Magnetic resonance spectroscopy multinuclear studies

The overall physical principles and characteristics of magnetic resonance spectroscopy (MRS) are identical to those of MRI 942 Multinuclear MRS studies have demonstrated alterations in brain of... 

The synthesis of the complex is followed by the most important step of characterization of the complex. The composition and the structural features of both the ligand and complex have to be established before embarking on further studies. There exist many methods by which the composition and structural features of the complexes are studied. Some of the methods are (i) elemental analysis, (ii) X-ray crystallography, (iii) UV-Vis absorption spectra, (iv) infrared spectroscopy, (v) Raman spectroscopy, (vi) thermal methods of analysis such as thermogravimetry, differential thermal analysis, (vii) nuclear magnetic resonance spectroscopy (proton, multinuclear), (viii) electrospray mass spectrometry. Depending upon the complexity of the system, some or all the methods are used in the studies of complexes. 

The tautomerism in the solid state and in solution of five 4-bromo-1 //-pyrazoles has been studied by multinuclear magnetic resonance spectroscopy <07T8104>. When there is a bromine atom at position 3(5), the tautomer present in all cases in the solid state and in the solution state is the 3-bromo one. 

Bernd Wrackmeyer received his Diploma in Chemistry from the University of Munich in 1971 and his Ph.D. from the same University with Heinrich Noth in 1973. He performed postdoctoral studies at John Cass College of Science and Technology in London with William McFarlane in 1974 and moved back to the University of Munich in 1975, where he finished his habilitation in 1979. He became a Heisenberg-Fellow in 1983 and moved to the University of Bayreuth in 1986. His work focuses on the application of multinuclear magnetic resonance spectroscopy (NMR), on the chemistry of organoboranes, carboranes, Group 14 metal chemistry and on metal amides. 

R. Pires, T.G. Nunes, I. Abrahams, G.E. Hawkes, C.M. Morals, C. Fernandez, Stray-field imaging and multinuclear magnetic resonance spectroscopy studies on the setting of a commercial glass-ionomer cement, J. Mater. Sci. Mater. Med. 15 (2004) 201-208. 

Galajov M, Garcia C, Gomez M, Gomez-Sal P. Alkyl chlorido hydridotris(3,5-dimethylpyrazolyl)borate imido niobium and tantalum(V) complexes synthesis, conformational states of alkyl groups in soHd and solution. X-ray diffraction and multinuclear magnetic resonance spectroscopy studies. Dalton Trans. 2014 43 5747-5758. 

The structures of K-rieh feldspar, (K > Na)AlSi30g were studied by high-resolution MAS multinuclear magnetic resonance spectroscopies, leading to Si, Al and Na spectra at 9.4 T and Al, and Na spectra at... 

Basic principles of modem NMR spectroscopy are the subject of many textbooks [167,188-196], including pulse techniques [197] for NMR of polymers, see Bodor [198]. A guide to multinuclear magnetic resonance is also available [199]. Several texts deal specifically with multidimensional NMR spectroscopy [169,197,200-202]. Ernst et al. [169] have reviewed the study of dynamic processes, such as chemical exchange... 

Up to about the 1960 s, elemental analysis coupled with absorption spectra and infrared spectra and X-ray crystallography were the primary methods used in the studies of complexes. Later on with the developments in nuclear magnetic resonance (NMR) spectroscopy, especially multinuclear NMR, this technique has been invariably used in the studies of structural features of lanthanide complexes. To illustrate these points some references to literature are herein pointed out. The studies on the rare earth 1,3-diketonates, where 1,3-diketones are acetyl acetone, benzoyl acetone, dibenzoyl methane and 2-thienoyl tri-fluoroacetone totally relied on elemental analysis, UV-Vis and IR spectra to establish the nature of the complexes [89]. The important role played by X-ray crystallography in the elucidation of the structures of lanthanide complexes has been extensively discussed in Chapter 5 and the use of this technique goes as far back as the 1960 s. Nevertheless it continues to play a major role in the studies of lanthanide complexes. 

The radioactive nature of the actinides, especially the transuranics, can introduce significant challenges in the characterization of their complexes. In order to prevent contamination, multiple layers of containment are often required, which can limit the types of studies that can be undertaken. However, a suite of spectroscopic tools has been used to study the chemistry and speciation of the actinides. A partial list of these techniques includes absorption, emission and vibrational spectroscopies, X-ray absorption and diffraction, and multinuclear magnetic resonance. 

Organometalhc complexes of technetium-99 can be studied by the traditional physical tools used in chemistry. Techniques hke infrared, multinuclear magnetic resonance, and mass spectroscopies, as well as magnetic susceptibility (to determine the number of unpaired electrons and thus the oxidation state) and X-ray crystallography are the main methods to study these complexes. X-ray diffraction methods are particularly important since only one small crystal is needed to determine the complete structure of the compound. 

The spectroscopy of multinuclear magnetic resonance in solution is one of the most important analytical methods in structural studies of transition metal hydride complexes. Among different nuclei, the proton plays the main role because H NMR provides a direct information about spectral properties of the hydride ligands. In addition the proton, being a non-quadrupolar and long-relaxing nucleus, gives rise to well-resolved NMR spectra which are very... 

This review presents recent developments in the application of nuclear magnetic resonance (NMR) spectroscopy to study ionic liquids. In addition to routine structural characterization of synthesized ionic liquids, availability of multitude of advanced NMR techniques enables researchers to probe the structure and dynamics of these materials. Also most of the ionic liquids contain a host of NMR-active nuclei that are perfectly suitable for multinuclear NMR experiments. This review focuses on the application of NMR techniques, such as pulsed field gradient, relaxometry, nuclear Overhauser effect, electrophoretic NMR, and other novel experiments designed to investigate pure ionic liquids and the interaction of ionic liquids with various salts and solutes. 

Among the techniques more frequently used for elucidating cluster structures are crystallographic studies by both single-crystal X-ray and neutron-diffraction techniques, multinuclear high resolution nuclear magnetic resonance (NMR), and infrared spectroscopy. 

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