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Book Review Chemical Generation and Reception of Radio- and Microwaves. By A. L. Buchachenko and E. L. Frankevitch

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BOOKS
describing the Cope rearrangement it is
pointed out that it should not be confused
with the Cope elimination reaction. The
cross-references to other reactions described in this book are very helpful. The
book also contains a short list of selected
literature references. giving not only the
first publication in which each reaction is
described, but also important review articles enabling the reader to find out about
a reaction of interest in greater depth. It is
pleasing that the authors appear to have
made an effort to include some quite recent citations extending into the 1990s.
Brief name and subject indexes are provided at the end of the book.
The book by Hassner and Stumer covers
about 450 reactions, including some lesser
known ones, again arranged alphabetically. In the preface the authors rightly point
out that for reasons of space alone it is not
possible to include every reaction. and
that some whose mechanisms are likely to
be well known to every chemist have been
purposely omitted. Nevertheless, in view
of the fact that many reactions of a highly
specialized nature have been included, it is
surprising to find no mention of the mechanistically important and highly topical
Bergman cyclization. In many cases several closely similar reactions have been included. Each reaction is first described in
a single sentence, which is then followed
by a formula scheme for a specific example of the reaction, giving the reaction
conditions and in many cases also the
yield. A few relevant literature references
are listed, including the first paper describing the reaction and at least one review article. Lastly the experimental details
for carrying out the example reaction are
given. At the end of the book are indexes
according to names, reagents, and reaction types, as well as a fold-out “Functional Group Transformations Index” similar to those provided in the Compendium
of Organic Synthetic Methods.
What are the main differences, and
which book should be recommended? The
book by Laue and Plagens is certainly
aimed more at the needs of students, and
from that standpoint the inclusion of brief
summaries of the mechanistic background
is an important advantage. By cleverly limiting the coverage to about 130 reactions
the authors have allowed themselves sufficient space to do justice to the didactic
quality expected from a book intended for
students. The book by Hassner and Stumer
is clearly intended rather for the research
chemist in academia or industry. For this
readership, although it may still be important to give mechanistic information, the
main need seems to be for rapid access to
typical experimental conditions for the re936
action of interest. Whereas Laue and Plagens can best serve to complete the reader’s knowledge, Hassner and Stumer on
the other hand is more in the nature of a
resource for solving preparative problems. For the latter purpose one is not
necessarily looking for a named reaction,
but it is a fact that many of the most important reactions carry the names of their
originators. What is meant in the title by
“Unnamed Reactions”? There are none
of these in the book-by definition they
cannot even appear in the “Names Index”. The authors have given every reaction (at least) one name in its heading.
Probably the purpose of this part of the
book’s title is just to attract the attention
of potential readers.
Both books are well suited to their different purposes and can be recommended-this reviewer is glad to have them
both. However, a word of caution is in
order. These books and others like them
are eminently suitable for quickly learning
about a large number of reactions of organic chemistry, and many readers will
certainly find them very useful, for example when preparing for examinations.
Nevertheless, both the readers and their
teachers must always bear in mind that
knowing about a reaction is no substitute
for understanding it. These books are not
intended as alternatives to more detailed
textbooks, but are for quick reference, and
are best treated as an extension of the textbooks to be used judiciously. No well-constructed examination can be limited to
merely asking about named reactions, and
equally the memorizing of a “data bank”
of reactions is not sufficient to enable one
to succeed as a scientist.
Holger Butenschon
Institut fur Organische Chemie
der Universitat Hannover (FRG)
Chemical Generation and Reception
of Radio- and Microwaves. B y A. L.
Buchachenko and E. L. Frankevitch.
VCH Verlagsgesellschaft, Weinheim, 1994. 180 pp., hardcover
DM 135.00.-ISBN 3-527-89630-9.
“Spin chemistry”, i.e. the investigation
and utilization of magnetic field effects
and spin effects in chemical reactions, enjoys increasing popularity. The authors of
the present book like to distinguish between two generations of spin chemistry.
The first was concerned with the influence
of static magnetic fields, typical examples
being magnetic field effects (MFE) or
chemically induced dynamic nuclear and
electron spin polarizations (CIDNP and
:(? VCH ~rlug.F~eselIs~hhuff
mbH, 0-69451 Wi,inhrim. I995
CIDEP). In this book the emphasis is on
spin chemistry of the second generation,
which comprises the interactions with additional oscillating fields. These cause
radio-induced magnetic isotope effects
(RIMIE), stimulated nuclear polarization
(SNP), and microwave-stimulated quantum beats, and are exploited in reaction yield detected magnetic resonance
(RYDMR). In addition, the authors deal
with the reversal of such processes, namely the emission of coherent microwave radiation from chemically reacting systems.
In the first chapter, “Magnetic Scenario
of Chemical Reaction”, numerous examples are given to drive home the principle of spin conservation during chemical
transformations and thus spin selectivity
of chemical reactions. The second chapter
is a discussion of the radical pair mechanism, despite its misleading title, “Magnetic Interactions in Chemical Reactions”. The title of the third chapter,
“Magnetic Effects in Chemical Reactions”, also slightly misrepresents its actual content: except for a few introductory
sentences, it only deals with spin chemistry of the first generation. “Chemically
Induced Radio-Frequency Emission” is
only touched upon in the short (1.5 pp.)
fourth chapter, although from the title
of the book one would have expected
this to be a central topic. Four chapters
on RYDMR (“Reaction Yield Detected Magnetic Resonance-RYDMR”,
“RYDMR in Solids”, “RYDMR in Liquid Solutions”, and “RYDMR in Photosynthetic Systems”) are followed by two
others (“Radio-Induced Magnetic Isotope Effect” and “Microwave-Stimulated
Nuclear Polarization”) about spin chemistry of the second generation. The authors focus on examples and applications
rather than on detailed quantitative explanations of the theory of these effects.
In Chapter 11 (“Coherence in Spin Dynamics and Chemical Reactivity”) quantum beats are discussed. At the end of the
volume we find a very short chapter
(3 pp.) on “The Action of Electromagnetic Waves on Biological Processes”.
The most striking impression one receives when going through the book for
the first time is that it is written in alarmingly bad English. A few examples, quoted verbatim, may illustrate this; there are
numerous others of this kind. There are
frequent misspellings of proper names“Plank constant” (p. 3), “Schrodinger
equation” (p. 18), “Gann-diode” instead
of Gunn-diode (p. 76), “Abraham” instead of Abragam (consistently on p. 12.5
and p. 127), and chemical names“vinilene” (p. loo), “acetonitryl” (p. 129,
“dinucleatide” (p. 130).
OS70-0S33!95jOXt~S-0936$ 10.00 i
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Angrw. Chem. l n l . Ed. EngI. 1995, 34. N o . 8
BOOKS
~~
Often though, not only the laws of the
English language but also those of logic
are violated, and the reader is slowed
down trying to figure out the likely meaning: “The term (1 -A)F takes into account the unfavorable chance that the
pair, being transformed from triplet to
singlet and being ready to react, avoids
the reactions since A < 1” (p. 22); “If in
the course of the reaction some products
may be produced that have the same spin
as that of the pair, then the reaction proceeds” (p. 62); “The kinetic scheme gives
a qualitatively good picture o f a spectrum
of resonant variations in the rate constants away from crossing of intermediate
pair levels” (p. 1 13); “The spin of ion radical D’ at the moment of its recombination was conditioned by its evolution as
the spin of the hole while it was in a state
M + that was a precursor of D’” (p. 120).
The third of the foregoing examples is utterly incomprehensible (at least to the
present reviewer). both with and without
its context.
At times, the formulations verge on the
absurd : --page 11 : “Radical pair is a dynamic system from which the radicals can
diffuse apart, traveling randomly in space
and time, and then return and reencounter” page 126: “A small internal size of
a micelle where radicals can diffuse makes
us believe that the prominent part of their
lifetime will be spent suffering on exchange interaction”.
Looking more closely into the book,
one detects a good many errors in figures
and formulas. Again, some examples: In
Figures 1.1, 2.3, and 5.4 (bottom), vector
representations of the triplet states I T+,)
and I T- ,) are given, in which the phase
difference between the two vectors is 180“.
On the other hand, in the vector models of
Figures 2.2 and 5.4 (top) there is a phase
difference of 0”. What is the reader to
think if the same state is depicted in two
ways that are obviously quite different?
But in addition, even within the limitations of vector models, both these representations are wrong. In the first, the re~
Angen.. (’hcJni.Irrr. Ed. EngI. 1995, 34, No. 8
<i:j
sultant spin coincides with the z-axis,
which is a violation of the uncertainty
principle. In the second, combination of
two vectors representing spin-1/2 particles
would give a vector of wrong total length
(Phinstead of Ph).The correct way to
draw the diagrams for I T+1) and I T- 1) is
with a 90” phase difference.
For the magnetic moment of the
nucleus, we find pn = - q,(j,/h)J, i.e. the
wrong sign (p. 4). The same mistake
appears in the expression for the z-component of pn. On page 13, the dependence
of the sign of the electron Zeeman energies on the electron spin state is ignored.
In the expression on page 42 for the ratio
of the equilibrium populations of adjacent
nuclear energy levels, the denominator of
the Boltzmann term should have k T instead of 2kT. Anyone working in the field
of magnetic resonance will probably spot
these and similar errors at once. However,
the book aims at the non-specialist, for
instance at chemical physicists and physical organic chemists, as we read on its
cover.
In the equation for the S-T,-mixing
matrix element (Eq. 2.12 on p. 1 8 ) , the
sign of the second term is wrong. The
third term of the expression for the spinindependent probability of geminate recombination (Eq. 2.27 on p. 20) should
have p z instead of p . Et cetera; it is to be
doubted that a reader trying to get acquainted with spin chemistry will detect
such errors at a glance.
The later parts of the book contain
more than 50 equations, many of them
very specialized, and the derivations of
most of them are not given. The above
examples do not inspire great confidence
in their correctness.
Analyzing the references, some 200 in
number, and eliminating duplicate entries
and conference proceedings that are not
generally available, the reviewer found
only about 30 publications that were concerned with the main subjects of the book
and had appeared after 1987. One cannot
help noticing that the most recent refer-
VCH Vrrlugsjiesells~liufimhH, D-69451 Weinheim. 1995
ence pertaining to “Chemically Induced
Radio-Frequency Emission” dates back
to 1983, and that this was itself a review,
written by one of the authors of the
present book. Obviously, nothing of importance has happened in the latter field
during the last ten years, so why review it
anew? The cover text ”...first critical
overview in a decade ...” seems almost
ironical under these circumstances.
Finally, one puts aside the book with
the impression that the efforts of the two
authors have not always been well coordinated and that their treatment of the subject matter is somewhat imbalanced. For
instance, vector models and intersystem
crossing in radical pairs are discussed at
the beginning of Chapter2 and are explained in just as much detail a second
time in Chapter 5. Also, many formulas
appear in duplicate (Eqs. 2.4 and 2.11, 2.5
and 2.12, 2.6 and 2.34, 2.7 and 2.35, etc.);
the contents of Figures 1.1, 2.2 (top), and
5.4(a) are identical, apart from the inconsistencies mentioned above; the same
holds for Figures 2.3 and 5.4(b); and so
on. Basic concepts which should be
known to the group of scientists the book
is intended for, such as singlet and triplet
states and spin conservation in chemical
reactions, are treated at length (three
pages of examples to illustrate the latter
principle) and repeated frequently. In
contrast, throughout the book practically
all derivations and details of the calculations are skipped, and there are abrupt
jumps to rather specialized results. Is it
not one of the very purposes of a monograph to bridge the gaps between the fundamentals and the end results?
In summary. this book is probably of
little value for a “chemical physicist, physical organic chemist. material scientist,
radio- or biophysicist” (press release) in
general. Maybe the expert in the field of
spin chemistry could profit from it in
some points.
Martin Goez
Institut of Physical Chemistry
University of Braunschweig (FRG)
0570-0~33i95/080R-0937B 10.00
+ .Z.T;O
931
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