Book Review Fundamentals of Nuclear Magnetic Resonance. By J. W. Hennel and J. Kilnowskiкод для вставкиСкачать
The literature coverage now extends to mid-1990, while at the same time some outdated references have been dropped. There are 1700 new literature citations, bringing the total to over 3600. now listed (unlike the earlier editions) in alphabetical order. The subject index too is a valuable aid when working with this book. Goldberg‘s book on the same subject is based on one originally published in Russian in 1989. which has been revised and updated for this English version. It contains about 1300 literature references extending up to 1991. The subject index. which is mainly substance-orientated, is a useful working aid. The book by Dehmlow and Dehmlow begins with two chapters of more than 60 pages altogether on the theoretical basis of PTC. The first chapter is mainly concerned with the principles underlying the effectiveness of the most important types of catalysts, while the second deals with the mechanistic aspects of the different variants of the PTC method. Chapter 3 (over 300 pages long) is concerned with synthetic applications of PTC. It begins with a section on the choice of reaction conditions, such as the type and quantity of catalyst, the solvent, and the stirring rate. Particular attention is given to enantioselective PTC, describing its applications, problems. and the many potential sources of error. Next the authors describe various practical applications of PTC, arranged so far as possible according to reaction types. These include substitutions leading to alkyl halides, nitriles, esters, thiols. sulfides. and ethers. N - and C-alkylations, alkylations and acylations of ambidentate anions, isomerizations, H / D exchange reactions. and additions at C = O and C = N bonds. Also treated in detail are r-, p-, and y-elimination reactions, the preparation of phosphonium and sulfonium ylides. nucleophilic aromatic substitutions, applications of PTC to organometallic compounds. and reducrims and oxidations. I t is pleasing to find that as well as giving well-proven synthetic recipes the authors include general principles that have been derived for carrying out various types of transformations under phase transfer conditions. The large amount of factual information is very clearly presented. often in the form of tables. enabling the reader not only to quickly find specific details but also to get an overview of a chosen area. Goldberg’s book differs considerably from that of Dehmlow and Dehmlow. both in emphasis and in structure. A first chapter (24 pp.) dealing with the theoretical fundamentals is followed by several chapters describing some selected areas of application of PTC. Chapter 2. the longest in the book with about 100 pages. is concerned with PTC in the chemistry of N-heterocycles. Alkylations and acylations of compounds of this class are described, as also arc reactions of halogenated N-heterocycles with nucleophiles. Reactions of N-heterocycles with carbenes are treated next, followed by oxidations and reductions, as well as the use of PTC in the preparation of such compounds. In Chapter 3 (about 50 pp.). on PTC in organometallic chemistry, much attention is devoted to reactions iiivolving organosjlicon compounds; other reactions discussed include those of mercury. molybdenum, tungsten, iron, cobalt, and platinum compounds. Chapter 4 (about 70 pp.) is devoted to catalysis by metal complexes under phase transfer conditions, including reductions, oxidations. dehydrogenations, and carbonylations. Chapter 5. on three-phase catalytic reactions (about 30 pp.), discusses the advantages and disadvantages of using quaternary onium salts. crown ethers. or open-chain polyethers immobilized on polymers or other substrates for a variety of reactions. In Chapter 6. on asyminetric phase transfer catalysis (about 50 pp.), Goldberg discusses in great detail a number of types of reactions for which PTC has proved more or less successful. He also analyzes a number of experiments that failed completely and were thus of no interest for synthetic purposes, and identifies the factors that previously led to wrong interpretations. These latter discussions are extremely valuable for any chemist intending to apply PTC to asymmetric syntheses for the first time. However. reactions giving optical purities of 15-19% should not be regarded as satisfactory, as is implied on page 299. Chapter 7 (about 40 pp.) is concerned with less common variants of PTC; here the author discusses cationic reactions, reactions at phase boundaries between neutral species. inverse PTC, electron phase transfer, and reactions under the influence of ultrasonic excitation at phase boundaries. The book by Dehmlow and Dehmlow is a standard work on PTC. affording the reader a comprehensive overview ranging from the theoretical fundamentals to the diverse wealth of practical applications of this useful method in synthetic chemistry. It is an indispensable monograph for every chemist. being suitable not only for organic chemists with experience of PTC but also for those about to use this method of synthesis for the first time. Goldberg’s book does not give such a comprehensive picture. nor was that the author’s aim. Instead it is intended for specialists. Because of this quite different approach it may be regarded as complementary to the Dehmlow and Dehmlow monograph. extending the subject and treating it in greater depth, with detailed discussions of many applications of PTC. At some points one might say that it gives too much information-for example, the details given beside the reaction arrows of the synthesis schemes. In both books the subject matter is clearly arranged, in a readable style, and in a sturdy binding. No library should be without them. Fritz Theil Institut fur Angewandte Chemie Berlin-Adlershof (FRG) Fundamentals of Nuclear Magnetic Resonance. By J. W Hennel and J. Klinowski. Longman, Harlow (UK), 1993. 288 pp., paperback f 22.50.ISBN 0-582-06703-0 In their preface the authors formulate their aim: it is to explain the physical and mathematical basis of NMR sinTp/y but exactly. In a certain sense they succeed. However, the question is: what m e the fundamentals of nuclear magnetic resonance? In the opinion of the authors they are the magnetic dipole moment (of a compass needle, a current loop. an orbiting electron, or a nucleus with a spin), the magnetization of a macroscopic sample in thermodynamic equilibrium. the Larmor precession of an isolated spin, Bloch’s equations, the Fourier transformation, the Zeeman and dipolar parts of the Hamiltonian. the method of (second) moments, and the spin-echo and COSY experiments. Sure, all these topics are fundamentals of NMR. and I would regard it as almost a moral obligation of all those who practise N M R to be thoroughly familiar with fundamentals of this kind. It may well be the experience of Jacek Hennel and Jacek Klinowski that only too many are not. And I must admit that the authors’ overview and judgement are very likely quite correct. Therefore, let us admit that there is a need to explain such fundamentals simply and exactly. Does the book fulfill the promise? It starts with a chapter of 42 pages on the “Elements of Quantum Mechanics”. It is supplemented by five appendices explaining topics from “Complex Numbers” to “Sinusoidal Operators.” This is now the third recent book on N M R which I have read in which the authors assume, on the one hand, that they must provide an introduction to complex numbers and. BOOKS on the other. that their readers should master quantum mechanics up to the (spin) density matrix, the Hilbert space and the like. In my opinion it is a complete illusion to hope that someone who needs an introduction to complex numbers is able to appreciate any exposition of quantum mechanics. I am afraid, therefore, that Hennel’s and Klinowski’s book is of little help to those who have not previously followed a course in quantum mechanics. For those who have done so (and have worked through their homework problems) the book may be a useful revision. and they may like to see how quantum mechanics is applied cwx-tly and simply and at great length to practical cases. However, a major problem is that the book does not lead the reader far enough. Almost all the fundamentals remain on an educational, a cultural level. They d o not open the door to practical modern N M R . On the whole the book breathes the air of the fifties. maybe sixties. Pake’s ingenious but hopelessly obsolete “high frequency bridge“ is described to illustrate how N M R is detected. Pulse and F T N M R are discussed but no modern probehead or related instrumentation is shown. Of the total of 54 references no less than 37 appeared in o r before 1967. and 19 of these are from the fifties. All those from after 1980 are monographs and textbooks. Abragani appears under 1983, whereas I bought my copy of his book in 1961. The final chapter is on “Nuclear Magnetic Relaxation”. It brought me an almost nostalgic re-encounter with Gierer and Wirtz (1953) and their microviscosity coefficients. I had hoped for a more up-todate climax. I recommend the book for introductory N M R teaching. either in a class or in a laboratory course, and to all those who d o practical N M R work and desperately feel that they d o not really understand the fundamentals of their experimental tool. But they should not expect a link between these fundamentals and their own work. U. Hueherlen Max-Planck-Institut fur medizinische Forschung Heidelberg (FRG) Neural Networks for Chemists. An Introduction. By J. Zupan and J. Gasteiger. VCH Verlagsgesellschaft, Weinheim/VCH Publishers, New York, 1993. 305 pp., hardcover DM 138.00, paperback DM 68.00. -ISBN 3-527-28592-X/1-56081791-7 (hardcover), 3-527-28603-91 1-56081-793-3 (paperback) To explain precisely the basic concepts of a new interdisciplinary area of research and communicate them to a wide readership is a difficult task. Jure Zapan and Johann Gasteiger have managed to d o this very successfully. This book offers a sound introduction to artificial neural networks, with insights into their architecture, functioning, and applications, which is intended not only for chemists but also for scientists from other disciplines. The capabilities and limitations of different systems are compared and evaluated. The authors have sensibly limited their treatment to a few carefully chosen and clearly distinguished types of networks, explaining how they are used for classifying, modeling, and analyzing molecules and their properties, for evaluating visual images (e.g.. to interpret spectra o r to analyze structure-activity relationships), and for controlling chemical reactions. The book is written in a readable style and is well structured. The reader’s task is made easier by providing a short summary of the main learning objectives at the start of each chapter, and by the use of easily remembered mnemonics. The treatment is divided into two parts, one concerned with theory and the other with describing different types of applications. This arrangement means that, after studying the clear and very informative introduction to the topic, the reader can look at the examples of applications and assess the suitability of the chosen method in each case, possibly even suggesting an alternative solution. The chapters on Kohonen networks and counterpropagation systems are especially good. The examples of applications, such as the representation of the three-dimensional electrostatic potential of a molecule in the form of a two-dimensional map using the Kohonen approach, surprise one at first by the simplicity of the concepts, but this is in itself an illustration of one of the strengths of artificial neural networks. The authors explain clearly and concisely how these principles can be applied in order to make an appropriate selection of representative data for an analysis using neural networks. The reader is not distracted from the core issues by too many literature references in the text; instead the authors give a useful selection at the end of each chapter. In OUJ view there are only a few aspects of neural networks that have not been fully covered in the book. The authors have not discussed effective algorithms for the systematic optimization of network architectures --for example, genetic algorithms. Also, in restricting the discussion to the back-propagation algorithm for multipositional networks the authors have covered only a part (admittedly by far the largest) of the range of reliable strategies for supervised learning. A similar criticism applies to the choice of applications. In particular. the analysis of biological macromolecules receives only marginal treatment, being limited to predicting the three-dimensional structures of proteins from their amino acid sequences. Here it would have been desirable to include some more examples -e.g., the use ofneural networks to analyze data banks- -as these methods have already advanced considerably and much effort is being put into further developments. However. additional topics such as these can no doubt be included in a second edition. This is a very well-written guide for anyone who wants to make greater use of information theories in chemistry. The excellent quality of the contents and the presentation should ensure that it reaches a wide international readership. Gisbert Schneidu. Paul Wrerle Institut fur Medizinischel Technische Physik und Lasermedizin der Freien Universitiit Berlin (FRG) Homogeneous Transition Metal Catalyzed Reactions. Edited by W R. Moser and D.W Slocum. (Series: Advances in Chemistry, Vol. 230.) American Chemical Society, Washington, DC, 1992. 625 pp., hardcover $! 139.95.-ISBN 0-8412-2007-7 This book contains a substantial number of the presentations from the symposium on “New Science in Homogeneous Transition Metal Catalyzed Reactions”, held during the 199th National Meeting of the American Chemical Society, in Boston, Massachusetts, April 22-27, 1990. About one third of the chapters have been written by chemists working in industrial laboratories. The authors are in general very well known for their contributions to the field. The fact that the papers are subjected to the editorial standards of the ACS is a further warranty for the high quality of the book.