FOUR SHIFT entity

Figure 5.3 Entity FOUR SHIFT and the libraries/packages required for the general form of the shift register.

The DEPT experiment, or distortionless enhanced polarization transfer, is a carbon selectivity experiment. ° ° ° Depending on the pulse length selected, one can selectively observe different types of carbon entities. We recommend setting the DEPT proton pulse length to 135°. In this case, quarternary carbons are suppressed, methylenes are inverted, and methine and methyl carbons appear upright. Methines and methyls are distinguished based on chemical shift and 2D proton correlations. Methines usually appear downfield of methyls. Alternatively, if time permits, the entire series of DEPT experiments can be performed to conclusively distinguish methine from methyl resonances. One second is a reasonable default value for the recycle time. The spectrum should be set to capture the resonances of interest with 32-64 K data points and four dummy scans. While this is an easily interpreted data set, the multiplicity edited HSQC provides much more robust information, both multiplicity as well and the one-... 

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