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Book Review Clusters and Catalysis Metal Clusters in Catalysis. Edited by B. C. Gates L. Guczi and H

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Fig. 4. Experimental images of YBa2Cu3O,-* a) [IOO] projection, the computation conditions of the inset: resolution
of 1.98
defocus of - 1800 and thickness of 60
und c) [OIO] projection, the computation conditions of the
insets: resolution of 1.98 defocus of - 1200 A; thickness
of 60 (b) and 80 (c).
20 /i
0.5 at the four sites on the ab plane, the differences in the
images along the [OIO] and [loo] directions is much reduced.
By choosing a resolution for the computed image close
to that used by us experimentally (1.98 to 2.00 A) we find
that there are now clear-cut differences between the computed images of the structure containing aligned oxygen
vacancies for the [IOO] and [OlO] projections (see Fig. 3).
Our experimental results, Figure 4a from one particle
and Figures 4b,c from- other regions of another particle,
show different details of image contrast. The inset of Figure 4a is identical to that shown in Fig. 3e. None of the
images calculated along [OlO] matches this experimental
result. The insets of Figures 4b and c are identical to those
from Figures 3c’ and d’ respectively. The sample-thickness
dependence of these two images match only with those
found experimentally for projections along [Ol 01.
I n summary, we have demonstrated that, in principle, it
is possible by high resolution electron microscopy, to observe contrast effects arising from the presence of a given
oxygen vacancy arrangement in the a b plane of
YBa2Cu30,-A. Further studies of this system, with
largerl’3”51values of 6, are underway.
Received: June 23, 1987 [Z 2308 IEJ
German version: Angew. Chem. 99 (1987) 1063
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Clusters and Catalysis
The above title has in recent years become a catchphrase
used in support of research on clusters, especially in the
USA. Although opinions may differ about the use of a
phrase which contains such promises, it has nevertheless
gained attention and funding for cluster research, and led
to increased activity in this area. Consequently the appearance of monographs on the theme “Clusters and Catalysis” was only a question of time. That has now occurred in
the two books
Metal Clusters in Catalysis. Edited by B. C. Gates, L. Guczi, and H . Knozinger. Elsevier, Amsterdam 1986, xxv,
648 pp., bound, HFI 195.00.--ISBN 0-444-42708-2, and
Metal Clusters. Edited by M . Moskovits. Wiley, ChiChester 1986. ix, 313 pp., bound, L 47.95.-1SBN 0-47189388-9
and more will probably follow. In both cases the editors
d o not come from the field of preparative cluster chemistry, which is mostly associated with inorganic chemistry,
but instead come from physical chemistry. The book of
over 600 pages edited by Gates, Guczi, and Knozinger
Angew Chern I n t . Ed. Engl. 26 (1987) No. 10
states its aims in the title, whereas in the volume of 300odd pages edited by Moskovits the definition of subject
matter first appears in the list of contents. Both books are
priced at a level which today is normal for monographs of
this kind, both give about the same amount of paper in
relation to the price, and both can be described as collections of review articles. In both cases the editors have enlisted a competent team of authors (seventeen in “Metal
Clusters in Catalysis” and ten in “Metal Clusters”), from
whose names specialists in the field will be able to predict
the subjects covered, and also those that receive little attention. Altogether one can say of both these books that
they deal with the essential highlights of the chemistry of
cluster compounds, mainly those without organic ligands.
“Metal Clusters in Catalysis” is divided into three sections, which can be defined as molecular cluster chemistry,
clusters in and on supports, and some analogies between
clusters and surfaces. In the first part G. L. Geoffroy gives
a short but complete survey of synthetic methods for molecular clusters, which is followed by a very brief article by
the same author on cluster structures. Likewise very brief
is the article by J. A . Connor on thermochemistry and
binding energies in clusters. The essay on reactivities of
molecular clusters by G. Lavigne and H . D . Kaesz which
comes next is well organized and essentially complete. The
article by L. Marko and A. Vizi-Orosz on homogeneous catalysis by metal clusters is the fullest review yet to appear
on this topic. The second part of the book contains its
main emphasis, in accordance with the editors’ chief area
of interest. The chapter by H . Knozinger. L. Guczi, and R .
F. Pettifer on characterization by physical methods is very
detailed, carefully written, and longer than all the preceding five chapters put together. The chapter by G . A . Ozin
and M. P. Andrews on clusters produced by the condensation of metal vapors is authoritative and comprehensive.
The treatment by P. A . Jacobs of clusters in zeolites emphasizes the great hopes which are held for developments
in this area. This is followed by the second principal chapter of the book, to which B . C . Gates. R . Psaro, R . Ugo, G.
Maire. and H . Knozinger have contributed; this is concerned with clusters immobilized on surfaces, their preparation from molecular clusters, and the associated organometallic surface chemistry. The following chapter by
L. Guczi on surface bound bimetallic catalysts is actually a
sub-chapter of the preceding one. The third section of the
book consists of only a single essay, in which G. Ertlimpressive as always-discusses relationships between
clusters and surfaces. Although the book, with 648 pages,
is by no means thin, it cannot be said that any of the eleven
chapters is unduly long.
In “Metal Clusters” the emphasis is very unevenly distributed between individual topics. General themes are
treated very briefly: bonding theory considerations (by R.
C . Baetzold), structures (by D. H . Farrar and R . J . Goudsmit), organometallic chemistry involving clusters (by J. S .
Bradley), and catalysis by surface bound clusters (by B. C .
Gates). In contrast, two chapters on individual special topics, namely reaction kinetics of metal carbonyl clusters (by
A. J. Poe) and optical methods for identifying cluster compounds in the gas phase (by J. L. Gole), are very detailed.
The book is rounded off by an account of methods for
identifying matrix-isolated clusters (by the editor, M . Moskouits), and two applications-oriented chapters, on clusters
in zeolites (by P. Gallezot) and on a comparison of the catalytic activities of surface bound clusters (by A . Brenner).
Thus the book’s rather general title conceals a collection of
essays on particular aspects of cluster chemistry, deterAngew. Chem I n [ Ed. Engl. 26 11987) No. 10
mined by the choice of authors, the main emphasis being
on describing the properties of metal atom aggregates.
The field of cluster chemistry as a whole is already so
large that these two books, even when taken together, can
present only a selection from it. Regarding the selections
that have been made, they are to some extent complementary, but they overlap on matrix isolation, clusters in zeolites, structure geometry, and clusters on supports. On the
last topic we also find the same author, B. C . Gates, in
both books. Both books are attractively produced; the detailed index in “Metal Clusters in Catalysis” is an additional good feature. Both books have their strengths and
weaknesses, of course, since they can be no better than the
individual contributions of their authors. As monographs,
however, they offer a very good account of the present
state of knowledge on the topics treated, and therefore
should not be omitted from any library. So far as purchase
by individuals is concerned, though, they will only be of
interest to specialists, particularly in the case of “Metal
Clusters”. Even when one accepts that the very brief treatment of molecular cluster chemistry is in accord with the
editors’ stated aims, it would nevertheless have been desirable to include some discussions of the chemistry of soluble cluster compounds with inorganic ligands, the redox
properties of clusters, the extensive topic of clusters in
solid state compounds, and the biological importance of
clusters. Since the phase of frantic activity in cluster chemistry is coming to a n end and the matter is becoming somewhat settled now, perhaps some author should risk writing
a textbook type monograph on the subject.
Heinrich Vahrenkamp [NB 825 IE]
Institut fur Anorganische Chemie
der Universitat Freiburg (FRG)
Analytical Methods in Human Toxicology, Part 2. Edited
by A . S . Curry. VCH Verlagsgesellschaft, Weinheim
1986. x, 354 pp., bound, DM 170.00.--ISBN 3-52726285-7
The second volume of “Analytical Methods in Human
Toxicology” deals with HPLC, fluorescence analysis and
radioimmunoassay methods, and their application to solving toxicological problems. In addition it familiarizes the
reader with pharmaco-kinetic investigations. Using examples from the literature, the large differences often found
in metabolization of pharmaceutical substances are discussed, together with the related concept of the “effective
dose”. Lastly, procedures used to test for the presence of
some toxicologically important classes of compounds,
such as narcotics and combustion gases, are described in
detail; other classes of substances, e.g. barbiturates, benzodiazepines and tricyclic antidepressants, are included in
the discussion of practical examples.
The book includes references to a considerable amount
of literature which is important to the toxicologist. Some
chapters contain a wealth of very useful advice, e.g. in the
section o n the elimination of errors in HPLC. Unfortunately, though, the editor has not succeeded in this second volume in avoiding some duplication of material, e.g. the analysis of tricyclic antidepressants has already been treatedthoroughly in volume 1. Despite this lack of complete coordination, every toxicological laboratory will find that this
second volume too is a valuable addition to its library.
Gerhard Spiteller [NB 827 IE]
Lehrstuhl fur Organische Chernie
der Universitat Bayreuth (FRG)
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