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Single-molecule magnet controversy highlights transparency problems

Nov. 2018/11/6 14:59:14 By LEAP Chem

For Conrad A. P. Goodwin, June 6, 2017, was a pretty harrowing day.


The organometallic chemist, then at the University of Manchester, had just finished his Ph.D. on a high. Earlier that year he had synthesized an organometallic complex called dysprosocenium that could be switched from one stable magnetic state to another. Single-molecule magnets (SMMs) like this might eventually be used in extremely-high-density memory devices, but researchers had previously been able to make SMMs that only operated at ultracold temperatures. Crucially, Goodwin’s molecule could retain its designated magnetic state at up to 60 K—the highest temperature yet for any SMM. By the end of May, Nature had accepted a paper about the work from Goodwin and his colleagues, subject to revisions.


Then, on that fateful June day—months before Goodwin’s report actually published—a paper appeared in Angewandte Chemie describing exactly the same molecule, made in exactly the same way. Goodwin and his colleagues had been scooped. To make matters worse, the team behind the Angewandte paper was led by Richard A. Layfield, a professor whose office was just down the hall from Goodwin’s supervisor, David P. Mills.


“We’d put so much work into it,” recalls Goodwin, who now works at Los Alamos National Laboratory. “The synthetic methodology was brand new, so we thought we were on to something cool. Then, suddenly, the novelty was gone.”


This highly unusual situation, two groups at the same university working on the same project independently, sparked a complaint to the university, which subsequently convened a panel to investigate what happened.


The panel reached its verdict on Jan. 8, 2018. But it took another eight months before the university made any public statement on the matter. Released on Sept. 5, the brief statement on Manchester’s website says that the investigation “reached a finding of research misconduct against a senior academic who is no longer in the employment of the University.” That senior academic, the university confirmed to C&EN, was Layfield, who moved to the University of Sussex in May 2018.


Manchester’s statement prompted questions. Research misconduct comes in many forms, from lapses in judgment to outright falsification of results. But what exactly was Layfield accused of? What evidence supported the finding of research misconduct? And did Sussex know about all this before it hired Layfield?


Until now, the answers have been shrouded in mystery. That’s because both Manchester and Sussex have refused to publicly release any further information and have recommended that employees do not discuss details of the case with C&EN. They argue that misconduct investigations are confidential and that they have data protection and other legal obligations that may prevent public disclosure.


“As a young researcher, the way things have been swept under the rug is quite upsetting,” Goodwin says.


Under the U.K.’s Freedom of Information Act, C&EN requested a copy of Manchester’s investigation report and received a partially redacted version. Although people’s names have been blacked out, information from researchers familiar with the case (who requested anonymity out of concern for the potential impact on their careers) helped fill those gaps.


Taken together, these sources reveal how Layfield learned of the Mills group’s intention to make dysprosocenium and then raced to publish the synthesis first. The investigation found no problems with his scientific data or the paper’s conclusions. But it did determine that Layfield had presented his work—without disclosing the rival group’s discoveries—in an “unethical” way that “amounts to deception,” according to the report.


When C&EN put the allegations in this article to Layfield, he provided a brief statement: “At the time of reporting my group’s findings, I understood them to be novel.” There is no evidence that Layfield has ever been involved in any other instances of research misconduct.


Research integrity experts say that the air of secrecy around this case illustrates a wider problem with the way U.K. universities investigate allegations of research misconduct. All too often, there is a lack of transparency about how institutions run such investigations, and their findings often remain confidential. And although Manchester did belatedly issue a public notice that it had concluded an investigation, some universities do not even disclose that such investigations have taken place.


“Most U.K. universities seem to regard any kind of investigation as confidential,” says Elizabeth Wager, a consultant on publication ethics and former chair of the Committee on Publication Ethics (COPE).


Many argue that a lack of transparency risks undermining public trust in research and may also hamper science itself. “The community of scholars works on trust,” says C. K. Gunsalus, director of the National Center for Professional & Research Ethics at the University of Illinois, Urbana-Champaign. “When that trust is broken, it’s incumbent on the institution to share the facts so that other scholars do not waste time, energy, and resources.”


“We do not accept that we have not been transparent,” the University of Manchester says in a statement to C&EN. “The University has a duty of care to its staff and students and must take this into account when deciding whether to disclose information which identifies or may identify individuals.” It also notes that it informed Angewandte Chemie and funders affected by the case.


But the chorus of voices crying for reform of the U.K.’s research integrity system is growing louder. In July, members of Parliament (MPs) on the U.K.’s House of Commons’ Science & Technology Committee concluded an inquiry into research integrity issues and determined that some U.K. universities were being too secretive about their misconduct investigations. The MPs called for a national committee on research integrity, a watchdog group that would ensure research misconduct investigations are handled rigorously and transparently. “When someone is found guilty of misconduct, it’s hard to see any circumstances where keeping that secret is appropriate,” argues Norman Lamb, MP, the committee’s chair and a former employment lawyer.

If publication is the coin of the realm in academia, then a paper that takes credit for someone else’s research is a serious matter.

C. K. Gunsalus, director of the National Center for Professional & Research Ethics at the University of Illinois, Urbana-Champaign

Cool switch


The two labs involved in the dysprosocenium case are targeting SMMs because such molecules could offer a way to dramatically shrink data-storage systems. These molecules can exist in two different magnetic states that represent a one or zero in terms of binary data; an external magnetic field can “write” this data by switching the molecule from one state to the other. Mills’s team estimates that arrays of these molecules could hold up to 30 terabits of data per square centimeter—hundreds of times as much as the best commercial magnetic hard drives—as long as the molecules remain in a given magnetic state at practical temperatures.


The dysprosocenium complex made by the Manchester researchers, [Dy(Cpttt)2][B(C6F5)4], contains a Dy3+ ion sandwiched between two cyclopentadienyl ligands that each sport three tert-butyl groups (Cpttt). The metal ion has five unpaired electrons with a lot of orbital angular momentum, which helps ensure that the complex’s data-storing states are distinct. The ligands shape the energies of the complex’s magnetic states to prevent a binary “one” from spontaneously turning into a “zero,” which would erase the data in this molecular memory.


Before dysprosocenium arrived on the scene, the best SMMs would lose their memory above 14 K or so because of molecular vibrations. So achieving this effect at 60 K was a major advance in the field. The compound also operated tantalizingly close to the temperature of liquid nitrogen (77 K), which would make memory devices based on SMMs a much more realistic prospect—not for desktop computers, but perhaps in large data centers. “Liquid nitrogen is cheap and plentiful, so getting it to liquid-nitrogen temperature would make this technology accessible for applications in industry,” says Nicholas Chilton of the University of Manchester, who worked with Mills and Goodwin on the Nature paper.


Chilton had calculated that a Dy3+ complex bearing just two ligands, one on either side of the metal ion, might have the right properties to set a new temperature record. Goodwin was tasked with making it a reality, working with lab colleague Fabrizio Ortu.


The Cpttt ligand was important because it gave the complex a rigidity that helped preserve its magnetic memory. But the key to the researchers’ synthesis was an esoteric silylium reagent that could remove chloride from a precursor complex, Dy(Cpttt)2Cl, and replace it with a bulky anion, tetrakis(pentafluorophenyl)borate [B(C6F5)4]–, which coordinates only weakly with the complex and doesn’t disturb its magnetic states.


By mid-February 2017, Goodwin says, they had made the chloride precursor and were ready for the final push.


Meanwhile, Layfield had been working with dysprosium metallocenes for years. A 2016 paper that he coauthored with Chilton notes that a Dy3+ ion sandwiched by two cyclopentadienyl ligands could have impressive magnetic properties. However, the paper also says that preparing such a highly electrophilic complex presented “a formidable challenge” (Angew. Chem. Int. Ed. 2016, DOI: 10.1002/anie.201604346). Layfield instead pursued related complexes with more ligands, which were easier to synthesize.


The report produced by Manchester’s investigation panel details how the two labs subsequently converged on dysprosocenium.


On Feb. 24, 2017, Mills told Layfield that his team was preparing to make a dysprosocenium complex but did not disclose how. The report alleges that this conversation prompted Layfield to work toward the same complex, a point that would become crucial to the investigation panel’s ruling. On the same day, Layfield emailed another researcher and asked that person to suggest a chloride-removing reagent that could be used to make a dysprosocenium complex, according to the report.

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Mills’s team synthesized its dysprosocenium and obtained a crystal structure in early March 2017. By the end of the month, the researchers had written a draft paper on the work. They deposited the compound’s crystal structure in the Cambridge Crystallographic Data Centre’s freely-accessible database on April 7, 2017, and submitted their paper to Science on the same day. A few days later, Layfield learned that Mills and coauthors had made dysprosocenium and that they had submitted their paper. The report alleges that this spurred Layfield to hasten his own team’s experiments toward the molecule.


According to Goodwin, on April 18, 2017, Science declined to send his team’s paper out for peer review, so the group submitted it to Nature a few days later.


The report says that researchers in Layfield’s group finally made the Dy(Cpttt)2Cl precursor in early May. Dysprosocenium itself soon followed, and after working on magnetic measurements and theoretical calculations with collaborators in China and Finland, Layfield’s group added its own structure of the complex to the Cambridge crystallography database on May 23, 2017. Angewandte Chemie received Layfield’s paper on May 26—the very same day that Mills’s Nature paper was accepted, subject to revisions, according to the report.


Layfield’s paper was peer reviewed, accepted, and then published just over a week later (Angew. Chem. Int. Ed. 2017, DOI: 10.1002/anie.201705426). Layfield used the same silylium reagent that Mills’s team used to make dysprosocenium and paired the complex with the same weakly coordinating anion. “The molecule is identical; the magnetic experiments are more or less identical; the results are identical,” says Chilton, who agreed to speak to C&EN about the scientific content of the two dysprosocenium papers but not the misconduct case.


Chilton and Mills’s Nature paper was finally accepted on June 27, 2017, and eventually published on Aug. 23 (Nature 2017, DOI: 10.1038/nature23447). Since then, Layfield’s paper has been cited more than 130 times and the Nature paper more than 240 times.


As the Manchester report says, competition between research groups does not amount to poor practice or research misconduct. The report also notes that Layfield did not get the idea to use the silylium reagent from Mills or his group, nor did he steal their data.


Nevertheless, the investigation panel concluded that Layfield had committed two forms of research misconduct. First, it alleges that Layfield was fully aware that Mills’s team had submitted its paper before his own group made the molecule. This was done “in the knowledge that it contained essentially the same research” as Mills’s paper and with the intention of beating Mills to publication in order to obtain the credit for the discovery. “This, in the Panel’s view, was unprofessional and unethical conduct,” the report says.


“If publication is the coin of the realm in academia, then a paper that takes credit for someone else’s research is a serious matter,” says the ethics expert Gunsalus, of the University of Illinois. According to the report, Layfield said he was unaware of the actual contents of Mills’s paper. Layfield still asserts that he believed his findings to be novel.


Second, Angewandte Chemie’s guidelines for authors state that they “must inform the editor of other manuscripts accepted, submitted, or soon to be submitted that have a bearing on the manuscript being submitted.” But the report alleges that Layfield did not mention Mills’s paper, which was pending with Nature, when he submitted to Angewandte.


The report says that Layfield’s failure to provide this information to the journal, “in the Panel’s view, amounts to deception.” The findings in Layfield’s manuscript “were being presented as entirely novel findings to the journal” even though he “was aware that another research group was the first to make the discovery and had already submitted a manuscript describing this work.”


C&EN found no evidence that Layfield’s coauthors were involved in these alleged instances of misconduct. C&EN approached his coauthors for interview but received no responses.


In the report, the investigation panel writes that it was concerned that Layfield “appeared to have no insight as to the damage caused by his actions on the University, his colleagues’ or his own reputation; nor did he show any understanding of wrong doing, even in hindsight.” To address this, the report recommended that Layfield should undertake research integrity training and receive appropriate mentoring. That did not happen at Manchester, the university says, because he left soon after the investigation ended; it is unclear whether training or mentoring happened at Sussex. The reasons for Layfield’s move to Sussex are also unknown. Sussex would not comment on whether it knew about the misconduct case before hiring Layfield.


In a statement to C&EN, Sussex said, “The University supports Professor Layfield and the important work he is carrying out at Sussex. In his short time at the University, he has shown a commitment to the highest standards of research integrity and is a valued member of faculty.”


The investigation was a bruising experience for all concerned. “Everybody has been upset about what has happened,” says Richard Winpenny, who was head of chemistry at the University of Manchester during the investigation. “I’ve lost more sleep over this than anything else I’ve dealt with.”


Layfield and two of his coauthors offered their own account of how they arrived at dysprosocenium in an article published on Aug. 9, 2018, which states that they had been working toward it since 2010 (Acc. Chem. Res. 2018, DOI: 10.1021/acs.accounts.8b00270). But by the time the account was published, rumors were flying around the small community of SMM researchers. Things came to a head at the 10th International Conference on f-Elements, held Sept. 3–6, 2018, in Lausanne, Switzerland, which Mills and Layfield both attended. With the conference underway, gossip about the controversy finally prompted Manchester to issue its online statement about the investigation.


Source: ACS