NMR satellites

Half-integer quadrupolar nuclei NMR central transition, 1, 457, 1, 464 NMR satellite transitions, 1, 455 Half-sandwich complexes... 

NMR satellites can be used to differentiate between fluxional tr-and TT-bonded cyclopentadienyl groups. It is found that for a 7r-bonded cyclopentadienyl group — H) is between 174 and 181 Hz, but for a fluxional bonded cyclopentadienyl group — H) is between 159... 

NMR satellites have also been used to demonstrate that [(RC5H0Fe(CO)2CH=CH—CH=CHFe(CO)2(C5H4R )] (R,R = H or Me) is fluxional with 1,3-shifts of the metal-carbon bonds (35). Unfortunately later work showed the molecule to be static (5). 

Pressure experiments have indeed found this competition. It is evident from the comparison of the pressure dependent ordered AF moment, and the position and intensity of Si-NMR satellites. While the former increases continuously with pressure, the sphtting which is proportional to the local 5f-moment is pressure independent, however, the split satellite intensity... 

NMR studies carried out on nuclei such as FI, and Si this does not really impose any limitation on their observation. Broader spectral lines can be reproduced by pulse teclmiques, provided that corrections are made for the RF-irradiation and probe responses but this requires carefiil calibration. Such corrections have been most extensively used for examining satellite transition spectra from quadnipolar nuclei [11]. 

Figure Bl.12.13. MAS NMR spectra from kyanite (a) at 17.55 T along with the complete simulation and the individual components, (b) simulation of centreband lineshapes of kyanite as a fiinction of applied magnetic field, and tire satellite transitions showing (c) the complete spiimmg sideband manifold and (d) an expansion of individual sidebands and their simulation.

Satellite transition MAS NMR provides an alternative method for detennining the interactions. The intensity envelope of the spimiing sidebands are dominated by site A2 (using the crystal structure nomenclature) which has the smallest Cq, resulting in the intensity for the transitions of this site being spread over the smallest... 

The H NMR spectrum of pyridazine shows two symmetrical quartets of an A2X2 or A2B2 type dependent on the solvent and concentration. The satellites have been used to obtain all coupling constants. Spectra of C-substituted pyridazines, methylthio- and methylsulfonyl-pyridazines, both as neutral molecules and as cations, N-1 and N-2 quater-nized species, pyridazinones, hydroxypyridazinones, A-oxides and 1,2-dioxides have been reviewed (b-73NMR88> and are summarized in Tables 6, 7 and 8. 

Aside from C-H coupling constants (often obtained from satellites in NMR spectra) not very much information is available on the NMR spectra of small heterocycles. A recent review (B-79MI50101) devotes only seven pages to the NMR spectra of all three- and four-membered heterocyclics. 

All have zero nuclear spin except (33.8% abundance) which has a nuclear spin quantum number this isotope finds much use in nmr spectroscopy both via direct observation of the Pt resonance and even more by the observation of Pt satellites . Thus, a given nucleus coupled to Pt will be split into a doublet symmetrically placed about the central unsplit resonance arising from those species containing any of the other 5 isotopes of Pt. The relative intensity of the three resonances will be (i X 33.8) 66.2 ( x 33.8), i.e. 1 4 1. 

The INADEQUATE experiment is a homonuclear NMR technique in which coupling satellites are detected after suppressing the stronger... 

The 2D INADEQUATE spectrum contains satellite-peaks representing direct coupling interactions between adjacent C nuclei. The 2D INADEQUATE spectrum and C-NMR data of methyl tetrahydrofuran are shown. Assign the carbon-carbon connectivities using the 2D INADEQUATE plot. 

The latter do not yield l,3-dichalcogen-2,4-phosphasilacyclobutanes if they are treated with excess elemental sulfur and tellurium. Compound 23a has been characterized by its 31P-NMR spectrum, which shows a singlet signal at 8 = -126.0, and by l25Te satellites with /(P,Te) = 222 Hz. The composition of 23b,c was proved by mass spectrometry and their... 

Vinyltin compounds are very important in organic synthesis, since the vinyl moiety can be readily transferred to carbon in the (palladium-catalyzed) Stille reaction. The transfer is stereospecific, and the geometry of the vinyltin moiety can be easily checked using proton and carbon-13 NMR via the coupling satellites. 

The 13C labels allow for use of 13C NMR in which the peaks containing the 13C label enrichment show satellites corresponding to a 1JCc coupling ( 30 Hz). The distribution pattern of 13C labels found was more complicated than one single pathway and pointed toward both pelletierine and cocaine-derived alkaloid pathways, both which incorporate two acetate units Hemscheidt T, Spenser ID (1993) J Am Chem Soc 115 3020... 

In 2006 Wimperis et al. proposed a method called satellite transitions acquired in real time by MAS (STARTMAS) [142, 202], which allows for the real-time acquisition of high-resolution NMR spectra of spin-3/2 nuclei under MAS. This method combines a train of pulses, similar to CPMG [109, 110], with sample rotation at the magic angle to refocus the quadrupolar broadening in a series of echoes, while allowing the isotropic quadrupolar shift and chemical shift to evolve. 

Fig. 9. (a) H, 15N] HSQC NMR spectra of 15N-labeled 7 and 2 mol equiv of 5 -GMP after lmin and 30 min of irradiation (, 195Pt satellites) (b) time dependent decrease in concentration of 7 and formation of 7rG and 7rG2 (lines drawn merely to connect points) (c) quantification of in vitro DNA repair synthesis using an extract prepared from the repair-proficient HeLa cell line. Cisplatin was taken as 100%. Adapted from Ref. (35). 

During the homogeneous hydrogenation of a variety of substrates - and in particular of those containing aryl groups - satellites appear in addition to the expected PHIP-NMR spectra of the usual para-hydrogenated products, typically shifted upfield relative to those of the authentic parent compounds [37]. 

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