13C Nuclear magnetic resonance spectrum

Fig. 3.51 13C nuclear magnetic resonance spectrum at hex-l-ene in CDC13 sweep width 200 p.p.m. Data reproduced from the Standard Carbon-... 

Fig. 3.52 13C nuclear magnetic resonance spectrum of crotonaldehyde in CDClj sweep width 250 p.p.m. 

Fig. 3.74(a) 13C nuclear magnetic resonance spectrum of butane-1,3-diol in CDC13 signal assignment by off-resonance decoupling. 

C Nuclear Magnetic Resonance Spectrum of Juvenile Hormone III... 

Figure 15.9. 13C CPMAS NMR spectrum of humin extracted from a brown chernozem soil from Western Canada. The characteristic doublet in the unsubstituted aliphatic region is characteristic of methylene carbon (28-34 ppm) and shows the presence of both amorphous (soft) domains at 29 ppm and crystalline (rigid) domains at 33 ppm in soil humin. Reprinted from Simpson, M. I, and Johnson, R C. E. (2006). Identification of mobile aliphatic sorptive domains in soil humin by solid-state 13C nuclear magnetic resonance. Environ. Toxi. Chem. 25, 52-57, with permission from the Society of Environmental Toxicology and Chemistry.

The carbon nuclear magnetic resonance spectrum of lomefloxacin mesylate obtained in D2O at 25°C is given in Figure 7 (9). The spectrum was obtained on a Bruker AM-500 NMR Spectrometer operating at 125.76 MHz and was referenced to external TSP [3-(trimethylsilyl)propionic-2,2,3,3-d4 acid]. The 13C spectrum was obtained with proton broad-band decoupling and the carbon assignments for lomefloxacin were made using a combination of 1-D and 2-D NMR techniques. 

The diamagnetic, monomeric thorium derivative has been completely characterized by its 1h and 13C nuclear magnetic resonance spectra. Data are shown in Table II. In particular the NMR spectrum, proton-coupled, shows a triplet pattern clearly due to splitting by two equivalent hydrogen atoms. The uranium metallocycle is paramagnetic (yg = 2.7 B.M.) and we have only observed its NMR spectrum. A titanium metallocycle,... 

FIGURE 2.12 Results of variable contact time (VCT) experiments for the aromatic peak in the cross-polarization (CP)/magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectrum of a lignite sample. The solid line is a fit to Equation (2.17). (Reproduced from Pan, V.H., and Maciel, G.E. The analysis of three representative premium coals by 13C nuclear magnetic resonance. Fuel 1993 72(4) 451-468. With permission from Elsevier.)... 

The 111 NMR, 13C NMR (NMR - nuclear magnetic resonance), infrared (IR), ultraviolet (UV), and mass spectrometry (MS) data have been reported for the first example 5 of a 2/7-azepin-2-one (2-azatropone). The carbonyl group stretching frequency appeared at 1682 cm 1 in the IR spectrum of the neat material <2000JOC6093>. Further H and 13C NMR spectroscopic data on azepine derivatives have been summarized by Smalley <1997HOU(E9d)108>. 

Nuclear Magnetic Resonance (NMR) Spectroscopy is by far the most widely used analytical technique in the modern organic chemistry lab. Numerous monographs have been written on this subject. It would be impossible to cover all of the significant points here. The reader who is interested in knowing what the proton ( H) or carbon (13C) spectrum of a particular compound is directed to the Aldrich Library of NMR Spectra or the Sadtler Library. 

Nuclear magnetic resonance (NMR) spectroscopy is also largely used to characterize C02 complexes. The 13C NMR spectrum of C02 dissolved in a nonpolar solvent shows a resonance at 124ppm, which is shifted when C02 is bonded to a metal center. Depending on the mode of bonding, the shift may be up or down field, and may vary from a few ppm up to several hundreds of ppm. A few examples are given below for different types of bonding. 

The 125 MHz -decoupled 13C spectrum of cholesterol is shown in Figure 1.26. Because the 13C nuclear magnet is only about one fourth as strong as the nuclear magnet, the 13 C resonant frequency is always about one fourth of the 1H frequency in the same magnetic field. Thus on a 500 MHz NMR spectrometer (i.e., an 11.74 T B0 field in which H resonates at 500 MHz) the 13C frequency is about 125 MHz. The CDCI3 peaks (a 1 1 1... 

An illustration in PR shows, as a small icon of spectroscopic progress, the improvement in sensitivity of nuclear magnetic resonance spectrometry. In only 15 years, the solid-state 13C spectrum of adaman-tane, with only two types of carbons, CH and CH2, had turned from inaccessibility to an easy routine. Such solid-state 13C spectra became important diagnostic tools for the chemical industry in the areas of polymers, whether as elastomers, textile fibers, or plastics such as polypropylene. 

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