Contents

Preface

Chapter 1 The Organic Set of NMR Spectra

Experiment 1.1 ¹H NMR Experiment

Experiment 1.2 ATP-¹³C NMR

Experiment 1.3 COSY

Experiment 1.4 NOESY

Experiment 1.5 HSQC

Experiment 1.6 HMBC

Chapter 2 Advanced Organic NMR Spectroscopy

Experiment 2.1 2D J-Resolved ¹H NMR Spectroscopy

Experiment 2.2 ROESY

Experiment 2.3 TOCSY

Experiment 2.4 HSQC-TOCSY

Experiment 2.5 HOESY

Experiment 2.6 INADEQUATE

Experiment 2.7 ADEQUATE

Experiment 2.8 J-HMBC

Experiment 2.9 Gated Decoupling

Chapter 3 Selective Methods

Experiment 3.1 Water Suppression by Presaturation

Experiment 3.2 Solvent Suppression by 1D-NOESY

Experiment 3.3 Water Suppression by SOGGY-Excitation Sculpting

Experiment 3.4 Solvent Suppression Using WET

Experiment 3.5 SELTOCSY

Experiment 3.6 SELNOESY

Experiment 3.7 SELINCOR

Experiment 3.8 SELINQUATE

Experiment 3.9 Band Selective HMBC

Chapter 4 Heteronuclear NMR

Experiment 4.1 ¹¹B NMR Spectroscopy

Experiment 4.2 ¹⁵N NMR Spectroscopy

Experiment 4.3 ¹⁷O NMR Spectroscopy

Experiment 4.4 ¹⁹F NMR Spectroscopy

Experiment 4.5 ²⁹Si NMR Spectroscopy

Experiment 4.6 ⁵⁷Fe NMR Spectroscopy

Experiment 4.7 ¹⁹⁵Pt NMR Spectroscopy

Chapter 5 Experiments in Physical Organic Chemistry

Experiment 5.1 Measurement of the Spin–Lattice Relaxation Time T₁

Experiment 5.2 Measurement of the Spin–Spin Relaxation Time T₂

Experiment 5.3 Dynamic ¹H NMR Spectroscopy

Experiment 5.4 Diffusion Measurement with DOSY

Experiment 5.5 Residual Dipolar Couplings (RDC)

Chapter 6 Organic Chemistry Applications

Experiment 6.1 ASIS

Experiment 6.2 Chirality Determination

Experiment 6.3 Advanced Mosher Method

Experiment 6.4 Quantitative NMR and Relaxation Reagents

Experiment 6.5 Determination of Association Constants Ka

Experiment 6.6 STD NMR

Experiment 6.7 A Kinetic Experiment

Chapter 7 An Excursion to the Solid State and to Structural Biology

Experiment 7.1 The CP/MAS Experiment

Experiment 7.2 High-Resolution Magic-Angle Spinning

Experiment 7.3 HN-HSQC

Experiment 7.4 HNCA

Chapter 8 Maintenance and Calibration

Experiment 8.1 Calibration of pulse Duration in the Transmitter Channel

Experiment 8.2 Calibration of the Pulse Duration in the Indirect Channel

Experiment 8.3 Shaped Pulses

Experiment 8.4 Adiabatic Pulses

Experiment 8.5 Temperature Calibration in NMR

Experiment 8.6 Calibration of Pulsed Field Gradients

Answer

Answers Chapter 1

Answers Chapter 2

Answers Chapter 3

Answers Chapter 4

Answers Chapter 5

Answers Chapter 6

Answers Chapter 7

Answers Chapter 8

Pulse Programs

Elementary Product Operator Formalism Rules

1. 90° Pulses

2. Chemical Shift

3. Spin–Spin Coupling

4. Shift Operators

5. Literature

Chemical Shift and Spin-Coupling Data for Strychnine

Picture Credits

Index

Related Titles

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Berger, Stefan/Braun, Siegmar

200 and More NMR Experiments

A Practical Course

ISBN: 978-3-527-31067-8

Authors

Matthias Findeisen

University of Leipzig

Dept. of Analytical Chemistry

Johannisallee 29

04103 Leipzig

Germany

Stefan Berger

Dept. of Analytical Chemistry

University of Leipzig

Johannisallee 29

04103 Leipzig

Germany

Cover

The cover shows Strychnos nux vomica, the tree from which semen strychnine, one of the model compounds used in many of the experiments in this book, is extracted. The picture was taken by the senior author in the botanical garden of Cape town. In addition, the 3D structure of strychnine and the HSQC pulse diagram to observe 2D (¹H,¹³C)-correlation NMR spectra is given.

All books published by Wiley-VCH are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate.

Library of Congress Card No.:

applied for

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

Bibliographic information published by the Deutsche Nationalbibliothek

The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at <http://dnb.d-nb.de>.

© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Boschstr. 12, 69469 Weinheim, Germany

All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.

Print ISBN: 978-3-527-33483-4

ePDF ISBN: 978-3-527-33696-8

ePub ISBN: 978-3-527-33694-4

Mobi ISBN: 978-3-527-33697-5

Preface

Many of our readers know the earlier books in this series, “100 and more Basic NMR Experiments” (1996), “150 and more Basic NMR Experiments” (1998) and “200 and more NMR Experiments” (2004). Since all books of this highly successful series have been sold out, we have asked ourselves whether it would be worthwhile to further increase the number of NMR experiments in a next edition. This could easily have been done, because NMR is still a very vivid field of science with a steady urge of innovation.

However, in daily discussions with our own co-workers we had to realize that even these people were not able to recall all or even the more important experiments from “200 and more”. Thus we finally decided on a “downsizing” and present in this volume “50 and more Essential NMR Experiments”, a much smaller collection. We feel that at least these should be known to the experimental NMR operator in a chemical environment. A severe cut concerns solid state NMR and NMR in structural biology, where we provide only 4 examples in this volume, knowing that especially these two fields of NMR are currently the most active ones. However, since this volume is mainly intended for organic and inorganic chemists we feel that this community is better served with a more targetted selection.

By implementing the experiments on your spectrometer, please keep in mind that some of the parameters are strongly machine dependent (e.g. power levels, spectral widths in Hz) and must be modified according to your situation. We reflect the values here as we used them to record the spectra pictured in the book.

Compared with the previous editions there are several changes to note.

(1) Dr. Matthias Findeisen, a physicist, replaces Siegmar Braun who retired several years ago.

(2) Nearly all experiments shown in this volume have been recorded anew, and the cited literature goes to mid 2012. There are a few entirely new experiments not present in the previous volumes. All experiments have been regrouped from a more chemical perspective.

(3) There is a new section Variants in which modifications of the actual experiments are mentioned.

(4) There is a new Question section at the end of each experiment. We hope that answering these questions will give the reader much more insight. Short answers are provided in the Appendix.

(5) The biggest change is certainly in the layout. Whereas our previous books were solid but rather dry scholarly textbooks, we have this time tried to compose a more modern book with accompanying graphics and photographs, with some historic text clips from celebrities of NMR and theire pictures. We hope that this change will help to raise interest, especially for the young people entering this fascinating field.

From the number of sold copies of our previous books we know that this information is at hand alongside numerous NMR spectrometers in the world, not counting the Chinese edition of “200 and more”. We certainly hope that the “50 Essentials” will be equally successful. We are fairly certain that every experiment works as described, but if not, please complain by email to

Prof. Dr. Stefan Berger

Institut für Analytische Chemie der Universität Leipzig

Linnéstr. 3, D-04103 Leipzig

e-mail: stberger@rz.uni-leipzig.de

Fax: + 49 341-9736115

Internet: http://www.uni-leipzig.de/~nmr/STB

Finally, we have to thank many colleagues for helpful discussions and in particular Mrs. U. Zeller, who provided all the layout ideas and who was responsible for getting all this together. In addition, we thank Dr. P. Tzetkova for recording the data of experiment 3.9 and Dipl. Biochem. A. Beil for recording the data of experiment 6.7.

Leipzig, April 2013

Matthias Findeisen

Stefan Berger

Quo innumerabiles libros et bibliothecas, quarum dominus vix tota vita indices perlegit? Onerat discentem turba, non instruit, multoque satius est paucis te auctoribus tradere quam errare per multos.

Lucius Annaeus Seneca (4 bc - 65 ad, De tranquillitate animi, IX, 4.)

What is the use of having countless books and libraries whose titles their owners can scarcely read through in a whole lifetime? The learner is not instructed but burdened by the mass of them, and it is much better to surrender yourself to a few authors than to wander through many.

Translated by J. W. Basore

Chapter 1

The Organic Set of NMR Spectra

There are six NMR spectral methods, which are usually first measured on a routine basis if an organic chemist has produced a new compound. Usually, this organic set is sufficient for a complete structural elucidation, especially if additional support comes from mass spectrometry and IR-or UV-spectroscopy.

These six methods are:

1.1 ¹H-NMR

1.2 APT-¹³C-NMR [Attached Proton Test]

1.3 COSY [COrelation SpectroscopY]

1.4 NOESY [Nuclear Overhauser Effect SpectroscopY]

1.5 HSQC [Heteronuclear Single Quantum Coherence]

1.6 HMBC [Heteronuclear Multiple Bond Correlation]

We describe therefore in this first chapter these six methods in some detail using strychnine as an example. Strychnine with its rather complicated molecular structure provides all the typical problems encountered during spectral assignments in organic chemistry. With concurrent instrumentation and about 20 mg of substance having a molecular weight around 500 Da, the total recording time of these techniques will be about 5 h.

Of course, this book offers much more, but this organic set comprises the most essential of all our essentials.

taken from TAMU NMR Letters, 1975, 199, 49.

Experiment 1.1 ¹H NMR Experiment

1. Purpose

The aim of the standard ¹H NMR experiment is to record a routine proton NMR spectrum in order to get structure-related information for the protons of the sample, i. e. chemical shifts, spin–spin couplings, and intensities. Here we apply this standard procedure to strychnine and discuss different weighting functions and problems of integration.

The prospect of measuring very rapid reaction rates by NMR provided the inspiration for getting an affirmative response from Linus Pauling [then chairman of the division of Chemistry and Chemical Engineering at California Institute of Technology] that “with NMR, we could investigate the borderline between resonance and tautomerism”. For example, investigating the NMR spectrum of cycloheptatriene with temperature to see if it existed as a rapidly equilibrating mixture of cycloheptatriene and norcaradiene, or was what later would be called a “monohomobenzene”. The argument was persuasive and we soon ordered a 30-MHz Varian proton and fluorine spectrometer.

J. D. Roberts, * 1918 “A Personal NMR Odyssey” Enyclopedia of NMR, 1996, 1, 590–598.

2. Variants

Variants of this form of NMR spectroscopy include first of all excitation with different pulse angles.

However, since recent NMR instruments are sensitive enough, usually one 90° scan is sufficient to obtain a spectrum. Therefore no considerations about reduced pulse angles are necessary. Second, if a strong solvent signal is present, different forms of signal suppression are available. These are discussed in chapter 3.

3. Pulse Scheme and Phase Cycle

Scheme 1.1-1

Common values:

p1: 90° ¹H transmitter pulse

d1: relaxation delay

4. Acquisition

Special values used for the spectrum shown:

Sample: 3% strychnine in CDCl₃.

Time requirement: 1 min

Spectrometer: Bruker DRX-600 with 5-mm-TBI-probe

td:

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