Kuroda and coworkers240 used a 2D INEPT-INADEQUATE sequence with a sym-metrization similar to the simple INADEQUATE used by Hengge and Schrank218 as mentioned above. Their pulse sequence... 

Crowded ID INADEQUATE spectra can be simplified by utilizing the editing properties of INEPT or DEPT249 in their combination with the INADEQUATE or by application of spectral editing as described for the 13C—13C SEMINA pulse sequence (,S MUT editing of IN AI )EQU ATE)249,250 or an INADEQUATE-SEFT combination251. 

The NMR measurements were performed in CgDj, partly mixed with toluene in order to increase solubilities. Chemical shifts are referred to TMS or CFCI3. All experiments were carried out on a Bruker 300 MSL spectrometer. Si spectra were recorded at 59.6 MHz using INEPT and INEPT-INADEQUATE pulse sequences among others. F Spectra were recorded at 282.4 MHz and H spectra at 300.1 MHz. 

The first step in increasing the signal intensity in INADEQUATE experiments is to implement a polarization transfer step. The INEPT-INADEQUATE experiment [5.162] starts with the INEPT sequence creating antiphase coherence for the sensitive nucleus with a subsequent coherence transfer step before continuing the basic INADEQUATE experiment. In Check it 5 A. 3.2 the INEPT-IN ADEQUATE pulse sequence is created and the results compared with the unrefocused ID INADEQUATE experiment. 

MHz frequency as shown. A proton spectrum occurs over a chemical shift range of 10 ppm, which corresponds to 2.5 kHz at 500 MHz. As seen in Figure 3.22, all of the protons in the sample would see 98%-100% of the power of the 500 MHz radiation delivered and all would be excited simultaneously. A pulse programmer is used to control the timing and shape of the RF pulses used to excite the sample. Square wave pulses are commonly used, but multipulse experiments and 2D NMR experiments with other pulse shapes are performed. There are hundreds of pulse sequences and 2D experiments that have been developed, with curious names like attached proton test (APT), DEPT, INEPT, INADEQUATE, COSY, and many more, some of which will be discussed later in the chapter. Each pulse sequence provides specific and unique NMR responses that enable the analyst to sort out the NMR spectrum and deduce the chemical structure of a molecule. 

The Computer. Modern computer-controlled NMR spectrometers allow the implementation of practically any sophisticated pulse sequences such as INEPT (10) or INADEQUATE (11). Very precise clock timing together with the ability to pulse simultaneously the emitter and the decoupler with their own relative rf phases are then a must for the computer. This task is appertaining to the computer pulse generator which is now a standard item on commercial systems ... 

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