31P and 13C NMR of Transition Metal Phosphine Complexes

31P and 13C NMR of Transition Metal Phosphine Complexes PDF Author: Paul S. Pregosin
Publisher: Springer Science & Business Media
ISBN: 3642488307
Category : Science
Languages : en
Pages : 164

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Book Description
For almost a quarter of a century the words "nuclear magnetic reso nance" were synonymous with proton I,leasurements. During this period the literature abounded with a seemingly infinite variety of 1H NHR studies concerned primarily with carbon chemistry. Occasionally a "novel" nucleus was studied and, even in those early days, the poten- 13 14 31 19 tial offered by C, N, P and F was clearly recognized. Despite the allure, the technical difficulties involved in measuring some of these nuclei were far from trivial. Small magnetic moments and low natural abundance in combination with spin-spin coupling from other nuclei, mostly protons, resulted in a signal-to-noise problem whose severity effectively excluded the study of metal complexes with unfa vorable solubility characteristics. The first important breakthrough came with the advent of broad band 1H-decoupling. For example, the featureless broad 31p resonance associated with the commonly used ligand triphenyl phosphine is converted to a sharp, more readily ob served singlet when wide-band decoupling is employed (see Fig. 1). Despite this improvement investigation of more interesting molecules, such as catalytically active complexes was forced to await the devel opment of Fourier Transform methods since only with relatively rapid signal averaging methods could sufficient signal-to-noise ratios be achieved.

31P and 13C NMR of Transition Metal Phosphine Complexes

31P and 13C NMR of Transition Metal Phosphine Complexes PDF Author: Paul S. Pregosin
Publisher: Springer Science & Business Media
ISBN: 3642488307
Category : Science
Languages : en
Pages : 164

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Book Description
For almost a quarter of a century the words "nuclear magnetic reso nance" were synonymous with proton I,leasurements. During this period the literature abounded with a seemingly infinite variety of 1H NHR studies concerned primarily with carbon chemistry. Occasionally a "novel" nucleus was studied and, even in those early days, the poten- 13 14 31 19 tial offered by C, N, P and F was clearly recognized. Despite the allure, the technical difficulties involved in measuring some of these nuclei were far from trivial. Small magnetic moments and low natural abundance in combination with spin-spin coupling from other nuclei, mostly protons, resulted in a signal-to-noise problem whose severity effectively excluded the study of metal complexes with unfa vorable solubility characteristics. The first important breakthrough came with the advent of broad band 1H-decoupling. For example, the featureless broad 31p resonance associated with the commonly used ligand triphenyl phosphine is converted to a sharp, more readily ob served singlet when wide-band decoupling is employed (see Fig. 1). Despite this improvement investigation of more interesting molecules, such as catalytically active complexes was forced to await the devel opment of Fourier Transform methods since only with relatively rapid signal averaging methods could sufficient signal-to-noise ratios be achieved.

NMR.

NMR. PDF Author:
Publisher:
ISBN:
Category : Nuclear magnetic resonance
Languages : en
Pages : 252

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Book Description


Oxygen-17 and Silicon-29

Oxygen-17 and Silicon-29 PDF Author:
Publisher: Springer Science & Business Media
ISBN: 3642877621
Category : Science
Languages : en
Pages : 242

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Book Description
Although it was shown very early [1] that the isotope 29Si is very valuable for NMR research, severe technical difficulties had to be overcome before silicon spectra could be recorded. This was due to the low sensitivity of the isotope resulting from its low gyro magnetic ratio, its low abundance and the rather long relaxation times. The introduction of the Fourier-Transform-Technique (FT-NMR) helped to surmount most of these problems, with the result, that more and more papers concerning silicon NMR appear. Thus, it seems now that most of the salient features of 29Si-NMR are known today. Some resume of the state of the art of 29Si_NMR have been reported [1-4]. Although the theory of 29Si-NMR is not yet understood beyond the basic features, it promises to be of value mainly for two reasons: 1. Silicon is strategically located in the Periodic Table of the elements between the elements carbon, aluminum and phosphorus. For an unified theory of chemical shifts and coupling constants of the heavier elements silicon NMR values will be important. 2. The normal coordination number of silicon is four. If the current view of the chemical shifts of the heavier elements is correct, then the paramagnetic part is dominant for the measured shift data. Two of the parameters used for the calcu lation of the paramagnetic part are bond orders and angles. Bond angles are rare ly determined experimentally with high precision.

Multinuclear NMR

Multinuclear NMR PDF Author: J. Mason
Publisher: Springer Science & Business Media
ISBN: 1461317835
Category : Science
Languages : en
Pages : 642

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Book Description
With the power and range of modern pulse spectrometers the compass of NMR spec troscopy is now very large for a single book-but we have undertaken this. Our book covers the Periodic Table as multinuclear spectrometers do, and introductory chapters are devoted to the essentials of the NMR experiment and its products. Primary products are chemical shifts (including anisotropies), spin-spin coupling constants, and relaxation times; the ultimate product is a knowledge of content and constitution, dynamic as well as static. Our province is chemical and biochemical rather than physical or technical; only passing reference is made to metallic solids or unstable species, or to practical NMR spectroscopy. Our aim is depth as well as breadth, to explain the fundamental processes, whether of nuclear magnetic shielding, spin-spin coupling, relaxation, or the multiple pulse sequences that have allowed the development of high-resolution studies of solids, multidimensional NMR spectroscopy, techniques for sensitivity enhancement, and so on. This book therefore combines the functions of advanced textbook and reference book. For reasonably comprehensive coverage in a single volume we have sum marized the information in tables and charts, and included all leading references.

Nuclear Magnetic Resonance Volume 9

Nuclear Magnetic Resonance Volume 9 PDF Author: Graham Alan Webb
Publisher: Royal Society of Chemistry
ISBN: 0851869602
Category : Nuclear Magnetic Resonance
Languages : en
Pages : 360

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Book Description
Annotation As a spectroscopic method, Nuclear Magnetic Resonance (NMR) has seen spectacular growth over the past two decades, both as a technique and in its applications. Today the applications of NMR span a wide range of scientific disciplines, from physics to biology to medicine. Each volume of Nuclear Magnetic Resonance comprises a combination of annual and biennial reports which together provide comprehensive of the literature on this topic. This Specialist Periodical Report reflects the growing volume of published work involving NMR techniques and applications, in particular NMR of natural macromolecules which is covered in two reports: "NMR of Proteins and Acids" and "NMR of Carbohydrates, Lipids and Membranes". For those wanting to become rapidly acquainted with specific areas of NMR, this title provides unrivalled scope of coverage. Seasoned practitioners of NMR will find this an in valuable source of current methods and applications. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading authorities in the relevant subject areas, the series creates a unique service for the active research chemist, with regular, in-depth accounts of progress in particular fields of chemistry. Subject coverage within different volumes of a given title is similar and publication is on an annual or biennial basis.

Nuclear Magnetic Resonance

Nuclear Magnetic Resonance PDF Author: G A Webb
Publisher: Royal Society of Chemistry
ISBN: 1847553656
Category : Science
Languages : en
Pages : 360

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Book Description
As a spectroscopic method, Nuclear Magnetic Resonance (NMR) has seen spectacular growth over the past two decades, both as a technique and in its applications. Today the applications of NMR span a wide range of scientific disciplines, from physics to biology to medicine. Each volume of Nuclear Magnetic Resonance comprises a combination of annual and biennial reports which together provide comprehensive of the literature on this topic. This Specialist Periodical Report reflects the growing volume of published work involving NMR techniques and applications, in particular NMR of natural macromolecules which is covered in two reports: "NMR of Proteins and Acids" and "NMR of Carbohydrates, Lipids and Membranes". For those wanting to become rapidly acquainted with specific areas of NMR, this title provides unrivalled scope of coverage. Seasoned practitioners of NMR will find this an in valuable source of current methods and applications. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading authorities in the relevant subject areas, the series creates a unique service for the active research chemist, with regular, in-depth accounts of progress in particular fields of chemistry. Subject coverage within different volumes of a given title is similar and publication is on an annual or biennial basis.

Organophosphorus Chemistry

Organophosphorus Chemistry PDF Author: Viktor Iaroshenko
Publisher: John Wiley & Sons
ISBN: 3527672257
Category : Science
Languages : en
Pages : 590

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Book Description
Filling the gap for an up-to-date reference that presents the field of organophosphorus chemistry in a comprehensive and clearly structured way, this one-stop source covers the chemistry, properties, and applications from life science and medicine. Divided into two parts, the first presents the chemistry of various phosphorus-containing compounds and their synthesis, including ylides, acids, and heterocycles. The second part then goes on to look at applications in life science and bioorganic chemistry. Last but not least, such important practical aspects as 31P-NMR and protecting strategies for these compounds are presented. For organic, bioinorganic, and medicinal chemists, as well as those working on organometallics, and for materials scientists. The book, a contributed work, features a team of renowned scientists from around the world whose expertise spans the many aspects of modern organophosphorus chemistry.

NMR and Chemistry

NMR and Chemistry PDF Author: J.W. Akitt
Publisher: CRC Press
ISBN: 148226837X
Category : Science
Languages : en
Pages : 400

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Book Description
Keeping mathematics to a minimum, this book introduces nuclear properties, nuclear screening, chemical shift, spin-spin coupling, and relaxation. It is one of the few books that provides the student with the physical background to NMR spectroscopy from the point of view of the whole of the periodic table rather than concentrating on the narrow applications of 1H and 13C NMR spectroscopy. Aids to structure determination, such as decoupling, the nuclear Overhauser effect, INEPT, DEPT, and special editing, and two dimensional NMR spectroscopy are discussed in detail with examples, including the complete assignment of the 1H and 13C NMR spectra of D-amygdain. The authors examine the requirements of a modern spectrometer and the effects of pulses and discuss the effects of dynamic processes as a function of temperature or pressure on NMR spectra. The book concludes with chapters on some of the applications of NMR spectroscopy to medical and non-medical imaging techniques and solid state chemistry of both I = F1/2 and I > F1/2 nuclei. Examples and problems, mainly from the recent inorganic/organometallic chemistry literature support the text throughout. Brief answers to all the problems are provided in the text with full answers at the end of the book.

Ni Organonickel Compounds

Ni Organonickel Compounds PDF Author: Peter W. Jolly
Publisher: Springer Science & Business Media
ISBN: 3662075334
Category : Science
Languages : en
Pages : 394

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Book Description
This volume starts the updating of the information on organonickel chemistry, one of the most active areas of modern organometallic chemistry. It covers all mononuclear compounds containing one nickel-to-carbon bond. The main part is devoted to the family of planar NiII compounds, RNi(D)2X, which within 20 years has increased from about 250 to more than 1000 members. This research interest has been stimulated by the fact that many compounds insert various unsaturated species into the Ni-C bond to create new organonickel species. Moreover, these compounds are important as intermediates in many catalytic processes involving organic halides. Compounds containing h*2-bonded heteroalkene molecules including the C1 fragments CO2 and CS2, and related metallocyclic compounds are also emphasized in this volume. These types of compounds play an important role in a number of nickel-catalyzed co-oligomerization reactions involving unsaturated organic compounds. Most of the compounds are well-characterized by modern spectroscopic techniques. The various types of compounds are in most cases confirmed by X-ray diffraction. The author of these volumes, a member of the M lheim group, has made many contributions of his own and is eminently qualified to critically review this area of research.

Comprehensive Coordination Chemistry II

Comprehensive Coordination Chemistry II PDF Author: J. A. McCleverty
Publisher: Newnes
ISBN: 0080913164
Category : Science
Languages : en
Pages : 11845

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Book Description
Comprehensive Coordination Chemistry II (CCC II) is the sequel to what has become a classic in the field, Comprehensive Coordination Chemistry, published in 1987. CCC II builds on the first and surveys new developments authoritatively in over 200 newly comissioned chapters, with an emphasis on current trends in biology, materials science and other areas of contemporary scientific interest.