PDF《Pure Appl. Chem., Vol. 73, No. 2,》

Pure Appl.

Chem., Vol. 73, No. 2, pp. 209C220, 2001. ?

2001 IUPAC

209 Organometallic chemistry at the threshold of a new millennium. Retrospect and prospect* Jack Halpern Department of Chemistry, The University of Chicago,

5735 S. Ellis Avenue, Chicago, IL 60637, USA Abstract: The evolution of organometallic chemistry during the second half of the 20th cen- tury has transformed chemical science and technology to a degree and in ways that have rarely been matched throughout the history of chemistry. These include the discovery of rad- ically new types of chemical compounds;

novel structures and bonding modes;

unprecedent- ed reactivity patterns;

unsuspected roles of organometallic chemistry in biology;

powerful new synthetic methodologies;

new materials;

and whole new classes of catalysts and catalyt- ic processes of extraordinary versatility and selectivity. The impact of these developments, which still are unfolding, has been truly revolutionary. Some milestones in this remarkable chapter of chemical history, as well as challenges and opportunities confronting organometal- lic chemistry today, will be examined. INTRODUCTION The remarkable flowering of organometallic chemistry, notably of the transition metals, during the sec- ond half of the 20th century, has enriched and transformed chemical science to a degree and in ways that have few parallels in the history of the discipline. The full dimensions of this development cannot be easy to appreciate for anyone who was not around to witness the entire period. In 1950, the traditional branches of chemistry―physical, organic, and inorganic―already were mature disciplines, indeed, to the point that prompted many to wonder whether chemistry had already reached its full maturity with no really major new insights or discover- ies remaining to be uncovered. At the time, organometallic chemistry was a fledgling discipline―hardly recognizable as such. A striking reminder of the state of the field is provided by the organometallic literature―or lack thereof―of the period. Confronted with the massive current volume of literature on organometallic chemistry―journals, monographs, national and international conferences such as this one―it is hard to believe that a general monograph on organometallic chemistry―G. E. Coates'

Organometallic Compounds―published in 1956, professed to cover the subject in less than

200 pages, of which fewer than

25 were devoted to the organometallic chemistry of the transition metals [1]. The ensuing growth of the field―and of the organometallic literature―were dramatic. Updated and expanded editions of Coates'

monograph followed in rapid succession, a 360-page second edition in

1960 [2], and a two-vol- ume 950-page third edition, co-authored by M. L. H. Green, P. Powell, and K. Wade, in

1971 [3]. The

1982 monograph Comprehensive Organometallic Chemistry, edited by G. Wilkinson, spans nine vol- umes occupying ca

9400 pages [4], and the

1994 supplement, covering the literature for

1982 to 1994, fills an additional

14 volumes and

9000 pages [5]. At the same time, the fraction of space devoted to *Lecture presented at the XIXth International Conference on Organometallic Chemistry (XIX ICOMC), Shanghai, China, 23C28 July 2000. Other presentations are published in this issue, pp. 205C376. the organometallic chemistry of the transition metals increased dramatically from 14% in the first edi- tion of Coates [1] to 68% in Wilkinson'

s compendium [4]. HISTORICAL PERSPECTIVE Some perspective on the extraordinarily rich landscape of discovery that characterized this period of explosive growth of organometallic chemistry is provided by the, admittedly incomplete and somewhat arbitrary, chronology of selected landmark advances in Table 1. Although the organometallic chemistry of the main group elements also has experienced impor- tant advances, much of the focus of the modern era of organometallic chemistry―both conceptual and in terms of applications―has been on the transition metals, and it is with this branch of organometal- lic chemistry that the present account, and the entries in Table 1, are primarily concerned. The early decades represented in Table 1, through about 1970, are characterized by three types of discoveries [6]. J. HALPERN ?