Structural Identification of Organic Compounds with
Spectroscopic Techniques. By Yong-Cheng Ning (Tsinghua
University). Wiley-VCH, Weinheim. 2005. xvi + 452 pp.
17.2 24.5 cm. ￡49.00. ISBN 3-527-31240-4.
As a teacher of courses on organic structure elucidation
at both undergraduate and graduate levels, I am always
interested to read new monographs on this subject and find
new examples, distinct approaches to the theoretical
explanation of organic spectroscopy techniques, and other
useful information that can help students gain experience
in organic structure analysis. Since the number of books
dealing with this subject is not small, interested readers
need to exercise caution in selecting a specific monograph
that covers a sufficient number of topics in adequate depth
and clarity, to avoid spending much time searching for
specific information from multiple sources. In this sense,
Professor Ning’s book is interesting from the theoretical
perspective.
The book is divided in three main topics: nuclear
magnetic resonance, mass spectrometry, and infrared
spectroscopy. Not surprisingly, four chapters (almost half
of the book) are devoted to NMR topics, including an
introductory chapter, followed by one chapter on 1H NMR,
one on 13C NMR, and the last on two-dimensional NMR
techniques. It was a pleasure to find an excellent theoretical
background in NMR physical phenomena, but without
an exaggerated amount of mathematical treatment. The
NMR theory presented in the book is more in depth than
I usually find, a positive quality of this monograph.
Although the text explanations are rather brief, its logical
style is easy to read and I believe that it could be very
helpful for students searching for NMR theory applied to
organic structure determination. This point is valid for the
presentation of 2D-NMR pulse sequences as well.
The same approach is used to demonstrate several ionization
techniques and ion analysis in mass spectrometry
in the first chapter of the MS section, while the second
chapter on MS is directed to the fragmentation of organic
compounds and interpretation of mass spectra. Infrared
and Raman spectroscopy is the subject of the last theoretical
chapter. I was impressed with a quantum-mechanical
explanation of infrared spectroscopy, a topic that I have
not seen included in other books on organic structure
determination.
To my surprise and disappointment, the practical approach
to organic structure determination was of much
inferior quality. In all the NMR spectra presented in the
book there is no indication of the field frequency and
solvent used to obtain the spectra. Some spectra are really
very much out-of-date, with poor resolution and signal
definition, e.g., the 1H NMR spectra of Figures 2.18 (p 67),
2.21 (p 78), and 2.22 (p 81). There are no spectral examples
to illustrate the concepts of chemical and magnetic equivalence,
coupling constants, magnetic anisotropy, field effects,
deuterium exchange, shift reagents, and homotopic, enantiotopic,
and diastereotopic hydrogens. Specific chapter
exercises are very limited in number. No exercises are
offered at the end of the chapters about 2D-NMR techniques,
mass spectrometry, and infrared spectroscopy. A
final chapter on structure determination is given, with an
introductory basic approach in solving structure determination.
Nevertheless, the logic in discussing spectral
interpretation is sometimes questionable. For example, in
exercise 1 of this chapter the reader must deduce by
himself/herself that the number of hydrogens was obtained
from the 1H NMR spectrum integration, which was not
normalized. In the same example, carbonyl signals in both
13C NMR and infrared spectra are superficially discussed
in order to provide an argument for the structure proposed.
The number of unsaturations deduced from the molecular
formula led to a monocyclic compound, a feature that is
barely explained. In example 2, the book provides a
molecular formula that accounts for an index of hydrogen
deficiency of 12, pointing to an “unknown compound with
a complex structure”. Rather than discussing the spectroscopic
data to establish the structure of the compound, it
is stated that “fortunately, there is only one natural product
in data bank of natural products” that accounts for the
collected data, and that structure is given. This is not a
didactic approach to demonstrate how a structure can be
Journal of Natural Products, 2005, Vol. 68, No. 10 1577
assembled from spectroscopic data. The subsequent examples
are not discussed in an appropriate manner either.
Consequently, the book suffers from a considerable weakness
in the practical sense of interpreting spectra.
I can recommend the book only for those interested in a
better understanding of the theoretical background of
organic spectroscopy.
Roberto G. S. Berlinck
Universidade de Sa?o Paulo
Sa?o Carlos, SP, Brazil
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发表于 2008-5-13 06:41:16
