Table Of ContentMetal Clusters in Chemistry
Edited by
P. Braunstein
L. A. Oro
P. R. Raithby
Further Titles of Interest
A. Togni, R. L. Halterman (Eds.)
Metallocenes
Synthesis, Reactivity, Applications (2 Volumes)
1998.3-527-29539-9
Industrial Inorganic Products
An Ullmann’s Encyclopedia (6 Volumes)
1998, 3-527-29567-4
M. Beller, C. Bolm (Eds.)
Transition Metals for Organic Synthesis
Building Blocks and Fine Chemicals (2 Volumes)
1998.3-527-29501-1
E. C. Constable
Metals and Ligand Reactivity
1996, 3-527-29277-2
Metal Clusters
in Chemistrv
J
Edited by P. Braunstein
L. A. Oro
P. R. Raithby
Weinheim New York Chichester
Brisbane Singapore Toronto
Prof. Dr. P. Braunstein Prof. L. A. Oro Dr. P. R. Raithby
Lab. de Chimie de Coordination Dept. of Inorganic Chemistry Dept. of Chemistry
UniversitC Louis Pasteur I. C. M. A. - Faculty of Science University of Cambridge
4, rue Blaise Pascal University of Zaragoza-CSIC Lensfield Road
F-67070 Strasbourg CCdex E-50009 Zaragoza GB-Cambridge CB2 1EW
This book was carefully produced. Nevertheless, editors, authors and publisher do not
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in mind that statements, data, illustrations, procedural details or other items may
inadvertently be inaccurate.
Cover picture: Prof. Dr. A. Miiller, University of Bielefeld, Germany
Library of Congress Card No.: applied for
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Metal clusters in chemistry / ed. by P. Braunstein ... - Weinheim ;
New York ; Chichester ; Brisbane ; Singapore ; Toronto : Wiley-VCH 1999
ISBN 3-527-29549-6
0 WILEY-VCH Verlag GmbH, D-69469 Weinheim (Federal Republic of Germany), 1999
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Preface
Metal clusters occupy a central role in chemistry. Aspects of cluster chemistry im-
pinge on branches of the subject ranging from organometallic chemistry, through
coordination chemistry, homogeneous and heterogeneous catalysis to solid-state
chemistry and catalysis. Research in metal clusters is an interdisciplinary enterprise
that has exploded rapidly in importance over the past twenty years because metal
clusters exhibit increasingly interesting bonding as well as electronic, structural and
physical, and chemical and catalytic properties. Several reviews and books have
appeared in the past emphasising the key role that metal clusters play in chemistry,
materials science, nanotechnology and catalysis, but no up to date single source
dealing with the recent developments in metal cluster chemistry is currently avail-
able. The purpose of this book is to provide a general source of references for
workers including experimental and theoretical chemists and physicists in this
interdisciplinary field, and covering both fundamental and applied science. It is,
however. also directed at graduate students and scientists who have not previously
been involved in research into metal clusters. The vast majority of the metal clusters
considered in this book follow the definition offered by Cotton and others, namely,
complexes containing three or more metal atoms held together, at least in part, by
metal-metal bonds, although sometimes for the sake of convenience dinuclear
complexes with metal-metal bonds are included. Thus, the existence of metal-
metal bonds distinguishes cluster complexes from polynuclear cage complexes.
This book originates from the Scientific Network of the European Science Foun-
dation (ESF), which was initiated in 1992, with the aim of promoting the inter-
actions between European laboratories working in the field, as well as stimulating
multidisciplinary efforts and identifying frontier areas. Several workshops and
Euroconferences associated with this Network were held during the period 1992-
1998. The three volumes present a coordinated set of contributions written by leading
European scientists who have been involved in the ESF Network activities. We are
aware that research into metal clusters has also been very active in non-European
countries. Therefore, in order to pay tribute to these contributions, leading scientists
vi Preface
from outside Europe have been invited to add their personal views to the different
sections covered by this book on Metal Clusters in Chemistry.
The first volume of this book covers the topics of molecular metal clusters, the
second volume contains sections on metal clusters in catalysis and dynamic and
physical properties of metal clusters. Volume 3 covers the chemistry of nano-
materials and of solid-state clusters. It also contains an update of the reviews pub-
lished on metal clusters in the last ten years, and finally presents a view on further
developments in cluster chemistry leading into the next millennium. In general, the
sections within the book contain a blend of experimental results together with an
analysis of theoretical aspects of the work. In some instances, closely related areas
have been discussed by several authors and here a complementary diversity of views
is offered. The editors wish to thank the authors for their contributions to this book
and the numerous scientists who have been involved in Network activities, they
have all greatly assisted in the project by their vitality and enthusiasm for this
developing area.
We hope that this book will offer a source of ideas for future research develop-
ments. Cluster chemistry is still a young science that continues to grow rapidly. The
diversity within the subject area is so large that it is now possible, with time and
effort, to identify emerging patterns, such as structure-reactivity relationships, and
to analyse them. Clearly, the apparent cooperative phenomena between two or
more metal centres depend on the ability of the metal to “talk” to each other, either
by direct metal-metal interactions or through ligand bridges. We firmly believe that
the search for applications in quite different fields including the construction of
metal clusters with desired electronic and catalytic properties will be of fundamental
importance in the coming years. In this book it is our aim to show that metal cluster
chemistry is an active, multidisciplinary and international research area with a rich
past and a bright future, and to stimulate further interest in and enthusiasm for the
subje ct .
P.B.
L.A.O.
May, 1999 P.R.R.
Contents
Preface ............................................................... v
Volume I: Molecular Metal Clusters
1 Molecular Clusters. .................................................. 1
General Introduction ................................................. 3
FA. Cotton
1.1 Molecular Clusters - An Overview .................................. 8
M. H. Chisholm
1.2 Expanding, Degrading, and Rearranging Hexametal Boride
Clusters .............................................. ... 10
C. E. Housecvoft
1.2.1 Introduction .... ... ................................... 10
1.2.2 Expansion. .......................... .................. 12
1.2.2.1 Expansion beyond Mh during syntheses and ligand substitution
reactions of Mg borides. ...............................
1.2.2.2 Expansion from Mg cages using group 11 metal frag
1.2.3 Degradation ........................................................ 18
1.2.4 Rearrangements ............................... ................ 20
1.2.4.1 Conversion of trigonal prismatic to octahedra
1.2.4.2 Interconversion between cis- and trans-isomers of octahedral
R u ~ M ~(MB = Ir or Rh) borides .......................
1.3 Steric Effects in Metallacarboranes. ................................ 26
A.J. Welch
1.3.1 Introduction ..................... .................. 26
viii Contents
1.3.2 Minor consequences ................................................ 32
1.3.3 Major consequences ................................................ 34
1.3.3.1 Polyhedral deformation ............................................ 34
1.3.3.2 Low-temperature isomerization .................................... 39
1.3.4 Conclusions and outlook ........................................... 44
1.4 Heteronuclear Clusters Having Transition Metals and
Metals of Group 14.,. .............................................. 48
D . J . Cardin
1.4.1 Introduction ........................................................ 48
1.4.2 The coordination of diorganogroup-14 element compounds ...... 49
1.4.3 Synthetic approaches ............................................... 50
1.4.4 Compounds in which the group 14 ligand is bonded terminally
to a cluster .......................................................... 51
1.4.5 Compounds in which the group 14 ligand doubly bridges
metals in a cluster without further reaction ........................ 54
1.4.6 Clusters in which the Group 14 ligand or the heterometallic
cluster has undergone further reaction ............................. 65
1.5 Hetero-Metal Clusters by Assembling Amino Substituted
Subvalent Main Group Metals and their Ligand Reactions ........ 73
M . Veith
1.5.1 Introduction ........................................................ 73
1.5.2 Syntheses of clusters by using MezSi( NtBu)zM (M = Ge( 11),
Sn(I1)). .............................................................. 74
1.5.3 Conclusion .......................................................... 89
1.6 Synthetic Pathways to a Neglected Class of Compounds:
Organobimetallics of Aluminium and cobalt ........................ 91
J . J . Schneidev
1.6.1 Introduction ........................................................ 91
1.6.2 Synthesis of mixed group 13/transition metal complexes .......... 92
1.6.2.1 Transition metal bonds to Ga, In and T1 .......................... 92
1.6.2.2 Transition metal (tm) bonds to B and A1 .......................... 95
1.6.3 Synthetic routes to organobimetallic compounds of Co and A1 .. 100
1.6.4 Outlook and trends ................................................ 106
1.7 Group 5 and 6 Bimetallic Complexes with Phosphido Bridges:
Syntheses and some Structural Features ........................... 110
G. Boni, M . M . Kiibicki and C. Moibe
1.7.1 Introduction ....................................................... 110
1.7.2 Synthesis of metallophosphines ................................... 110
Contents ix
1.7.3 Bimetallic complexes from metallophosphines. ................... 1 14
1.7.3.1 Monobridged complexes .......................................... 1 15
1.7.3.2 Dibridged complexes .............................................. 116
1.7.4 Bimetallic complexes from metallodiphosphines ................. 1 19
1.7.5 Molecular structures of phosphido bridged complexes ........... 120
1.8 Polythiometalates and Polyoxothiometalates Based on Acido-
Basic Condensation Processes ..................................... 124
F. Skheresse, E. Cudot and C. Sinwnnrt-Jeyat
1.8.1 Introduction .......................... .................. 124
1.8.2 Thiometalates and catalysis ........................
1.8.3 Academic research induced by catalysis ...........
1. 8.3.1 Sulfido-ligands ................ .......................... 127
1.8.3.2 Disulfido-ligands ...........
1.8.3.3 Vanadium systems.. ......................................
1.8.3.4 The [MzS2X2I2+X -0, S fr
1.8.3.5 CS2 activation .............
1.8.4 Reactions of thiometalates
1.8.4.1 Selective sulfuration of fully oxygenated polyoxoanions ......... 136
1.8.4.2 Addition of a thiometallic fragment on a lacunary polyanion
1.8.4.3 Self-condensation of the [Mo2S202I2' fragment. ................ 139
1.9 Electronic Effects on the Shape of M2X2 Frameworks (X =
Naked Chalcogenide Atom, M = Late Transition Metal). . 143
C. Mealli and A. Ovlirndini
1.9.1 Introduction .......................... ...................... 143
1.9.2 .............................. ........ 146
1.9.2.1 n less electron rich M2X2 pl etons . . 146
1.9.2.2 Puckering of the MlX2 skeletons ............................. 150
1.9.2.3 Coupling/ uncoupling of dichalcogenide within puckered
...................... ........................ 152
1.9.2.4 Coupling of chalcogenide atoms in electron rich M2X2
planar frameworks. ............................
1.9.2.5 Uncharged and dic plexes of the type L2MX2
1.9.3 Conclusions ........................... .................. 160
1.9.4 Appendix ...................................
1.10 Towards Transition Metal Clusters by Reaction of Simple
Metal Carbonyls with Chalcogenides and Chalcogenolates
G. Henkel and S. WriJgruber
1.10.1 Introduction ................. ......................
1.10.2 Synthetic aspects.. ................................................. 164
