Landmarks in organo-transition metal chemistry: a personal view

360 Pages·2009·8.8 MB·English

by  Helmut Werner

Landmarks in Organo-Transition
Metal Chemistry
Profiles in Inorganic Chemistry
Series Editor:
John P. Fackler, Texas A & M University, College Station, Texas
Current Volumes in this Series:
Landmarks in Organo-Transition Metal Chemistry: A Personal View
Helmut Werner
From Coelo to Inorganic Chemistry: A Lifetime of Reactions
Fred Basolo
AContinuationOrder Plan is available for this series. A continuation order will
bring delivery of each new volume immediately upon publication. Volumes are
billed only upon actual shipment. For further information please contact the
publisher.
Helmut Werner
Landmarks in
Organo-Transition
Metal Chemistry
A Personal View
1 3
Helmut Werner
Institute of Inorganic Chemistry
University of Wu¨ rzburg
Germany
ISSN: 1571-036X
ISBN: 978-0-387-09847-0 e-ISBN: 978-0-387-09848-7
DOI 10.1007/978-0-387-09848-7
Library of Congress Control Number: 2008940859
# Springer ScienceþBusiness Media, LLC 2009
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Printed on acid-free paper
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To Monika, Andreas, and Annemarie
And in Loving Memory of Helga
Foreword
Organometallic chemistry has witnessed an exponential growth in the past half
decade, and today is represented at its frontiers by the second edition of a multi-
volume text, two major journals and a plethora of monographs. Helmut
Werner, a pioneer who has contributed extensively to the field, now offers us
a personal view of important areas of transitionmetal chemistry. It is unusual in
that it provides an historical perspective on some of the more significant
developments in this area. He writes both with a great generosity of spirit and
an obvious love of the subject. It is evident that both for him, and now his
readers, it is not only the science, but also its protagonists, that are the focus of
much attention.
The first two chapters provide interesting information on Helmut’s family
and scientific background, culminating in hisWu¨ rzburg C4 professorship (since
1975); he has mentored 110 Ph.D. students and 40 postdoctoral and visiting
scientists. He continues in Chap. 3 to provide an account of the birth of the
subject and its development in the nineteenth century. Subsequent chapters deal
with metal carbonyls and derived clusters, the discovery of ‘‘sandwich’’ com-
pounds, triple-decker analogues, metal–ethene complexes and their congeners,
metal carbenes and carbynes, and finally metal alkyls and aryls. Each chapter
has ample references. Helmut’s account is exceedinglymodest; from around 800
citations, less than 20 are to his own contributions. The text is well illustrated
with formulae, reaction schemes, biographies and photographs.
The work is of very high quality and the author is to be congratulated on
having given us a very informative and eminently readable and enjoyable book.
He clearly has a profound knowledge of the subject and, as one of its leading
practitioners, offers his readers a unique overview. I commend it with confi-
dence and much enthusiasm.
July 2008 Michael Lappert
vii
Series Preface
A renaissance in the field of inorganic chemistry began in the middle of the
twentieth century. In the years following the discoveries of A. Werner and
S. M. Jørgensen at the turn of the century, the field was relatively inactive.
The publication of Linus Pauling’s Nature of the Chemical Bond in 1938 and
World War II shortly thereafter launched this renaissance. The war effort
required an understanding of the chemistry of uranium and the synthetic
actinide elements that were essential to the production of the atom bomb.
There was also a need for catalysts to produce rayon, nylon, synthetic rubber,
and other new materials for the war effort. As a result, many gifted chemists
applied their talents to inorganic chemistry. Profiles in Inorganic Chemistry
explores the roles some of the key contributors played in the renaissance and
development of the field.
Some of the early leaders in this reawakening are now deceased. Pioneers
included John Bailar at the University of Illinois, W. Conard Fernelius, at
Pennsylvania State University, and Harold Booth at Western Reserve Univer-
sity, who with some others, started the important series entitled Inorganic
Syntheses. Several inorganic chemistry journals were born, as were various
monograph series including the Modern Inorganic Chemistry series of Springer.
Geoffrey Wilkinson, who along with E. O. Fischer was the first inorganic
chemist since Werner to win the Nobel prize, started his career at Harvard in
about 1950 but later that decade moved to the University of London’s Imperial
College. By then, Ron Nyholm already was building a strong inorganic pro-
gram at the University of London’s University College.
Physical and mathematical concepts including group theory gave inorganic
chemists new tools to understand bonding, structure, and dynamics of inor-
ganic molecules. Fischer,Wilkinson, and their contemporaries opened up a new
subfield, organometallic chemistry, out of which many metal-based catalysts
were developed. It was soon realized that many inorganic minerals play essen-
tial roles as catalysts in living systems. As a result, another subfield, bioinor-
ganic chemistry, was born. The discipline of inorganic chemistry today includes
persons of many different walks of life, some creating new material and cata-
lysts, others studying living systems, many pondering environmental concerns
ix
x Series Preface
with elements such as tin, mercury, or lead, but all focusing on questions outside
the normal scope of organic chemistry.
Organic chemistry has enjoyed a long history as a great science, both in
Europe and the United States. During the past 15 years or so, many of the U.S.
contributors have produced interesting autobiographies as part of an American
Chemical Society series entitled Profiles in Inorganic Chemistry. There is also,
however, a need to have students and scientists of inorganic chemistry under-
stand the motivating forces that lead prominent living inorganic chemists to
formulate their ideas. I am grateful that Springer has undertaken to publish this
series. These profiles in inorganic chemistry will portray the interesting and
varied personalities of leaders who have contributed significantly to the renais-
sance of inorganic chemistry.
College Station, TX John P. Fackler, Jr.
Preface
In the short period between December 1951 and February 1952, two papers
appeared which laid the roots for what a few years later was called by Sir
Ronald Nyholm The Renaissance of Inorganic Chemistry. Two research groups,
working in completely different fields, reported the isolation of a seemingly
simple iron compound of the analytical composition FeC10H10 which quite
soon became the flagship of a new chemical discipline. It was not the composi-
tion of the new compound but its surprising and absolutely unexpected mole-
cular structure that stimulated both experimental and theoretical chemists.
While in the nineteenth and even in the first half of the twentieth century, it
usually took decades before an epoch-making idea such as the cyclic structure
of benzene, the tetrahedral configuration of methane, or Alfred Werner’s con-
cept of coordination compounds has been accepted, the synthesis and structural
elucidation of bis(cyclopentadienyl)iron FeC10H10 – later called ferrocene –
initiated immediately a research avalanche for which there is almost no pre-
cedent. In less than 20 years, not only metal compounds containing planar
three-, four-, five-, six-, seven- and eight-membered ring systems were prepared,
but at the same time also the chemistry of compounds with metal–carbon
double and triple bonds was brought to light. The synthetic techniques together
with the newly emerging analytical tools, in particular IR and NMR spectro-
scopy, offered the opportunity to follow the course of a chemical reaction and
thus to understand the mechanism of the process. This also led to the rebirth of
the field of homogeneous catalysis, and it is only fair to say that without the
pioneering work in the 1950s and early 1960s on transition metal organome-
tallics a number of important industrial processes such as the oxidation of
ethene to acetaldehyde by the Wacker reaction, the synthesis of L-Dopa by
the Monsanto process or the stereoselective polymerisation of olefins with the
Brintzinger-type ansa-metallocenes as catalysts would not have been developed.
When I started writing this book, it was exactly 50 years ago that I became
acquainted with organo-transition metal chemistry. As an undergraduate at the
University of Jena in the former Deutsche Demokratische Republik (‘‘East
Germany’’), I attended a course in preparative inorganic chemistry and a junior
colleague of Professor Franz Hein took care of the course. It was at this time,
that Professor Ernst Otto Fischer visited Hein’s laboratory to inform him that,
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xii Preface
based on his work at the Technische Hochschule in Mu¨ nchen, he was convinced
that the unusual ‘‘polyphenylchromium compounds’’, reported by Hein mainly
between 1919 and 1931, were indeed sandwich-type complexes. At first, Hein
was irritated but after his coworkers proved that Fischer’s proposal was correct,
he accepted the new ideas. Since I had the fortune to work for my Diploma
thesis with Hein and for my Ph.D. thesis with Fischer, I became automatically
involved in the rapid and breath-taking development of modern organometallic
chemistry, and I remained caught and fascinated by this subject ever since. The
close personal contacts with Hein and Fischer, together with the fact that from
1968 to 1975 I taught coordination chemistry at the University of Zu¨ rich in the
same building as AlfredWerner did, also awakened my interest in the history of
‘‘my’’ discipline, and it became a challenge to discover the links between the
beginnings in the nineteenth and early twentieth century and our present
research activities.
This book is neither a textbook nor an autobiography. If I take into account
that in recent years organometallic chemistry has not only grown tremendously
but also concerns the chemistry of the majority of the elements of the Periodic
Table, it is nearly impossible to cover the historical development of the whole
field. Therefore, I limited the content to compounds of the transition metals
which also happen to be the most important components in homogeneous
catalysis. I did my best to consider all the relevant literature and I apologize if
I have missed some of the links. It is, of course, a personal view of the discipline
and it may well be that some younger scientists in particular feel that I have
over-emphasized what had happened in the past. Thus, I answer with a sentence
written by the German author Bernhard Schlink in his novel The Reader:
‘‘Doing history means building bridges between the past and the present,
observing both banks of the river, taking an active part on both sides.’’
Wu¨ rzburg, Germany Helmut Werner