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Book Review pH and Buffer Theory Ч A New Approach. (Series Solution Chemistry Vol. 1.) By H

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BOOKS
ed images, spectra can be compressed,
stretched, or edited in other ways, and so
on. By using the hypertext transfer protocol (HTTP), documents from any computer can be loaded onto the Internet, regardless of the operating system that they
use or the computer platform. The only
requirement for all these operations is that
the client browser’s plug-in is capable of
recognizing the standardized data structure of the application concerned.
The first Electronic Conference on
Trends in Organic Chemistry, ECTOC 1,
was organized by one of the pioneers in
the field of standardization of chemical
information, Henry S. Rzepa of Imperial
College, London, together with his colleague Christopher Leach, and Jonathan
M. Goodman (Department of Chemistry,
Cambridge University), and is published
in a CD-ROM version by the Royal Society of Chemistry.
The conference proceedings consist of
six “keynote papers” and 71 articles,
which present recent results (up to mid1995) in the areas of synthetic, mechanistic, and biological chemistry. The authors
are from 13 countries. On reading the
keynote papers one immediately appreciates the advantages of the HTML format.
A mouse-click on one of the two-dimensional valence bond formulas that are displayed brings up a three-dimensional image of the molecule that can be rotated at
will, an extremely useful facility for complicated structures. These 3D structures
are filed as Cartesian coordinates in the
format of the Brookhaven Protein Database (*.pdb files).
Taking as an example the contribution
“A New Synthetic Route to the Illudin
and Pterosin Family of Sesquiterpenes”,
by Albert Padwa, Erin A. Curtis, and Vincent P. Sandanayaka (Department of
Chemistry, Emory University, Atlanta),
the key structure can be viewed from any
direction and in many different representations (wire model, stick model, stickand-ball model, space-filling model, etc.) .
The coordinates (from an X-ray crystallographic analysis) on which this is based
are those of a precursor of illudin, which
already has all the five benzene ring substituents of the later products, with the
correct regiochemistry. Moreover, a novel
feature of the HTTP approach is that one
can then go on from this 3D presentation
to edit the data. Once the coordinates
from the X-ray data have been stored locally on the hard disk of one’s PC, the way
is clear for further data processing such as
energy calculations.
In the contribution “Studying Perturbation Theory with Explorer EyeChem
and VRML”, by Guillermo A. Suner,
1354
,G
Omer Casher, and Henry S. Rzepa, the
imaging of structures is taken a step further. These authors have translated the
semiempirical (AMI) calculated transition state structures for a large number of
Diels-Alder reactions into the VRML
format (virtual reality modeling language). This allows one to move around
in the virtual space of the calculated structures and study the overlapping of the
frontier orbitals. This technique opens up
new perspectives, in the truest sense of the
word, and has great possibilities for use in
teaching.
Most of the other contributions use
only HTML text and graphics in the GIF
format. They range over many different
areas of organic chemistry, from new syntheses of natural products and enantioselective catalytic reactions, via the chemistry of fullerenes (where, incidentally,
pdb coordinates would have been ideal),
to new nonlinear optical materials and to
purely theoretical studies. The work includes a full list of contributions to the
discussions of the individual presentations and a list of participants (with photographs in some cases), making altogether a very successful CD-ROM. Within the
next five years we may witness the disappearance of the conventional printed
“book of abstracts”.
Jorg Grunenberg
Institut fur Organische Chemie
der Technischen Universitat
Braunschweig (Germany)
pH and Buffer Theory - A New
Approach. (Series: Solution Chemistry, Vol. 1.) By H . Riibe. John Wiley
& Sons, Chichester, 1996. 192 pp.,
hardcover E 40.00.-ISBN
0-47196735-1
This subject has traditionally been a favorite area of research for Scandinavian
chemists, and H. Rilbe is on familiar
ground in this book. The author’s claim to
present a “new approach” refers essentially to a general procedure for treating all
types of problems in this field. According
to this, all the quantities that occur in pH
and buffer theory, such as concentrations
and equilibrium constants, are converted
into dimensionless logarithmic numbers,
so as to benefit from the well-known
mathematical simplifications associated
with the use of logarithmic relationships.
Despite this, however, as the arguments
are developed in greater depth the equations quickly become very complicated.
Consequently the author’s presentation
comes over as rather dry and leaden on
the whole, although that is partly due to
VCH Verlagsgesel1.schaftmbH, 0.69451 Weinheim, 1997
the nature of the subject. Another disadvantage of the author’s new approach is
that, because of the special expressions
that are used, one cannot simply begin
reading at a chosen place in a chapter or
section of interest; instead one must first
search back in the book to work out the
definitions. Many of the results have been
published before by the author in specialist journals, and thus the book is a summary and consolidation of that work.
Chapter 1 begins by introducing the
concepts of pH and the relevant equilibrium constants. For each of the aspects that
are treated from a stoichiometric standpoint the author then goes on to discuss
the thermodynamic relationships involved. Buffer solutions consisting of a
single-proton weak acid combined with a
strong base, or a weak base with a strong
acid, are considered next. Here the reader
meets the difficulty already mentioned
above, as one needs to be familiar with the
author’s definitions in order to fully understand the curves that are shown.
Chapter 2 deals with two-proton protolytes and their salts with strong acids
and bases. Here the ionic strength of
buffer solutions is also considered.
In Chapter 3 the author guides the
reader through the Scylla and Charybdis
of mixtures of weak acids and weak bases,
offering first an approximate solution to
the problem and then a more rigorous
analysis. Here, as in the other chapters, he
mentions alternative approaches used by
other authors and considers the strengths
and weaknesses of the different methods.
Chapter 4 treats acids with three or
more protons and their salts. Special attention is devoted to the differences between the K-values and how these affect
the buffer properties. The main topic of
Chapter 5 is the Debye-Huckel theory
for strong electrolytes and its application
to the calculation of activity coefficients.
Chapter 6 is entirely devoted to the buffer
properties of water and the associated
titration curves. This is followed by a
chapter on experimental methods for determining pK- and ApK-values and isoprotic (or isoelectric) points. Finally there
is an appendix containing some computer
programs for determining isoprotic
points.
This book, written by a well-recognized
expert in the field, is intended for the specialist rather than for the student, as indicated by the absence of exercise problems,
and not least by its price. It takes up from
the point where the usual introductions to
quantitative analysis leave off, and assumes that one is already familiar with
ordinary buffer theory. The question of
whether one can begin to accept the nota-
057o-0X3319713612-I354 $ 17.50+ .SO10
Angeu.. Cizrm. Inr. Ed. Engl. 1997, 36, N o 12
BOOKS
tion used in the book is for the reader to
decide. It remains to be seen to what extent the proposed new approach will be
taken up in research and teaching.
Bernhard Neumiiller
Fachbereich Chemie der Universitat
Marburg (Germany)
Introduction to Theoretical Organic
Chemistry and Molecular Modeling.
By W B. Smith. VCH Publishers,
New York, 1996. 192 pp., hardcover
DM 89.00.--ISBN 1-56081-937-5
Computer programs for quantumchemical calculations are becoming increasingly user-friendly, and consequently
chemists with limited theoretical knowledge are using them more and more often.
It is all too easy for non-theoreticians to
be misled by the suggestive power of the
attractive graphics. so that they overvalue
the information content of the results that
the black box turns out with so little effort. For these users there are only three
possible ways out of this dilemma: 1. leave
well alone; 2. work in collaboration with
colleagues; or 3. acquire the necessary
theoretical knowledge by private study.
This book by W. B. Smith is intended to
help with the third alternative.
It is certainly a welcome development
when an attempt IS made to present theoretical organic chemistry at such a level
that it can be understood by most nonspecialists. Although there are many excellent books on the quantum-mechanical
fundamentals of chemistry, few of these
offer help in the practical application of
theoretical methods. In accordance with
the title of this book, the author’s idea is
first to introduce the reader to the theoretical fundamentals of quantum chemistry
(qualitative MO theory), then in the second part (from Chapter 7 onward) to treat
the most commonly used theoretical
methods, and this approach is undoubtedly correct.
However, it must be said at the outset
that neither the first nor the second part is
suitable as a student textbook. The choice
of subject matter and the strong emphasis
placed on the Huckel theory give cause for
concern. It is true that in a treatment of
such a complex topic as this within a mere
Angebv. Clwn. hi.Ed EngI. 1997, 36, No. 12
192 pages, one has to be prepared to accept some compromises. Nevertheless, the
mathematical derivations must be errorfree, understandable, and entirely consistent. This book contains so many errors,
loose and careless statements, and lapses
from rigor in the physical arguments, that
a newcomer to the subject is at risk of
failing to follow the discussion o r getting
an incomplete picture. A few examples
will illustrate this. The first is the derivation of the Schrodinger equation in a few
steps on pages 2 and 3. The transition
from classical mechanics to quantum mechanics is made, without further explanation, by replacing the momentum in the
classical expression for the total energy by
the corresponding quantum-mechanical
operator, then multiplying the expression
by a wave function which appears from
nowhere. Arguments of this kind d o not
help towards an understanding of the
quantum theory. The symbols used for
variables are not always consistent. On
page 3 the symbol \i/ is used for the total
wave-function, whereas on page 4 it represents the basis orbitals. Later we find that
Y is used for molecular orbitals, whereas
in the description of the S C F methods (p.
109) Y represents the total wave-function
and \i/ a molecular orbital. As the text contains no mention of the changes in meaning, the reader unfamiliar with the theory
will inevitably be confused. In the mathematical formulas, vectors are never clearly
distinguished as such, and operators and
matrices only occasionally. The lack of
care in the text also appears in statements
that are difficult to understand or even
misleading. On page 30 alone we find that
a summation index is missing from each
of the equations (2.17) to (2.22), a bracket
is missing in the example of butadiene,
and in Equation (2.22) the indices on the
two sides of the equation d o not agree.
Often the symbols in the figures and equations d o not correspond to those in the
text; for example, on pages 32 and 33 the
coefficients are denoted by ‘a’ in the figure
but by a in the text, and on page 95 the
symbol for the basis orbitals is 4 in Equation (6.23) but cp in the text immediately
below. On page 119 the method described
here for minimizing the energy has little to
d o with the Newton-Raphson method to
which the author refers. Also the general
discussion about mathematical methods
C; VCH Verla~gesrllsrhafimbH, D-69451 Weinheim, 1997
for energy minimization is scarcely understandable and will convey little to the
reader. The explanation of CISD in
Section 7.4 is simply incorrect. “CI-singles,doubles” is not, as stated here, a linear combination of the ground state Slater
determinants and the first and second excited states.
There are also many mistakes in the
non-mathematical part of the book. In
Chapter 6 (pericyclic reactions, etc.) even
the first reaction equation (6.1) defining
pericyclic reactions is incorrect. In the
Claisen rearrangement shown here,
allylphenyl ether rearranges to give o-hydroxystyrene. In Equation (6.2) the second reaction arrow has below it nv instead
of hv, and hv is missing from Equation
(6.3). The claim that “. . . no stable ring
systems containing an odd number of
changes in fi can exist . . .” is presumably a guess. Again, it is incorrect
and misleading to state (on page 91) that
for a qualitative treatment of the stereochemistry of photochemical reactions it is
unimportant whether a singlet or a triplet
state is present. The list of errors and examples of slipshod writing could be continued.
The poor quality of the figures is evident even on first opening the book (the
Mobius strip on p. 88 and the energy hypersurface on p. 150 are two interesting
examples). Leaving aside esthetic considerations, many of the figures are not very
suitable for explaining the matters to
which they relate. For example, the connection between the orbital diagram
(6.20) and the reaction equation (6.18)
would only be apparent to a specialist.
Due to the large number of mistakes
and examples of careless writing, the absence of any indications as to the previous
knowledge assumed, and the disjointed
and unclear style in which the arguments
are presented, the reader unfamiliar with
the subject is unlikely to learn much from
the book. Moreover, the price seems unjustifiably high for a textbook of 192
pages. Perhaps the printing error on the
first page-“testbook”
in place of textbook-is
no ordinary mistake but a
Freudian slip.
Raiizer Herges
Institut fur Organische Chemie
der Technischen Universitlt
Braunschweig (Germany)
0570-0833/97/3612-13553 I7.50f .50;0
1355
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