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Research Integrity

Electro-Optics Paper Retracted

Materials science paper fails to cite inventor of chromophores used in research

by Elizabeth K. Wilson
March 10, 2014 | A version of this story appeared in Volume 92, Issue 10

A 2004 paper in the Elsevier journal Inorganica Chimica Acta has been retracted for failing to acknowledge the contributions of another scientist’s work included in the article (Inorg. Chim. Acta 2014, DOI: 10.1016/j.ica.2014.01.004).

The paper, “Advances in Organic Electro-Optic Materials and Processing,” was authored by University of Washington chemistry professor Larry R. Dalton and several members of his group. Dalton at the time headed the University of Washington’s multi-million-dollar Center on Materials & Devices for Information Technology Research (CMDITR). The paper described a new method for measuring molecular hyperpolarizability, an electronic property that is crucial in the development of materials that convert electrical signals into optical ones. Industry is eyeing such materials for ultrafast computers and communications devices.

To demonstrate the method, Dalton’s team used a class of electron donor-acceptor dyes called tricyanopyrroline (TCP) chromophores. But in their paper they failed to disclose that those chromophores were invented in the early 2000s by Bart Kahr, at the time a chemistry professor at the University of Washington, and his former postdoc Sei-Hum Jang.

After synthesizing the chromophores, Jang began preparing a paper, and he and Kahr filed for a patent.

Meanwhile, Jang had also begun working with chemistry professor Alex K-Y. Jen, who was part of Dalton’s center. Jang prepared the chromophores for the hyperpolarizability experiments in Kahr’s lab. Both Jang and Kahr were then surprised to discover that that work had been published by Dalton and his colleagues (Inorg. Chim. Acta 2004, DOI: 10.1016/j.ica.2004.07.031). Neither Jang nor Kahr had been told about the publication, and although Jang was listed as an author, Kahr was not. Jen was thanked in the acknowledgments section of the paper for his assistance.

The ICA retraction directs scientists to a subsequent paper, “Pyrroline Chromophores for Electro-Optics,” “for a complete account of research related to the TCP chromophores.” That paper was published in the American Chemical Society journal Chemistry of Materials in 2006, and it did include Kahr as an author and inventor of the TCP chromophores (Chem. Mat. 2006, DOI: 10.1021/cm052861i).

Elsevier did not respond to C&EN’s request for comment.

Dalton tells C&EN that the omission was the result of a number of communication failures. One failure was that he had given responsibility for the paper to two graduate students, one of whom didn’t realize the history of the chromophore’s development.

Jang brought the omission to CMDITR’s attention back in 2005, but he was rebuffed. Kahr continued working with the group but became increasingly concerned about other, more fundamental issues with the center, some of which were detailed in a 2012 news story in Nature (DOI: 10.1038/489017a).

Most important, Kahr says, the center failed to report to the National Science Foundation in grant applications that a key property of the center’s star materials was under question. Indeed, experiments by Kahr showed that the materials’ ability to line up in an electrical field, to which their remarkable electric-to-optic signal conversion abilities were attributed, was very weak.

Kahr moved to New York University in 2008. He then asked for an investigation into these issues, including the now-retracted ICA paper, by the University of Washington’s Office of Scholarly Integrity. The office found no evidence of wrongdoing and decided that the question of the 2004 paper’s authorship was the purview of ICA.

However, a Feb. 25 post on the blog Retraction Watch noted that in 1967, Dalton retracted a paper from the very same journal, ICA, after quoting results from a Russian team without ­acknowledgment.

Regarding the 2004 paper, according to Kahr and Dalton, it took much wrangling with the journal before the three parties reached a decision.

“The paper violated the journal authorship guidelines and was retracted, as it should be,” Kahr says.

“The last thing I wanted to do was claim credit for the material,” Dalton says. “The only resolution we could work out was to retract the article and refer to the 2006 publication, because no one will dispute that.”



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