Basic Principles of NMR Spectroscopy

Before describing the application of Nuclear magnetic resonance (NMR) spectroscopy to potentized homeopathic drugs we would first discuss the basic principles of NMR spectroscopy. This spectroscopy is a powerful tool providing structural information about molecules. Like UV-visible and infra red spectrometry, NMR spectrometry is also a form of absorption spectrometry. Nuclei of some isotopes possess a mechanical spin and the total angular momentum depends on the nuclear spin, or spin number 1. The numerical value of I is related to the mass number and the atomic number and may be 0, Vi, 1 etc. The medium of homeopathic... 

The aim of this text is to introduce the fascinating topic of the hyphenation of chromatographic separation techniques with nuclear magnetic resonance spectroscopy to an interested readership with a background either in organic, pharmaceutical or medical chemistry. The basic principles of NMR spectroscopy, as well as those of separation science, should previously be known to the reader. 

This article provides a description of the basic principles of NMR spectroscopy. The many applications of this technique, which make it indispensable as a tool for the analytical chemist, are described in subsequent articles, which also include discussion of advanced techniques such as the NMR of solids, multidimensional NMR, and MRI. 

Basic Principles of nmr-Spectroscopy of Oriented Molecules The Spin Hamiltonian... 

The basic principles of absorption spectroscopy are summarised below. These are most obviously applicable to UV and IR spectroscopy and are simply extended to cover NMR spectroscopy. Mass Spectrometry is somewhat different and is not a type of absorption spectroscopy. 

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... 

Basic principles of MRS. The overall physical principles and characteristics of magnetic resonance spectroscopy (MRS) are identical to those described previously in the MRI section. In fact, magnetic resonance spectroscopy can simply be thought of as just another way of expressing the NMR signals that are recorded during an NMR experiment. Whether it is an MRI or and MRS experiment, virtually all of the same equipment is used and all of the basic NMR principles still apply. The prime difference that separates basic MRS from modern-day MRI is that in MRS, the... 

I assume that you are conversant with basic principles of XH or proton NMR spectroscopy as applied to small molecules. In particular, I assume that you understand the concepts of chemical shift (8) and spin-spin coupling, classical continuous-wave methods of obtaining NMR spectra, and decoupling experiments to determine pairs of coupled nuclei. If these ideas are unfamiliar to you, you may wish to review NMR spectroscopy in an introductory organic chemistry textbook before reading further. 

This book does not follow a chronological sequence but rather builds up in a hierarchy of complexity. Some basic principles of 51V NMR spectroscopy are discussed this is followed by a description of the self-condensation reactions of vanadate itself. The reactions with simple monodentate ligands are then described, and this proceeds to more complicated systems such as diols, -hydroxy acids, amino acids, peptides, and so on. Aspects of this sequence are later revisited but with interest now directed toward the influence of ligand electronic properties on coordination and reactivity. The influences of ligands, particularly those of hydrogen peroxide and hydroxyl amine, on heteroligand reactivity are compared and contrasted. There is a brief discussion of the vanadium-dependent haloperoxidases and model systems. There is also some discussion of vanadium in the environment and of some technological applications. Because vanadium pollution is inextricably linked to vanadium(V) chemistry, some discussion of vanadium as a pollutant is provided. This book provides only a very brief discussion of vanadium oxidation states other than V(V) and also does not discuss vanadium redox activity, except in a peripheral manner where required. It does, however, briefly cover the catalytic reactions of peroxovanadates and haloperoxidases model compounds. 

Spectroscopy has become a powerful tool for the determination of polymer structures. The major part of the book is devoted to techniques that are the most frequently used for analysis of rubbery materials, i.e., various methods of nuclear magnetic resonance (NMR) and optical spectroscopy. One chapter is devoted to (multi) hyphenated thermograviometric analysis (TGA) techniques, i.e., TGA combined with Fourier transform infrared spectroscopy (FT-IR), mass spectroscopy, gas chromatography, differential scanning calorimetry and differential thermal analysis. There are already many excellent textbooks on the basic principles of these methods. Therefore, the main objective of the present book is to discuss a wide range of applications of the spectroscopic techniques for the analysis of rubbery materials. The contents of this book are of interest to chemists, physicists, material scientists and technologists who seek a better understanding of rubbery materials. 

For detailed explanations of the basic principles of the NMR method, reference should be made to one of the established introductory texts (for example, [1-4]). From these, the reader will soon discover that the study of small molecules in solution by NMR spectroscopy has provided a wealth of structural and dynamic chemical information. However, the... 

P. J. Lukavsky, Basic Principles of RNA NMR Spectroscopy. In Structure and Biophysics - New Technologies for Current Challenges in Biology and Beyond J. D. Puglisi, Ed. Heidelberg Springer 2007 pp 65-80. 

Below, the basic principles of the QEC effect observed in NMR spectroscopy are outlined. Sufficient conditions are specified under which the spin-space Hamiltonian of a set of N-like nuclei in a molecule can be converted into an effective NMR Hamiltonian. The reasoning that follows is a reproduction of long-known ideas, which, however, are sometimes misinterpreted. It is essentially an adaptation of the pertinent formalism... 

Besides infrared spectroscopy the most convenient method for deducing the molecular structure is nuclear magnetic resonance spectroscopy (nmr). The basic principle of this method is the detection of changes in the orientation of the atomic nuclear spin of hydrogen (the spin of a proton) and carbon (the spin of the nucleus of the isotope). 

The basic principles of FT-NMR spectroscopy can be qualitatively explained as follows. Take, for example, an NMR spectmm that contains a single peak at a given frequency. The graph of this spectmm (Fig. 8.8) is a plot of intensity versus frequency. The same information can be conveyed by a plot of intensity versus time that shows a cosine wave at the frequency described by the graph of the usual NMR spectmm. This is shown in Figure 8.9, and for a spectmm with a single frequency, this plot of intensity versus time is almost as easy to interpret as the usual NMR spectmm shown in Figure 8.8. 

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