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Chemists retract 15-year-old paper and publish a revised version

After discovering they misidentified the molecule central to the study, researchers carry out a structural do over

by Stephen K. Ritter
September 7, 2017 | A version of this story appeared in Volume 95, Issue 36

A pair of structures shows a wrongly identified macrocyclic azaphosphinate ligand and the actual smaller ligand.

In what is being called an honest mistake, a research group has reported that the structure of the headline compound from a paper it published in 2002 is incorrect. To set the record straight, the team has retracted the paper and at the same time published a new paper reporting the actual structure.

This strategy offers chemists a palatable way to correct the literature when a pervasive error is found and the error is not the result of any ethical misconduct. Other journals, such as the Journal of the American Medical Association, have handled similar situations by retracting and replacing papers, making the original versions available in supporting information sections with errors highlighted.

The original paper published by medicinal inorganic chemist Chris Orvig and his group at the University of British Columbia reported the synthesis of a new tetraazamacrocycle ligand (Inorg. Chem. 2002, DOI: 10.1021/ic010716a). The researchers made the compound to see how replacing two methylene groups in a macrocyclic ring with phosphinate groups affected the stability of complexes formed with lanthanide ions. Such complexes are of interest as contrast agents for magnetic resonance imaging.

Orvig says all the characterization data were consistent with the ligand having a dimeric structure. But the team had a hard time growing crystals of the ligand and couldn’t confirm its structure by X-ray analysis. When graduate student David M. Weekes was recently revisiting the ligand for a new project, he was able to get a crystal structure and found the data didn’t add up, literally. Weekes discovered the molecule is half the size expected—it is monomeric, not dimeric—and forms a 2:1 complex with lanthanides instead of a 1:1 complex as originally thought.

An incorrect structure might normally be handled by issuing a correction statement appended to the paper pointing out the error. But in this case, Orvig says, the incorrect assumption of the ligand structure nullified the conclusions. Orvig and the journal’s editors agreed the best solution would be to retract the paper (Inorg. Chem. 2017, DOI: 10.1021/acs.inorgchem.7b01932). But they also agreed that Orvig’s group could publish a new paper along with the retraction reporting the correct structure (Inorg. Chem. 2017, DOI: 10.1021/acs.inorgchem.7b01117). The event was first reported by Retraction Watch, a blog that aims to increase the visibility of the retraction process for scientific papers.

Orvig says it was important and the right thing to do to correct the literature, even if a little embarrassing, given that some researchers might have already tried to make the ligand and failed, and others might continue to do so. “This is the way science is supposed to work—correcting itself,” Orvig says.

Retracting a paper oftentimes is associated with misconduct—fabrication, plagiarism, or rigged peer review. Some researchers have suggested that papers like Orvig’s should be given a status different than retraction: For example, “withdrawal” could be used for an honest mistake, and “retraction” could be reserved for misconduct.

Inorganic Chemistry editor-in-chief William B. Tolman of the University of Minnesota applauds Orvig for coming forward to self-correct the mistake, when others might not have done so. “This is precisely why the retraction mechanism exists—to correct the published record,” Tolman says. “Orvig realized the error, did a bunch of work to reexamine it, and then pushed to have it corrected in the literature despite it being years later.” Tolman adds that he would hope researchers view this case as one of many data points in the larger story of how science corrects itself.


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