Proton-Detected INADEQUATE

H detected INADEQUATE, dubbed INSIPID (/ adequate Sensitivity /mprovement by Proton Detection)241, has not been applied to (29Si-29Si) INADEQUATE, but its combination with INEPT excitation might be useful when sensitivity is the most important... 

Closely related to proton detected INADEQUATE is 1,1-ADEQUATE252 which, if applied to polysilanes, would show 1H—29Si correlations between the chemical shift of the protons coupled to Si-1 and the chemical shift of Si-2, that is 7(29Si—29Si) coupled to Si-1. 

The INADEQUATE experiment, developed by Bax et alwill not be presented due to its lack of sensitivity, it is seldom used and this is why little will be said about its processing. A computer program called COSMIC developed by Richardz et which analyses spectra and produces carbon connectivity lists as an output is, however, worthy of mention. The introduction of pulse field gradients made it possible to design much more sensitive proton detection sequences that are quite suitable for the construction of spin networks and structure determination," even if they work only with those carbons that are directly bound to protons. 

X-X INADEQUATE problems when X has low natural abundance can be improved with proton detection H-X-X-H methods... 

Due to its inherent insensitivity the important direct 2D experiment for tracing of the carbon skeleton - INADEQUATE (incredible natural abundance double quantum transfer experiment), based on measurement of doubly C-labeled species needs, unless enriched, a large quantity of the compound under investigation. In favorable cases the proton-detected analoge ADEQUATE could be applied. 

Scheme 3 a) H-X cross polarized INADEQUATE sequence to detect X-X correlation, b) CPMG sequence (allowing a shorter experiment time for nuclei with a long relaxation time). homonuc. h Dec. corresponds to homonuclear proton decoupling. 

Figure 5.79. (A) In heteronuclear relayed proton correlated spectroscopy (HERPECS), the coherence is transferred first from to a heteronuclear spin, X, and is then relayed and detected at the third nucleus, Hg. (B) A schematic representation of INADEQUATE, H,H-COSY, and H,C-COSY, relayed H,C-COSY, H,C-COLOC, and HERPECS experiments.

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