Protons high-resolution spectra

The additional detail provided by a high resolution spectrum allows more information to be determined about the structure of the compound. Analysing the multiplets allows the neighbouring proton environment to be identified. This can be done using the n + 1 rule, where n is the number of carbon atoms attached to the next-door carbon atom and n + 1 is the number of peaks that will be seen in the cluster. 

Owing to the differences in both the nature and magnitude of the homo-and hetero-nuclear dipolar interactions, the process of eliminating the dipolar interactions to obtain a high resolution spectrum in the solid state is slightly different for protons and carbons, respectively, and will be reviewed separately in following... 

It is assumed that all of the relaxation processes with apparent time constants of 10 m.sec. to 2 sec. derive from water protons. In the case of samples containing large amounts of liquid fat, dissolved oligosaccharides or amino acids, this may not be the case, since C-H proton relaxation rates fall within this range. Some other measurement (e.g. integration of the high resolution spectrum) may be necessary to correct for this potentially major source of error. 

To determine if alkylation had occurred on nonprotonated carbons, another high-resolution spectrum was obtained with the proton decoupler turned off. The two CD3 resonances remained broad the peak at 8 36 and... 

Predict the appearance of the high-resolution ( spectrum of (proton decoupled)... 

Like the paramagnetic species were overlapped in the same spectrum, apart from the difficulty of obtaining a high-resolution spectrum that allowed the observation of the splitting due to the functional group protons, it was impossible to identify the functional group that substituted the hydrogen atoms. 

Figure 24.5 shows the high-resolution spectrum of 2-propanol dissolved in deuterated chloroform. Because of solvent interaction, the donblet from the hydroxyl proton occurs near 2 ppm instead of farther downfield. We discuss this effect later when we discuss ethanol. The group of peaks near 4 ppm is from the -CH- proton. The 14 fines overlap and are not completely resolved. The intense doublet near 1.3 ppm is from the six methyl protons. 

At the left side of Fig. 2b are shown three peaks corresponding to the methylene carbon CH2 in adamantane, split by its two attached protons. The manner in which these two protons split the carbon energy levels is indicated at the center of Fig. 2b. One proton supplies the same type of splitting as shown for the methyne carbon, and the second proton further splits that level as indicated. The transitions associated with this splitting are indicated by the bathroom tile diagram, at frequencies /s, /4, and /s. Note that there are two equivalent transitions at f, so the intensity of the center line will be twice that of the two satellites. This experimental result is found in the high-resolution spectrum, shown on the lower left side of Fig. 2b. 

Fig. 1. High-resolution spectrum of ATP. (a) 1959 Single-scan, 24.3-MHz, 5-mm tube, continuous-wave operation of a Varian 4302 dual-purpose NMR spectrometer. [ATP] = 500 mM. (b) 1976 10 scans, 72.9 MHz, 20-mm tube, in the Fourier-transform mode of operation, 20-sec repetition rate, and proton decoupling on a Bruker WH 180 NMR spectrometer. [ATP] = 1 mM. From Cohn (1979).

Figure 7.11 Methylene proton portion of the 220-MHz NMR spectrum of poly(methyl methacrylate) (a) predominately syndiotactic and (b) predominately isotactic. [From F. A. Bovey, High Resolution NMR of Macro molecules, Academic, New York, 1972, used with permission.]...

The 5 Hz optimized l,n-ADEQUATE spectrum of strychnine (1) is shown in Figure 9.70 The high resolution 600 MHz proton spectrum is shown in Figure 10A and compared to slices extracted at the Fi frequency of the C15 methylene resonance in the 5 Hz optimized l,n-ADEQUATE spectrum (B) and the 60 Hz optimized 1,1-ADEQUATE spectrum (C). The adjacent carbons (via Vcc) show correlations in the 5 Hz optimized INADEQUATE spectrum that are unsuppressed but all possible three-bond... 

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