Addition of paramagnetic ions

Lauterbur PC, Mendoni a-Dias HM, Rudin AM (1978) Augmentation of tissue water proton spin-lattice relaxation by in vivo addition of paramagnetic ions. In Dutton PL, Leigh JS, Scarpa A (eds) Frontiers of Biological Energetics, vol 1. Academic, New York, pp... 

Intractable n.m.r. spectra can sometimes be resolved by the addition of paramagnetic ions if the compound forms a complex with the ions. Eu and Pr " are particularly usefUl they shift the signals in opposite directions. The method can be us in aqueous solution, where shift reagents are not applicable. With the wide availability of high-field n.m.r. instruments, this method has become less useful than it was some ten years ago but, if two... 

Angyal was also one of the first who smdied the complexes of calcium with carbohydrates in the solution by means of NMR. He noticed that addition of paramagnetic ions like europinm and praseodium shifts the signals to a greater extend, so that better analysis can be performed [38-40]. 

The addition of paramagnetic species, such as the metal ions Cu ", Mn, or CF", can have dramatic effects on both the observed spectmm and the relaxation behavior of a molecule. The added ion reduces nuclear relaxation times, and permitting more rapid data collection. In addition, faster relaxation rates minimize NOE effects in the spectra, which can be useful in obtaining quantitative intensity data. The most widely used reagent for this purpose is chromium acetylacetonate [13681 -82-8] known as Cr(acac)2. Practically speaking, the use of such reagents requires care, because at... 

In a fourth experiment, a paramagnetic probe can be used to determine the proximity from the ATP-binding site of non-competitive inhibitors. An MnATP probe is generated by the addition of Mn ions to ATP [51]. The... 

Frozen rain and frost collected at a site close to a heavy traffic road as well as ground and river water were irradiated by y-rays at 77K. Signals of SO and N032 were observed121 in addition to paramagnetic ions such as Fe3+ and Mn2+. The reaction when OH radicals are annealed out is structure sensitive. 

Third, addition of paramagnetic Mn3+ ions into the B sites initiates A-B coupling of sufficient magnitude that N el ordering occurs in the... 

Flavin semiquinones in solution, being typical n radicals, ordinarily saturate very easily with microwave power. The center of the spectrum saturates more easily than do the outer wings [139,140,145]. Exceptions have been found where other paramagnetic species are in the vicinity of the semiquinone. Addition of paramagnetic metal ions to solutions containing flavin semiquinones can greatly decrease the saturability of the radical because of dipolar interactions with the metal ions [146], Similar behavior has been encountered in enzyme systems (below). 

PH Decoupling of trialkyl phosphites and phosphates by paramagnetic reagents only occurs when there is direct co-ordination. In most cases 8p is shifted downfield, but h showed no definite trend. The most effective reagent was cobalt chloride in acetonitrile solution. The H-1 proton of dinucleotide mono- and di-phosphates was identified by the broadening of its resonance that occurred upon the addition of Mn + ions. A study of the effects of paramagnetic ions on adenosine 5 -monophosphate has also been reported. ... 

Addition of paramagnetic metal ions, such as ions, to a... 

From the Raman spectra, it can be seen that the stretching vibration frequency of the MnOg bond decreases after Gd + doping since the atomic mass of the Gd + ion is higher than that of Mn3+ ions. The electron paramagnetic resonance spectrum shows a narrow signal centered at = 2.0. The spinel structure of is not disturbed by a minor addition of Gd ions, which occupy fhe 16d octahedral site of the crystal lattice. 

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