Ab Initio Calculations of Conformational Effects on 13C NMR Spectra of Amorphous Polymers

Ab Initio Calculations of Conformational Effects on 13C NMR Spectra of Amorphous Polymers PDF Author: R. Born
Publisher: Springer Science & Business Media
ISBN: 364260644X
Category : Technology & Engineering
Languages : en
Pages : 132

Get Book Here

Book Description
In NMR, it is well-known that the chemical shift conveys structural informa tion, e. g. a carbonyl carbon will have a resonance frequency appreciably dif ferent from a methyl carbon, etc. The relation between structure and chemical shift is mostly established by empirical rules on the basis of prior experience. It is only quite recently that the advent of both comparatively cheap comput ing power and novel quantum chemistry approaches have provided feasible routes to calculate the chemical shift at the ab initio level for molecules of reasonable size. This raises the question whether application of these novel theoretical concepts offers a means of obtaining new structural information for the complex chain molecules one deals with in polymer science. Solid state 13C-NMR spectra of glassy amorphous polymers display broad, partially structured resonance regions that reflect the underlying disorder of the polymer chains. The chemical shift responds to the variation of the ge ometry of the chain, and the broad resonance regions can be explained by an inhomogeneous superposition of various chain geometries (and thus chem ical shifts). In this review, we present a novel approach to combine polymer chain statistical models, quantum chemistry and solid state NMR to pro vide quantitative information about the local chain geometry in amorphous polymers. The statistical model yields the relative occurrence of the various geometries, and quantum chemistry (together with a force field geometry op timization) establishes the link between geometry and chemical shift.

Ab Initio Calculations of Conformational Effects on 13C NMR Spectra of Amorphous Polymers

Ab Initio Calculations of Conformational Effects on 13C NMR Spectra of Amorphous Polymers PDF Author: R. Born
Publisher: Springer Science & Business Media
ISBN: 364260644X
Category : Technology & Engineering
Languages : en
Pages : 132

Get Book Here

Book Description
In NMR, it is well-known that the chemical shift conveys structural informa tion, e. g. a carbonyl carbon will have a resonance frequency appreciably dif ferent from a methyl carbon, etc. The relation between structure and chemical shift is mostly established by empirical rules on the basis of prior experience. It is only quite recently that the advent of both comparatively cheap comput ing power and novel quantum chemistry approaches have provided feasible routes to calculate the chemical shift at the ab initio level for molecules of reasonable size. This raises the question whether application of these novel theoretical concepts offers a means of obtaining new structural information for the complex chain molecules one deals with in polymer science. Solid state 13C-NMR spectra of glassy amorphous polymers display broad, partially structured resonance regions that reflect the underlying disorder of the polymer chains. The chemical shift responds to the variation of the ge ometry of the chain, and the broad resonance regions can be explained by an inhomogeneous superposition of various chain geometries (and thus chem ical shifts). In this review, we present a novel approach to combine polymer chain statistical models, quantum chemistry and solid state NMR to pro vide quantitative information about the local chain geometry in amorphous polymers. The statistical model yields the relative occurrence of the various geometries, and quantum chemistry (together with a force field geometry op timization) establishes the link between geometry and chemical shift.

Solid State NMR Spectroscopy for Biopolymers

Solid State NMR Spectroscopy for Biopolymers PDF Author: Hazime Saitô
Publisher: Springer Science & Business Media
ISBN: 1402043031
Category : Science
Languages : en
Pages : 455

Get Book Here

Book Description
‘‘Biopolymers’’ are polymeric materials of biological origin, including globular, membrane, and fibrous proteins, polypeptides, nucleic acids, po- saccharides, lipids, etc. and their assembly, although preference to respe- ive subjects may be different among readers who are more interested in their biological significance or industrial and/or medical applications. Nevert- less, characterizing or revealing their secondary structure and dynamics may be an equally very important and useful issue for both kinds of readers. Special interest in revealing the 3D structure of globular proteins, nucleic acids, and peptides was aroused in relation to the currently active Structural Biology. X-ray crystallography and multidimensional solution NMR sp- troscopy have proved to be the standard and indispensable means for this purpose. There remain, however, several limitations to this end, if one intends to expand its scope further. This is because these approaches are not always straightforward to characterize fibrous or membrane proteins owing to extreme difficulty in crystallization in the former, and insufficient spectral resolution due to sparing solubility or increased effective molecular mass in the presence of surrounding lipid bilayers in the latter.

Annual Reports on NMR Spectroscopy

Annual Reports on NMR Spectroscopy PDF Author:
Publisher: Academic Press
ISBN: 0080584179
Category : Science
Languages : en
Pages : 363

Get Book Here

Book Description
NMR is used in all areas of modern science, and its applications continue to grow. In 1995 we celebrated the 50th anniversary of the discovery of NMR Spectroscopy and almost 30 years since the appearance of the firstvolume of Annual Reports on NMR Spectroscopy. During these years, a large and diverse collection of topics have been covered, and the contents of Volume 34 are no exception. This volume consists of six chapters covering a wide range of polymer science topics. Each chapter demonstrates the unique ability of NMR to provide information of both general and special interests.

Nuclear Magnetic Resonance

Nuclear Magnetic Resonance PDF Author: G A Webb
Publisher: Royal Society of Chemistry
ISBN: 1847553842
Category : Science
Languages : en
Pages : 657

Get Book Here

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.

Reviews in Computational Chemistry, Volume 17

Reviews in Computational Chemistry, Volume 17 PDF Author: Kenny B. Lipkowitz
Publisher: John Wiley & Sons
ISBN: 0471458813
Category : Science
Languages : en
Pages : 431

Get Book Here

Book Description
Computational chemistry is increasingly used in most areas of molecular science including organic, inorganic, medicinal, biological, physical, and analytical chemistry. Researchers in these fields who do molecular modelling need to understand and stay current with recent developments. This volume, like those prior to it, features chapters by experts in various fields of computational chemistry. Two chapters focus on molecular docking, one of which relates to drug discovery and cheminformatics and the other to proteomics. In addition, this volume contains tutorials on spin-orbit coupling and cellular automata modeling, as well as an extensive bibliography of computational chemistry books. FROM REVIEWS OF THE SERIES "Reviews in Computational Chemistry remains the most valuable reference to methods and techniques in computational chemistry."—JOURNAL OF MOLECULAR GRAPHICS AND MODELLING "One cannot generally do better than to try to find an appropriate article in the highly successful Reviews in Computational Chemistry. The basic philosophy of the editors seems to be to help the authors produce chapters that are complete, accurate, clear, and accessible to experimentalists (in particular) and other nonspecialists (in general)."—JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Quantum Chemistry

Quantum Chemistry PDF Author: Tamás Veszprémi
Publisher: Springer Science & Business Media
ISBN: 1461541891
Category : Science
Languages : en
Pages : 381

Get Book Here

Book Description
`Quantum Chemistry [the branch of Computational Chemistry that applies the laws of Quantum Mechanics to chemical systems] is one of the most dynamic fields of contemporary chemistry, providing a solid foundation for all of chemistry, and serving as the basis for practical, computational methodologies with applications in virtually all branches of chemistry ... The increased sophistication, accuracy and scope of the theory of chemistry are due to a large extent to the spectacular development of quantum chemistry, and in this book the authors have made a remarkable effort to provide a modern account of the field.' From the Foreword by Paul Mezey, University of Saskatchewan. Quantum Chemistry: Fundamentals to Applications develops quantum chemistry all the way from the fundamentals, found in Part I, through the applications that make up Part II. The applications include: molecular structure; spectroscopy; thermodynamics; chemical reactions; solvent effects; and excited state chemistry. The importance of this field is underscored by the fact that the 1998 Nobel Prize in Chemistry was awarded for the development of Quantum Chemistry.

NMR

NMR PDF Author: R. Born
Publisher:
ISBN:
Category : Amorphous substances
Languages : en
Pages : 142

Get Book Here

Book Description


Multidimensional Solid-state Nuclear Magnetic Resonance Spectroscopy of Pharmaceuticals and Polymers

Multidimensional Solid-state Nuclear Magnetic Resonance Spectroscopy of Pharmaceuticals and Polymers PDF Author: Mark Thomas Zell
Publisher:
ISBN:
Category :
Languages : en
Pages : 432

Get Book Here

Book Description


Modeling NMR Chemical Shifts

Modeling NMR Chemical Shifts PDF Author: Julio C. Facelli
Publisher:
ISBN:
Category : Medical
Languages : en
Pages : 392

Get Book Here

Book Description
This book reviews the history of NMR chemical shielding while surveying new developments in the field. Topics include new methods for calculating NMR chemical shifts, calculations of chemical shifts for important biological molecules, new theories about the role of chemical shifts, and modeling methods for chemical shifts in inorganic compounds.

Multidimensional Solid-State NMR and Polymers

Multidimensional Solid-State NMR and Polymers PDF Author: Klaus Schmidt-Rohr
Publisher: Elsevier
ISBN: 0080925626
Category : Science
Languages : en
Pages : 501

Get Book Here

Book Description
NMR spectroscopy is the most valuable and versatile analytical tool in chemistry. While excellent monographs exist on high-resolution NMR in liquids and solids, this is the first book to address multidimensional solid-state NMR. Multidimensional techniques enable researchers to obtain detailed information about the structure, dynamics, orientation, and phase separation of solids, which provides the basis of a better understanding of materials properties on the molecular level.Dramatic progress-much of it pioneered by the authors-has been achieved in this area, especially in synthetic polymers. Solid-state NMR now favorably competes with well-established techniques, such as light, x-ray, or neutron scattering, electron microscopy, and dielectric and mechanical relaxation.The application of multidimensional solid-state NMR inevitably involves use of concepts from different fields of science. This book also provides the first comprehensive treatment of both the new experimental techniques and the theoretical concepts needed in more complex data analysis. The text addresses spectroscopists and polymer scientists by treating the subject on different levels; descriptive, technical, and mathematical approaches are used when appropriate. It presents an overview of new developments with numerous experimental examples and illustrations, which will appeal to readers interested in both the information content as well as the potential of solid-state NMR. The book also contains many previously unpublished details that will be appreciated by those who want to perform the experiments. The techniques described are applicable not only to the study of synthetic polymers but to numerous problems in solid-state physics, chemistry, materials science, and biophysics. - Presents original theories and new perspectives on scattering techniques - Provides a systematic treatment of the whole subject - Gives readers access to previously unpublished material - Includes extensive illustrations