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Book Review Multiple Bonds and Low Coordination in Phosphorus Chemistry. Edited by M. Regitz and O. J. Scherer

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Noticeable in the first volume is the absence of several
classes of compounds containing by phosphorusxarbon
bonds : for example, P(IiI)-halogen compounds such as
halophosphanes, R,PX,-, (R = alkyl, aryl, etc.; X =
halogen; n = 1,2). These and related classes of compounds
will presumably be covered in the last volume of the series.
Whereas phosphaalkynes are discussed in detail in the first
volume, no mention is made of phosphaalkenes or systems
with P=P bonds. Furthermore, the subjects covered in Volume 1 and, eventually, in Volume 4 are closely related, although this is not stated explicitly. Perhaps Volume 4 should
have been planned to directly follow the first volume.
This volume lacks a chapter on the NMR investigations of
organophosphorus compounds, especially by 31P NMR
spectroscopy. However, several books that treat this subject
have been published recently. On the other hand, the ESR
spectra of free radicals derived from phosphanes are covered.
The author index is comprehensive, but the subject index
leaves much to be desired. To locate specific information,
therefore, a certain level of expertise is required. There are no
serious typographical errors, apart from the apparently unavoidable misspellings of names.
The first volume of this series appears to have achieved its
purpose, even though it is impossible to pass judgment on
the entire series. Rapid publication of Volumes 2-4 is highly
desirable, since the complete handbook promises to be very
useful to phosphorus chemists. Although the very high price
will limit wide availability of this first organophosphorus
volume of the Patai series, no large chemistry library should
be without it.
Reinhard Schmutzler [NB 1162 IE]
Institut fur Anorganische und Analytische Chemie
der Technischen Universitat Braunschweig (FRG)
Multiple Bonds and Low Coordination in Phosphorus Chemistry. Edited by M . Regitz and 0 .J2 Scherer. Thieme, Stuttgart 1990. xviii, 478 pp., hardcover DM 468.00.ISBN 3-13-752201-3
This volume entitled “Multiple Bonds and Low Coordination in Phosphorus Chemistry”, edited by M . Regitz and 0.
Scherer, features numerous articles on a variety of topics
which are comprehended by the title. The vast scope and
interest of this fascinating field is emphasized by the large
number of chapters (25) and the list of distinguished contributors. This research area, which originated in a number of
laboratories in the 1960s, is a relatively young one. As the
editors point out in their introduction, “hardly any other
field of phosphorus chemistry has undergone such a brisk
development in such a short time”.
The opening chapter by the editors provides a brief
overview of most, if not all, of the significant developments
in the field. This is followed by an excellent chapter on
“Bonding Properties of Low-Coordinated Phosphorus
Compounds” by W Schoeller. It begins by highlighting the
reasons for the differences between the lighter main group
elements and their heavier congeners. Many of the concepts
discussed here should eventually be included in undergraduate inorganic textbooks. They will, one hopes, replace the
often unsatisfactory “explanations” of such differences that
are in current use. The emphasis is, of course, on phosphorus
but the chapter should be of general interest to many
chemists from a wide variety of areas. There is also much
useful factual information on structures, bond strengths,
Angen. Chem. Int. Ed. Engl. 30 (1991) No. 8
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molecular energy levels and computational work concerning
phosphorus compounds.
The bulk of the remaining chapters are classified (not always accurately) according to whether the phosphorus coordination number is 1, 2 or 3.
Three chapters concern phosphorus coordination number 1. The first, dealing with phosphinidenes, is further divided into two parts which cover in situ generated phosphinidenes (by E Mathey) and binuclear or bridging
phosphinidenes (by G. Huttner and H . Lang). Owing to the
extreme reactivity of the R-P: fragment, none of the stable
compounds in this chapter involve singly coordinated phosphorus. The phosphinidenes are detected either spectroscopically or by trapping with transition metal-ligand fragments
or organic and related substrates.
The second in the series of chapters on one-coordinate
phosphorus (by M . Regitz and P . Binger) deals with the
phosphaalkynes (PEC-R). These are the phosphorus analogues of nitriles, and the existence of such species has been
recognized for over 40 years. It was, however, the seminal
discovery (by Becker in 1981) of a facile route to kinetically
stabilized examples that has virtually created this field of
investigation. The explosive growth in this area may be
gauged from the fact that within 8 years (up to mid-1989) of
the initial report about 200 papers have appeared on this
subject. This chapter gives a comprehensive and well organized account of these developments.
The final chapter on one-coordinate phosphorus compounds (by 0. Scherer) is concerned primarily with bonding
and ligand properties of phosphorus units such as P=N,
PEP and P,. The two former units have no existence as stable
separate entities under ambient conditions, although a related
ionic species [P=N-RI0[AICl,le has been structurally characterized recently. The vast majority of the work in this area has
concerned P, species as ligands in transition metal complexes.
In almost all of these complexes the phosphorus is at least
two- or even three-coordinate, so that the inclusion of these
compounds in this particular section is somewhat surprising.
The second major part of this volume concerns phosphorus with coordination number 2. This section is the largest
part of the book and comprises eleven chapters. Even so, not
all types of two-coordinate phosphorus compounds are dealt
with here, and there is virtually no coverage of two-coordinate phosphorus anions such as [PR,le or of two-coordinate
radical species such as [:PR,], some of which are stable at
room temperature. The largest chapters in this section are
those by R . Appel dealing with the phosphaalkenes, phosphacarbaoligoenes and phosphaallenes, and by G. Mark1
dealing with compounds that have phosphorus as part of an
aromatic six-membered ring. There is also a chapter (by A .
Schmidpeter) that deals with the delocalized five-membered
rings involving phosphorus and a variety of heteroatoms.
Acyclic delocalized two-coordinate phosphorus systems are
covered by chapters on phosphenium cations (by M .
Sanchez, M . R . Mazieres, L . LamandP, R . Wow) and on 2phosphaallylic cations (by A . Schmidpeter). The remaining
chapters in this section are concerned with various classes of
two-coordinate phosphorus compounds. Included here are
the landmark diphosphenes ( M . Yoshifui), the iminophosphenes (E. Niecke) and phosphorus compounds with multiple
bonds to boron, silicon, germanium and tin ( E Bickelhaupt).
Included also is a treatment of multiple bonds between two
phosphorus atoms with different oxidation states and the
closely related phosphinylidenesulfuranes (by A . Schmidpeter). The section is concluded by a chapter by L. D . Quin
and J2 Szewczyk on the oxophosphanes and their sulfur and
selenium analogues.
Verlagsgesellschaft mbH, W-6940 Weinheim, 1991
OS70-0833/91jO808-1047 S 3.50+.2510
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The third major section of the book deals with phosphorus
compounds with coordination number 3. While this is not
normally regarded as a low coordination number for phosphorus, the compounds covered by this section certainly are
unusual. There are eight chapters here, all of which concern
pentavalent phosphorus involved in multiple bonding to either C, N, P, 0, S or Se. The first three (by R. Appel, H.
Heydt, E. Niecke and D. Gudat) deal with phosphoranes
which have at least two multiple bonds to carbon, nitrogen,
or a combination of these with bonds to 0,S or Se. A chapter
(by M . Yosh(fiuji) is devoted to phosphoranes involving double bonds to phosphorus in combination with double bonds
to carbon, nitrogen, oxygen, sulfur or selenium. In addition,
an article by M . Meisel deals with dioxo- and dithioxophosphoranes and the elusive metaphosphate anion. The two
remaining chapters in this section by G. Bertrandand by 1-P.
Majoral are concerned with pentavalent phosphorus compounds with triple bonds to carbon or nitrogen. The final
chapter in the book (by K. Karaghiosoff) is an extremely
useful summary of 31P NMR data for low-coordinate and
multiply bonded phosphorus compounds.
In summary, this volume covers most of the exciting developments in this field over the last 25 years or so. The list of
contributors includes many of the leading figures who made
much of this chemistry possible. The literature is scanned up
to mid-1989 which, of necessity, means that many of the
chapters are already out of date owing to the extremely rapid
pace of development in these areas. Many readers will probably be aware that much, if not quite all, of the material
within its covers has been previously reviewed in the literature-in some cases more than once. The main advantage
with the present volume is that it saves you the trouble of
searching for these reviews in the literature. Some of the
chapters also serve to update the small number of areas that
have not been reviewed within the last five years or so. The
book is beautifully produced and is amply illustrated
throughout. The standard of writing is, on the whole, excellent and there are only a few obvious typographical errors.
Unfortunately, this attention to detail and presentation also
exacts a price which, at around $300, few individuals can
afford. In these days of budget restrictions, even many
libraries will be forced to look askance at such an expenditure for a single volume. Having said that, I can think of few
books that more effectively summarize so many of the most
exciting developments in phosphorus chemistry over the last
25 years.
Philip P. Power [NB 1158 IE]
Department of Chemistry
University of California
Davis, CA (USA)
Cathodolurninescence. Theory and Applications. By L. Ozawa. VCH Verlagsgesellschaft, Weinheim/VCH Publishers,
New York/Kodansha, Tokyo 1990. x, 308 pp., hardcover
DM 196.00.--ISBN 3-527-27982-2/0-89573-936-4/4-06204033-6
Cathodoluminescence is the physical process which is used
in TV screens and Braun tubes of scientific instruments such
as oscilloscopes to generate pictures by means of an electron
beam. The electrons are accelerated in vacuum by a voltage
of several kV and directed onto a screen containing small
crystals of a material which emits visible luminescence when
it is hit by the electron beam. Lyuji Ozawa’s book gives an
introduction to the physics of cathodoluminescence, and
1048
0 VCH
Verlagsgesellschaft mbH. W-6940 Weinheim. 1991
contains detailed information on a large number of important luminescent crystals and their fields of application. It
consists of three main parts.
The first part, which consists of Chapters 1 to 5, describes
the fundamental principles of the generation of light by irradiating energetic particles into suitable luminescent materials. These materials, which are called “phosphors”, are usually insulating or semiconducting inorganic crystals doped
with a small amount of ions of a transition element. The
latter emit the luminescence and are therefore called “activators”. After a short introduction in Chapter I , the author
describes in Chapters 2 and 3 the basic effects of the irradiating electrons on crystals and activator ions. The important
process which distributes the energy in the surface layer of
the crystal is the excitation of secondary electrons by inelastic scattering of an incoming high-energy primary electron.
The majority of the secondary electrons have rather low
energies of only a few electron volts, and they give rise to the
luminescence of the dopant ions, mainly via electron-hole
recombination. Several possible mechanisms of the excitation of the ions are discussed. Since the energy is transferred
from a primary electron to the luminescent centers via secondary electrons or electron-hole pairs, the motion and energy conversion of charge carriers play an important role in
phosphor crystals. These topics are addressed in Chapters 4
and 5. It is shown how the motion can be investigated by
varying the concentration of the activator ions, and by irradiating pulsed electron beams of different pulse durations
into the samples. As a result of such measurements, an explicit model of the cathodoluminescence is proposed for the
system Y,O,S:Eu.
After these general considerations, the second part of the
book (Chapters 6 and 7) provides more detailed information
on the optimization of cathodoluminescence phosphors for
applications in picture tubes. Chapter 6 addresses some basic
physical variables which should or should not be optimized
in phosphor materials. It is shown, for instance, that the
presence of a charge transfer band between activator ions
and host crystal is not important for obtaining an efficient
cathodoluminescence phosphor. On the other hand, the
choice of the optimum activator concentration plays a much
larger role. On the one hand, it is desirable to achieve an
efficient radiative recombination of electron-hole pairs, but
on the other hand, self-concentration quenching effects
should be avoided as far as possible. The optimum concentrations are usually below one mole per cent. Other variables
that can be adjusted are the crystal size and crystal structure
of the phosphor. In Chapter 7 the author discusses some
methods and engineering tricks to obtain bright cathodoluminescence picture tubes. He shows, for instance, how
microcrystals of appropriate shape and uniform size can be
grown. He also describes the best methods of measuring
cathodoluminescence intensities on phosphor screens.
In the third part, which comprises Chapters 8 to 10 and
occupies almost half the book, the author lists special properties of a large number of phosphorescent materials. Since
it contains many luminescence spectra and other technical
details, it will be useful for engineers working in this field.
Chapter 8 describes the properties of rare-earth-activated
phosphors. Because the visible part of their luminescence
spectra consists mainly of relatively few sharp lines, they can
be used in color TV screens. A different class of phosphor
materials are semiconductor crystals of compounds of elements of Groups I1 and VI, which are the subject of Chapter 9. Their most important representatives are ZnSe and
ZnS. They are characterized by broader luminescence bands,
so that they can be used in monochrome screens. By adding
0570-0833i91j0808-1048 $3.50+ ,2510
Angew. Chem. Inr. Ed. Engl. 30 (1991) No. 8
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