ORGLIST: Of sandwiches and Nobel Prizes

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From: Ashutosh (ashujo$##$yahoo.com)
Date: Thu Apr 19 2001 - 04:24:03 EDT


A fascinating story of how R. B. Woodward did not win the Nobel Prize of =
1973, with Geofferey Wilkinson and E. O. Fischer,... and why he should =
have.
Ashutosh

      The Northeastern Section of the American Chemical Society
     
      Of Sandwiches and Nobel Prizes:
     

     
     
       

      Robert Burns Woodward

      By Thomas M . Zydowsky, Worcester, MA*

      The notice in The Times of London (October 24; p. 5) of the award =
of this year's Nobel Prize in Chemistry leaves me no choice but to let =
you know, most respectfully, that you have inadvertently, I am sure =
committed a grave injustice."

      Letter From R.B. Woodward To The Nobel Committee For Chemistry, =
Dated October 26, 1973.

      Ernst O. Fischer and Geoffrey Wilkinson received the 1973 Nobel =
Prize in chemistry for their pioneering work, performed independently, =
on the chemistry of the organometallic sandwich compounds.1 The decision =
to award the Nobel Prize to Fischer and Wilkinson was hardly questioned, =
since it was a fitting tribute to their extensive, groundbreaking =
efforts over the preceding two decades. However, the decision not to =
award a share of the Nobel Prize to Robert Burns Woodward was =
questioned, and even after 25 years, it continues to be a sensitive and =
emotional issue in some circles.2

      Perhaps Woodward himself provided the most emotional and =
historically significant response to the 1973 Nobel Prize. His public =
response varied, but in many situations he said little, if anything, =
about the prize.3 His recently discovered private response, which he =
mailed to the Nobel Committee for Chemistry two days after the winners =
of the 1973 Nobel Prize were announced, reflected his intense desire to =
receive credit for his seminal contributions to organometallic sandwich =
chemistry.4

      We must examine events from 1952 to understand Woodward's reaction =
to the 1973 Nobel Prize in chemistry. In late 1951 and early 1952, two =
independent research groups published papers describing the synthesis of =
an unusually stable iron-containing compound: Kealy and Pauson from =
Duquesne University published a paper entitled A New Type of Organo-Iron =
Compound,5 and Miller, Tebboth, and Tremaine from The British Oxygen =
Company published a paper entitled Dicyclo-pentadienyliron.6

      Kealy and Pauson's paper was submitted to Nature on August 7, =
1951, published in England on December 15, 1951, and arrived in the =
United States about one month later. Miller, Tebboth, and Tremaine's =
paper was submitted to the Journal of the Chemical Society on July =
11,1951, published in England on March 24, 1952, and arrived in the =
United States about four to six weeks later.

      The two papers described the serendipitous synthesis, preliminary =
chemical characterization, and tentative structure assignment for =
dicyclopentadienyliron (see fig. 1). The Duquesne group discovered their =


      [Fig. 1 about here]

      synthesis while trying to prepare dihydrofulvalene from ferric =
chloride and cyclopentadienyl-magnesium bromide, whereas the London =
group uncovered their route during attempts to synthesize amines by =
reacting nitrogen and cyclopentadiene over iron filings. Both groups =
assigned the linear structure shown in Fig. 1 to their unexpected =
product. In doing so, they promptly attracted a contingent of chemists =
who questioned the veracity of the linear structure.

      Harvard colleagues Geoffrey Wilkinson and Robert Burns Woodward =
were part of that contingent. In 1952 Wilkinson was a first-year =
assistant professor of inorganic chemistry, and Woodward was a full =
professor of organic chemistry. Wilkinson (1921-1997) had received his =
Ph.D. in nuclear chemistry from Imperial College of Science and =
Technology in London in 1946, and before his appointment at Harvard, he =
had held postdoctoral fellowships at the University of California at =
Berkeley and at the Massachusetts Institute of Technology (MIT). While =
at MIT, Wilkinson switched from nuclear chemistry to inorganic =
chemistry. Woodward (1917-1979) was already an established star on the =
international chemistry scene in 1952. He had been a child prodigy and =
had received his Ph.D. from MIT at age 20. By 1952, he had already begun =
to publish some of the outstanding work in organic synthesis, structure =
elucidation, and theory that would subsequently earn him numerous =
honors, including the 1965 Nobel Prize in chemistry.

      Myron Rosenblum was a graduate student in Woodward's group in =
1952. He recalled that Woodward came into his lab one day in early =
January 1952 and began to discuss Kealy and Pauson's Nature paper [7]. =
According to Rosenblum, Woodward drew the linear structure for =
dicyclopentadienyliron on a blackboard and said that he thought that it =
was wrong. Woodward then carefully drew the now familiar sandwich =
structure for dicyclopentadienyliron (see Fig. 2) on

      [Fig. 2 about here]

      the same blackboard. Without offering any insight into his =
reasoning, he told Rosenblum: "I think that this is the right structure. =
Why don't you take a few days off from your work and make the compound =
and let's look at it." Rosenblum repeated Kealy and Pauson's synthesis, =
and on January 21, 1952, he had crystals of the bright orange compound =
ready for testing.

      At around the same time, Wilkinson had also come across Kealy and =
Pauson's Nature paper, and he independently thought up the sandwich =
structure for dicyclopentadienyliron [8]. Through a subsequent =
conversation with Rosenblum, Wilkinson learned of Woodward's plan to =
investigate the novel compound. After discussing their mutual interest =
in the problem, Wilkinson and Woodward agreed on a series of experiments =
that would be used to verify their structure proposal.

      On April 2, 1952, less than four months after Kealy and Pauson's =
paper appeared, Wilkinson, Rosenblum, postdoctoral fellow Mark Whiting, =
and Woodward (order of authors on the paper) published a one-page =
communication in the Journal of the American Chemical Society describing =
the results of two experiments that ruled out the linear structure for =
dicyclopentadienyliron [9]. The Harvard group reported that the dipole =
moment of dicyclopentadienyliron was effectively zero and that the =
infrared spectrum showed only one type of C-H bond. In place of the =
linear structure, the Harvard chemists proposed their new structure in =
which the iron atom was sandwiched between two cyclopentadienyl groups, =
hence the name sandwich compounds [10]. The dipole moment and infrared =
data supported the sandwich structure; it is important to emphasize, =
however, that Wilkinson and Woodward dreamed up the sandwich structure =
for dicyclopentadienyliron before any synthetic work or physical =
characterization had even begun.

      Wilkinson and Woodward were not the only chemists to challenge the =
linear structure proposed for dicyclopentadienyliron. William E. Doering =
at Columbia not only questioned it, but in September 1951, he actually =
suggested the sandwich structure to Peter Pauson [11, 12], and, somewhat =
later, John R. Johnson at Cornell also suggested the sandwich structure =
[13]. W. C. Fernelius and E. O. Brimm had their doubts, and at their =
suggestion, Penn State College physicists Ray Pepinsky and Philip Eiland =
determined the molecular structure of dicyclopentadienyliron by using =
X-ray methods [14]. Meanwhile, over in Germany, E. O. Fischer and W. =
Pfab also used X-ray methods to solve the structure. For Fischer, it was =
his first step on the way to the 1973 Nobel Prize in chemistry [15].

      Nothing like the sandwich structure had ever been seen before. In =
1952, Marshall Gates was the assistant editor of the Journal of the =
American Chemical Society, and he handled Woodward's manuscript =
submissions. In a letter to Woodward dated March 28,1952, Gates wrote: =
"We have dispatched your communication to the printers but I cannot help =
feeling that you have been at the hashish again. 'Remarkable' seems a =
pallid word with which to describe this substance" [8].

      Wilkinson and Woodward's "remarkable" structure enticed yet =
another team of chemists to work on organometallic sandwich compounds.

      Jack Dunitz and Leslie Orgel were Research Fellows in England in =
1952, and Dunitz's account of their decision to work on =
dicyclopentadienyliron once again underscores the novelty and lure of =
the sandwich structure. In a 1992 paper celebrating the 40th anniversary =
of the discovery of ferrocene (dicyclopentadienyliron) [17], Dunitz =
said, "I think it is difficult today to appreciate just how surprising, =
unorthodox, even revolutionary, this structure must have appeared to =
chemists forty years ago. At any rate, I have to confess that my first =
reaction was one of extreme skepticism, if not plain disbelief." Dunitz =
came across Wilkinson and Woodward's paper shortly after it appeared, =
and according to Dunitz: "I opened the library copy of the JACS and came =
across this astonishing Harvard proposal: two parallel cyclopentadienyl =
rings with an iron atom sandwiched between them. I thought: what nerve =
these Harvard chemists have! To publicly put forward such a structure on =
such scanty evidence."

      On his way out of the library, Dunitz ran into Orgel, and together =
they scrutinized Wilkinson and Woodward's paper. Orgel was as skeptical =
as Dunitz, so they decided to investigate the new compound. According to =
Dunitz, "We found that the compound was easy to prepare in crystalline =
form. We decided to make it and, by determining its crystal structure, =
demonstrate the incorrectness of the Harvard proposal."

      Dunitz and Orgel soon learned that Wilkinson and Woodward's =
sandwich structure was indeed correct [18]. Their work also provided a =
novel explanation for the stability of this remarkable structure in =
terms of molecular orbital theory.

      Woodward also predicted that dicyclopentadienyliron was aromatic =
and that it would have properties characteristic of typical aromatic =
compounds such as benzene. Later in 1952, a follow-up paper from =
Woodward's group (Woodward, Rosenblum, and Whiting) confirmed the =
predicted aromatic properties of the new compound, and in that paper =
they also proposed the name ferrocene for dicyclopentadienyliron [19]. =
That second communication was Woodward's penultimate paper in the =
ferrocene. series, although his group continued to work on sandwich =
compounds of other transition metals for at least two more years.

      Wilkinson was an assistant professor in search of research topics =
on which to build an independent career. He was undoubtedly aware of the =
significance of the new field that he had helped to create, and he =
recognized the long-term research potential of the sandwich compounds. =
Working independently of Woodward, Wilkinson published four =
ferrocene-related papers in 1952, and many more throughout his career. =
He subsequently became one of the world authorities on the chemistry of =
organometallic sandwich compounds and earned numerous awards for his =
work in that field, including the biggest prize of all-the Nobel Prize.

      During his Nobel Prize award address in Stockholm, Wilkinson =
described the two factors which, in 1952, had led him to propose the =
sandwich structure for ferrocene [20]. The first factor was the =
well-known (to him) instability of transition-metal alkyls and aryls, =
and the second factor was his gut feeling, at that time unproved, =
concerning the binding scheme of several unrelated organometallic =
compounds. In 1951 Wilkinson was already thinking about transition-metal =
complexes of unsaturated ligands (cyclopentadienelike), so he was =
clearly a "prepared mind" waiting for the right chance (ferrocene) to =
come along [21].

      Wilkinson recounted the events leading up to his independent =
proposal of the sandwich structure in a 1975 paper [8]. He described his =
thinking when he came across Kealy and Pauson's Nature, paper during his =
weekly visit to the departmental library in this way:

        On seeing the structure I, which was also the one Miller, =
Tebboth, and Tremaine had drawn in their paper which appeared later, I =
can remember immediately saying to myself "Jesus Christ it can't be =
that!" Now I don't know why it was not the Sedgwick view quoted above =
that first occurred to me but the chelate diene structure, but I =
remember scribbling out on a piece of paper the structure II in which =
both double bonds were coordinated, and almost immediately III, as the =
significance of the resonance structures (I had been much impressed by =
Pauling) dawned, and the equivalence of the carbons became obvious, =
"It's a sandwich." The thing that really excited me was the thought that =
if iron did this, the other transition metals must also form sandwich =
compounds.

      Wilkinson went on to say that he and Woodward independently, and =
for different chemical reasons, proposed the sandwich structure for =
dicyclopentadienyliron, and, over lunch at the Harvard Faculty Club one =
afternoon, they agreed to carry out the experiments needed to verify =
their structure proposal. He also acknowledged that Woodward suggested =
that ferrocene would behave like a typical aromatic compound and that he =
(Wilkinson) had not considered that possibility.

      Woodward was on sabbatical leave in England when the Nobel =
Committee announced the winners of the 1973 Nobel Prize in chemistry. In =
an unpublished letter to the Chairman of the Nobel Committee for =
Chemistry dated October 26, 1973, Woodward reacted to the press release =
for the 1973 Nobel Prize in chemistry in this way [4]:

        The notice in The Times of London (October 24, p. 5) of the =
award of this year's Nobel Prize in Chemistry leaves me no choice but to =
let you know, most respectfully, that you have inadvertently, I am sure =
-- committed a grave injustice.

      Woodward went on to quote several newspaper articles that had =
described Fischer and Wilkinson's contributions to organometallic =
sandwich chemistry, especially their role in the structure elucidation =
of ferrocene. The articles stressed the novelty and significance of the =
exciting new sandwich compounds but never once mentioned Woodward's =
contributions to the ferrocene story.

      Woodward then gave his account of the events leading up to the =
proposal of the correct structure for ferrocene:

        The problem is that there were two seminal ideas in this =
field-first the proposal of the unusual and hitherto unknown sandwich =
structure, and second, the prediction that such structures would display =
unusual, "aromatic" characteristics. Both of these concepts were simply, =
completely, and entirely mine, and mine alone. Indeed, when I, as a =
gesture to a friend and junior colleague interested in organo-metallic =
chemistry, invited Professor Wilkinson to join me and my colleagues in =
the simple experiments which verified my structure proposal, his initial =
reaction to my views was close to derision . . . . But in the event, he =
had second thoughts about his initial scoffing view of my structural =
proposal and its consequences, and all together we published the initial =
seminal communication that was written by me. The decision to place my =
name last in the roster of authors was made, by me alone, again as a =
courtesy to a junior staff colleague of independent status.

      Wilkinson and Woodward gave vastly different accounts of their =
early contributions to organometallic sandwich chemistry. According to =
Wilkinson's 1975 account, he thought up the sandwich structure for =
ferrocene while reading Kealy and Pauson's Nature article, several days =
prior to his conversation with Woodward at the Harvard Faculty Club. He =
regarded himself as a well-trained independent investigator who had =
spent considerable time thinking about the bonding in transition-metal =
complexes and naturally claimed co-inventorship for the sandwich =
structure. He also felt that from the beginning, he and Woodward agreed =
on the new: structure, and that theirs was a collaborative' effort in =
which both parties contributed to the scientific ideas.

      On the other hand, Woodward claimed sole inventorship for both =
ideas (sandwich structure and aromaticity). He recalled that Wilkinson =
initially derided his (Woodward's) sandwich structure proposal but =
eventually embraced the structure and its consequences. Woodward also =
stated that he did Wilkinson a favor by letting him participate in the =
experiments that verified the structure proposal and by putting =
Wilkinson as first author. Wilkinson thought he and Woodward were peers, =
whereas Woodward saw himself as the mentor and Wilkinson as his =
protégé.

      Woodward closed his letter to the Nobel Committee by saying that =
he had not seen the actual award citation issued by the Swedish Academy =
of Sciences or the official press release:

        Regrettably the precise citation issued by The Academy in =
connection with the award is not available to me here in England, nor =
have I been able to find a complete account of the ancillary material =
released to the press. Quite possibly the former does not signalize the =
special importance of the unique structural proposal and the =
demonstration of its correctness, and the latter well make a clear =
acknowledgment--ignored by the press-of my definitive contributions in =
those respects. Should these things be true--though in all candor I have =
to say that the actual press reports here provide no basis for supposing =
that they are--the problem is much minimized. But, I am sure that you =
will understand that I cannot read with equanimity such distorted and =
historically incorrect statements as those quoted above.

      In fact, neither the award citation nor the ancillary material =
released to the press mentioned Woodward by name. In a reply to =
Woodward's letter, Arne Fredga,-then Chairman of the Nobel Committee for =
Chemistry, wrote'[22]:

        Your letter of 26th October was received. It contains =
information not evident from the publications, but of great interest for =
the history of science . . . . The committee does not make available to =
the press information about a newly elected Nobel Laureate . . . . it is =
customary not to mention co-workers and co-authors who are not sharing =
the prize, and this rule has been followed also in the present case.

      Woodward's letter apparently induced at least one member of the =
Nobel Committee to overlook the rule. Acting either on his own or with =
the approval of his colleagues, Professor Ingvar Lindqvist acknowledged =
Woodward's contributions on two separate occasions during his =
introduction of Fischer and Wilkinson at the 1973 Nobel Prize ceremony =
[1]. Lindqvist said:

        The facts were available for all to see. Once the correct =
hypothesis was arrived at, by fantasy or intuition, it readily lent =
itself to simple process of logical deduction. I am of course referring =
to the way in which they, together with the former Nobel Laureate =
Woodward, reached the conclusion that certain compounds could not be =
understood without the introduction of a new concept, namely that of the =
sandwich compounds . . . . This they did by the successful synthesis of =
a large number of compounds which were analogous to the initially =
discovered ferrocene , (named by Woodward in analogy to benzene), but =
with other metals than iron . . . .

      The fact remains that Fischer and Wilkinson received the 1973 =
Nobel Prize in chemistry for their extensive investigations on the =
chemistry of organometallic sandwich compounds, not the discovery. =
Despite having a clear understanding of the importance of the field that =
he helped to establish, Woodward subsequently directed his efforts to =
other areas of organic chemistry. As a result, he missed out on a share =
of the 1973 Nobel Prize-a share that Woodward felt he deserved.

      Woodward's longtime friend and fellow Nobelist Sir Derek Barton =
summarized Woodward's feelings in this way [23]:

        And when Geoff got a Nobel Prize for his work on ferrocene and =
its congeners, which he shared with E. O. Fischer, Bob Woodward said to =
me that it was rather strange, that he deserved to have that Nobel =
Prize. He didn't object to Geoff having one, too. But he certainly =
objected to the fact that he was not on that Prize. And they could have =
done that quite easily, because there was room for another person.

      Roald Hoffmann of Cornell University thinks that Woodward made a =
strategic error by not expanding his organometallic research efforts to =
include other transition metals and instead concentrating on the =
aromatic properties of ferrocene [24]. Myron Rosenblum of Brandeis =
University feels that Woodward left the field because "perhaps he was =
more interested in the art and intellectual drama of organic synthesis" =
[25].

      In retrospect, it is hard- to second-guess Woodward's decision to =
concentrate on organic synthesis, structure elucidation, and theory. =
While Fischer and Wilkinson conducted their Nobel Prize-winning research =
in organometallic chemistry, Woodward received the 1965 Nobel Prize in =
chemistry for his contributions to the "art of organic synthesis," =
developed the Woodward-Hoffmann rules for the conservation of orbital =
symmetry with Roald Hoffmann, and together with Albert Eschenmoser, led =
the team of chemists that completed the 100-step total synthesis of =
vitamin B12.

      The Nobel Foundation's official record regarding the 1973 Nobel =
Prize in chemistry is closed to the public until 2023; however, a letter =
from then Nobel Chemistry Committee Chairman Holger Erdtman to =
Woodward's good friend and fellow Nobel laureate Lord Todd offers an =
unofficial explanation for the Nobel Committee's decision not to include =
Woodward in the 1973 Nobel Prize [26]. This letter, dated December =
13,1973, states:

        Thank you for your confidential letter of Nov. 30, from which I =
understand that Bob was distinctly upset--and perhaps not =
unreasonably--by the press reports of the award. However, I feel that =
the name Woodward has come a little out-of-the-way (if you understand =
that dictionary expression!). In the final declaration to the Academy =
it. is said that Woodward made a point contribution of value (of certain =
importance).

      Geoffrey Wilkinson and Robert Burns Woodward left a rich chemical =
legacy upon which future generations of chemists will continue to build. =
They also left a story, albeit an incomplete and irresolvable one, which =
speaks to the emotions of the people behind the scientific advances and =
discoveries.

      Acknowledgments

      I want to thank Ed Atkinson, Derek Barton, Michael Becker, Mary =
Ellen Bowden, F. A. Cotton, Jack Dunitz, Dick Hill, Roald Hoffmann, Gail =
McMeekin, Myron Rosenblum, Leslie Orgel, Linda Simon, Leo Slater, Arnold =
Thackray, Lise Wilkinson, Crystal Woodward, Eudoxia Woodward, Marcia =
Yudkin, and members of the Harvard University Archives staff for their =
help and support during various phases of this work.

      References and Notes

      1. Lindqvist, I. In Nobel Lectures in Chemistry 1971-1980, =
Frangsmyr, T., and Forsen, S., Eds.; World Scientific: Singapore, 1993; =
pp 99-100.

      2. This is my personal observation based on interviews with some =
of Woodward's former co-workers.

      3. One unsubstantiated exception involves Woodward and a prominent =
English chemist.

      4. HUG(FP) 68.10, Box 25, Nobel Prize II (folder 2). "By =
permission of the Harvard University Archives."

      5. Kealy, T. J.; Pauson, P. L. Nature 1951, 168,1039-1040.

      6. Miller, S: A.; Tebboth, J. A.; Tremaine, J. F. J Chem. Soc. =
(London) 1952, 632-635.

      7. Professor Myron Rosenblum, tape-recorded interview with Tom =
Zydowsky, Waltham, MA, August 28,1997.

      8. Wilkinson, G. J Organometal. Chem. 1975, 100, 273-278.

      9. Wilkinson, G.; Rosenblum, M.; Whiting, M. C.; Woodward, R. B. =
J. Am. Chem. Soc.1952, 74, 2123-2124.

      10. Geoffrey Wilkinson used the term "sandwich" in a 1952 paper =
(Wilkinson, G. J Am. Chem. Soc.1952, 74, 6148-49). Jack Dunitz and =
Leslie Orgel used the term "molecular sandwich" in their 1953 Nature =
paper (see Ref. 18, below) that they submitted three weeks after =
Wilkinson's.

      11. See footnote 41 in Pauson, P. L. Quart. Rev. 1955, 391-414.

      12. I want to thank Professor Roald Hoffmann for bringing this =
reference to my attention.

      13. HUG(FP) 68.10, Box 13, Correspondence-Personal, 1950-1953, "By =
permission of the Harvard University Archives."

      14. Eiland, P. F.; Pepinsky, R. J Am. Chem. Soc.1952, 74, 4971.

      15. Fischer, E. 0.; Pfab, W. Z. Naturforsch.1952, 76, 377-379.

      16: HUG(FP) 68.8, Box 13; Ferrocene (folder 1), "By permission of =
the Harvard University Archives."

      17. Dunitz, J. In Organic Chemistry: Its Language and Its State of =
the Art,- Kisakürek, M. V., Ed.; Verlag Helvetica Chimica Acta: Basel; =
VCH: Weinheim, New York, 1993; pp 9-23.

      18. Dunitz, J. D.; Orgel, L. E. Nature 1953, 171,121-124.

      19. Woodward, R. B.; Rosenblum, M.; Whiting, M. C. J Am. Chem. =
Soc.1952, 74, 3458-3459.

      20. Wilkinson, G. In Nobel Lectures in Chemistry 1971-1980; =
Frangsmyr, T., and Forsen, S., Eds.; World Scientific: Singapore, 1993; =
pp 137-154.

      21. Seyferth, D.; Davison, A. Science 1973, 168, 699-701.

      22. HUG(FP) 68.10, Box 25, Nobel Prize II (folder 2), "By =
permission of the Harvard University Archives."

      23. Professor Derek Barton, tape-recorded interview with Tom =
Zydowsky, College Station, TX, November 22,1997.

      24. Professor Roald Hoffmann, tape-recorded interview with Tom =
Zydowsky, Ithaca, NY, May 14,1998.

      25. Professor Myron Rosenblum, personal communication to Tom =
Zydowsky, December 20,1998.

      26. HUG(FP) 68.10, Box 25, Nobel Prize II (folder 2), "By =
permission of the Harvard University Archives:"

       

      TOM ZYDOWSKY is an organic chemist and writer living in Worcester, =
Massachusetts. He received a Ph.D. (organic chemistry) at the University =
of Georgia with R.K. Hill.

      He is writing a series of articles on Woddward that will form a =
basis for a full biography. Anyone interested in contributing to the =
biography may contact Tom at 25 Harley Drive #6, Worcester, MA 01606 or =
at tmzinc$##$aol.com.


     

     

     

     
       

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