Whose idea was it?

ITHACA, N.Y. -- Roald Hoffmann was fixing his bicycle in the garage on the morning of Oct. 19, 1981, when he heard on the radio that he had won the Nobel Prize in chemistry. He ran into the house to call his mother. ''I was lucky," he said. "I got to the phone before it started ringing."

Over the next weeks, Hoffmann was inundated: Phone calls and notes piled up at his Cornell University office, including a letter from Elias J. Corey, a colleague from his days at Harvard.

''Congratulations!" the letter began, before going on to state that Corey had come up with the original idea behind the set of rules for which Hoffmann won the prize -- rules that gave scientists the power to predict how certain chemical reactions would proceed.

Corey wrote that Hoffmann's scientific partner, the eminent and deceased chemist, Robert B. Woodward, stole the idea from him after a private conversation in 1964.

''In a manner of which few would be capable he pirated the idea," Corey wrote, asking that Hoffmann correct the historical record in his Nobel speech.

The request shocked and upset Hoffmann, he said during a recent interview at his Cornell office. With Woodward dead, ''How could he expect that I would tell the world of his claim?"

Hoffmann kept silent about Corey's claim when he accepted the award in Stockholm in December 1981.

But now, after their conflict has simmered in relative obscurity for decades, both scientists have spoken publicly about it for the first time, offering a rare glimpse of the human drama behind elite science, and insight into the tricky business of giving credit for a discovery.

Disputes over the origin of ideas rarely become public, but scientists and historians agree that, because of the complexity of science, discoveries often have a twisted lineage and recognition may be unintentionally, or intentionally, mislaid.

Even when there is clear evidence of a person's contribution -- in published journal articles or lab notebooks -- controversy has erupted. James Watson and Francis Crick drew on Rosalind Franklin's work when they described the double-helix structure of DNA, but many think her role was downplayed. Dr. Raymond Damadian took out a full-page ad in The New York Times when he was not included in the 2003 Nobel Prize for medicine, protesting that he had done the basic groundwork leading to development of magnetic resonance imaging and that the winners had merely refined his ideas.

Ideas can be even harder to trace to their source. Scientists can independently reach the same breakthrough, a colleague's offhand comment can lead to insight, or, as Corey alleged to Hoffmann, an idea can be stolen outright.

''How does one decide whether or not a claim is true or not: People discuss things all the time at scientific meetings, in hallways. . . . You don't really know what happens," said Michael Kalichman, director of the research ethics program at the University of California at San Diego.

Competition, rivalry, and ego often help drive scientists, and these elements figure in to the Corey-Woodward-Hoffmann dispute. But the case is also unusual and surprising: Four decades have passed, and the players are scientific giants. All won Nobel Prizes -- Woodward's came in 1965, Corey's in 1990.

The two living chemists have little to gain from the controversy at this point, but Corey has never dropped his claim, taking it public last year in a speech accepting another prize. In listing his accomplishments, he said he proposed the idea for the rules -- and created a stir in the normally sedate chemistry community.

''It is very strange," said William von Eggers Doering, an 87-year-old professor emeritus in Harvard's chemistry department who was Woodward's friend. ''But,on the other hand, the personalities that go with distinguished basic scientific achievement really vary all over the lot. . . . If a scientist is any good at all, you just have to accept the nonsense that goes with it."

Chronology of an ideaIn May 1964, Harvard's chemistry department was home to a host of smart young scientists, presided over by a handful of superstars including Woodward -- a flamboyant, uncompromising genius who always dressed in blue, and even had his parking space painted blue. In the basement of Converse Hall, Corey, appointed a full professor at Harvard four years earlier, was embarking on a brilliant career. Just down the hall sat Hoffmann, a 26-year-old theoretical chemist who frequently stopped into Corey's office to learn organic chemistry.

Corey has a clear memory of the events of that month, which he says disturbed him greatly -- and the following account was drawn from a series of letters he wrote to Hoffmann in the 1980s and a recent interview in his Harvard office.

Corey, then 35, was working into the evening on Monday, May 4, as he and the other driven chemists often did. At about 8:30 p.m., he dropped by Woodward's office, and Woodward posed a question about how to predict the type of ring a chain of atoms would form. After some discussion, Corey proposed that the configuration of electrons governed the course of the reaction. Woodward insisted the solution wouldn't work, but Corey left drawings in the office, sure that he was on to something.

''I felt that this was going to be a really interesting development and was looking forward to some sort of joint undertaking," he wrote.

But the next day, Woodward flew into Corey's office as he and a colleague were leaving for lunch and presented Corey's idea as his own -- and then left. Corey was stunned.

Two days later, Woodward introduced the idea at a group meeting, Corey said.

Hoffmann said he learned of the idea from a colleague who attended the meeting and offered his skills as a theoretical chemist to Woodward, whose expertise lay in other areas.

Hoffmann stopped by the next week to tell Corey off his collaboration with Woodward. Corey remembers telling Hoffmann then that he had proposed the fundamental idea to Woodward -- and that Hoffmann looked uncomfortable and fled.

''I remember no such thing," Hoffmann said in the recent interview. He recalled, however, that Corey talked to him during that period as if Corey had played an essential role in the story.

Hoffmann was curious enough about the role Corey might have played to ask Woodward whether Corey would be cited anywhere in the publication of the first paper on the rules. He remembers a simple, unemotional ''no" and never pressed his colleague further.

As a 26-year-old postdoctoral fellow, he said, it was not his place to interrogate the 47-year-old Woodward -- a senior colleague he respected and trusted.

Other scientists who knew Woodward said the man's larger-than-life personality -- a prodigious smoker, drinker, and thinker whose ambition ran so high that he wrote the Nobel committee in later life requesting a second prize -- might also have been a barrier to confrontation.

''Bob went through the world looking at most persons, as he described it, as dim bulbs," Doering said. ''He wasn't your English sheepdog by any means . . . and I think this is one reason this all begins to come out after his death. [Corey] wouldn't dare say it while he was alive."

Science superstarsThe publication of five papers in 1965 unveiled the Woodward-Hoffmann rules, introducing some order and predictability first to one specific reaction and then to the larger world of organic chemistry. Using quantum mechanics, chemists could understand the interactions and shapes of their molecules, making it easier to design molecules -- and drugs.

Corey's and Hoffmann's paths diverged, although they maintained a friendly correspondence over the years.

The rules elevated Hoffmann into the top ranks of chemists, and even as the papers were being published, he left Harvard for a position at Cornell -- where he remains today. A Renaissance man, he has written plays and poetry and hosted a chemistry TV series amid his work in theoretical chemistry.

Corey became a superstar of synthetic chemistry. He developed new ways to mimic and construct complex molecules, a passion reflected in his office -- a kind of scientific playground where models of molecules dangle from the walls. Corey has published more than 1,000 scientific papers in his career; his work has been cited more than that of any other chemist in history, according to a survey done by the Journal of the American Chemical Society three years ago.

During the late 1960s and 1970s, Corey occasionally discussed his claim with close colleagues at Harvard, but never said anything to Woodward before his death in 1979. ''Woodward would not have backed down, having presented the idea as his own," Corey said in an interview, also citing a desire to avoid a fight that could sully Harvard or its top-notch chemistry department.

When Corey visited Cornell to attend a symposium in the 1970s, Hoffmann recalled, Corey said that he ''made" Hoffmann's career -- a statement that Hoffmann took as a joke.

It was not until the 1981 Nobel Prize was announced that Hoffmann said he learned of the details that had rankled Corey all these years.

Days after Corey's first letter arrived, Hoffmann wrote a sympathetic but firm reply. ''There is no way that I can or will pass judgment on what transpired between you and Bob. It would be unfair to one of the protagonists, who is dead."

In Corey's next letter, dated a week later, his tone turned harsher. ''You cannot deny that despite the possibility of appalling dishonesty at the roots of your collaboration with Bob, you elected to close your mind," Corey wrote, accusing Hoffmann of ''stonewalling" and reminding him that history would judge him.

''The second letter was not hurtful, but offensive . . . a sort of heightening of the claim and an accusation of dishonesty," Hoffmann said. Bucking Nobel tradition, Hoffmann decided not to tell the story of his discovery in his Nobel speech, but talked about new work. He recognized Corey as a valuable teacher, without mentioning Corey's claim.

The two met again in 1984, and discussed the incident for hours in Corey's office, hoping to set the record straight.

Both scientists attempted to uncover the truth, questioning colleagues who were at Harvard in 1964 and searching through records and notes from the time, but they have been unable to resolve their differences. Hoffmann acknowledged his memory is very rough, and details of his account have wavered over the years, while Corey's very acute recollections have remained firm.

Claim becomes publicCorey's claim languished until early last year, when he said in a speech that was published in the American Chemical Society's trade magazine that, ''On May 4, 1964, I suggested to my colleague R.B. Woodward a simple explanation . . . that provided the basis for the further development of these ideas into what became known as the Woodward-Hoffmann rules."

That simple sentence, dropped into a much longer speech upon receiving the Priestley medal, reverberated.

''The audience/readership was astounded: Were the Woodward-Hoffmann rules not formulated by Woodward and Hoffmann at all? Should they rather be called the Corey-Woodward-Hoffmann rules?" Peter Gölitz wrote in an editor's note in the international chemistry journal, Angewandte Chemie, which thrust the issue further into the spotlight when it published an unusual five-page response from Hoffmann. A secretary for Angewandte Chemie said it had received a large response to the paper.

A debate ensued about whether Corey was right, why he chose to press his claim so late, and whether Hoffmann's response was appropriate.

Douglas Applequist, the colleague who was in Corey's office when Woodward first presented the idea as his own on May 5, 1964, said he couldn't recall exactly who said what 40 years ago. Now an emeritus professor at the University of Illinois, Applequist recalled, ''I knew [Corey] was interested in the subject when I was at Harvard in 1964, and I was surprised therefore when, the first publications after that, his name wasn't on them."

Other colleagues, who already knew about Corey's claim to the Woodward-Hoffmann rules, were dismayed. ''My basic and most important reaction is -- I'm sorry Corey's brought it up, which is to say whatever happens, it doesn't do anybody good to hear these remarks, Corey included," said Ian Fleming, a British chemist who was at Harvard when the rules were being developed.

Scientists interviewed widely believed that Corey was telling the truth, but some said that Woodward had a habit of posing questions to which he knew the answer, meaning he could have already devised a solution when he asked Corey about ring formation.

Truth is likely to remain elusive. The only other witness to the conversation -- Woodward -- said in a 1973 lecture that the idea came to him in a ''crucial flash of enlightenment . . . out of the blue."

Corey said that he never intended to start a firestorm -- and he asked the Globe not to publish this article or use his letters. ''When I made my Priestley statement, it was so the historical record would be correct. [The idea] was one of my scientific contributions. I don't care for recognition or award."

Hoffmann, for his part, said that he does not believe Corey, but if hard evidence were offered, he would apologize and give him credit for the ''seminal idea."

As an appropriate twist on a story in which truth, perception, and creativity are already tangled -- making it impossible to know who had the thought first -- the idea already existed. In 1961, Dutch scientist L.J. Oosterhoff proposed something similar to the one Corey describes making, said Jerome Berson, a Yale chemist who wrote a book on the Woodward-Hoffmann rules.

''I think it's fair to say that if Corey did give Woodward the idea, and that is the crux of it, then Corey himself was anticipated."

Carolyn Y. Johnson can be reached at cjohnson@globe.com.