Archive for the ‘Polymers’ Category

Suspicious Data in a JACS Paper from 2009

Thursday, November 7th, 2013

Covers of JACSOn Tuesday, the Journal of the American Chemical Society published a retraction notice for a paper titled “Bimetallic Effects for Enhanced Polar Comonomer Enchainment Selectivity in Catalytic Ethylene Polymerization” by Brandon A. Rodriguez, Massimiliano Delferro, and Tobin J. Marks (J. Am. Chem. Soc. 2009, 131, 5902−5919).

The retraction notice reads:

The authors have been unable to reproduce the synthesis and spectroscopic characterization of the ethylene/acrylate copolymer described in this article. Accordingly, the authors are retracting this publication due to concerns over the validity of the aforementioned data. The authors regret any confusion that may have been created by publication of this work.

A casual reader might encounter this notice and think this is exactly how the system should work: a scientist told of a problem with his published procedure went back, attempted to repeat the work, found he couldn’t, and published a notice to inform the community.

But a closer inspection reveals that there is more to this story that the retraction notice would indicate.

ChemBark was alerted to problems with this paper in August by an astute chemist who wishes to remain anonymous. One day earlier, the source had contacted Peter Stang, the editor-in-chief of JACS, to alert the journal to abnormalities with data in the paper. ChemBark respected the wishes of the source and allowed a traditional editorial review of the paper to be completed before reporting the matter on the blog. With the publication of the retraction notice yesterday, the authors have publicized that their work is problematic. It would appear that an initial review of the paper is complete.

The authors’ wording of the retraction does not indicate specifically what was wrong with the paper, but a brief inspection of the data (including those in the Supporting Information) reveals the following abnormalities:

Figure 3: The baselines of these spectra are peculiar in that they are thick but very straight. The thicknesses and shapes of the peaks are also peculiar. Some of the tall peaks lack the wide bases you would expect of them. Finally, some of the peaks appear to have a different background (i.e., noise) and line thickness (as if they originated from a different source).


Figure 6: The baselines (i.e., noise) of the two NMR spectra appear to be identical. The peaks look irregular—like solid lines.

Figure 7: Again, some of the peaks have lines that are much thicker than the rest of the spectrum. They look unnatural.

Figure S19 (in the SI): The NMR spectra taken at various temperatures have identical noise in their baselines, which would be very, very unusual. The peaks of interest appear irregular and have different line shapes.


Figure S21: The background of the peaks appears different from the background of the rest of the spectrum, as if the peaks were cut-and-pasted into the spectrum.

Figure S22: Same as above. The spectrum in Figure S21 and the bottom spectrum of Figure S22 appear to have the same baseline noise even though these spectra are reported to be of two entirely different compounds.


That’s not everything that looks peculiar, but do not simply take my word for it. Go to the paper, have a look, and judge for yourself (paper, SI). ChemBark does not know why these data look the way they do, but they do look unnatural.

On Tuesday, ChemBark contacted Professors Tobin Marks (the corresponding author on the retracted paper) and Peter Stang (the Editor-in-Chief of JACS) by e-mail for comment.

A response was received on Wednesday from Alan K. Cubbage, the chief communications officer for Northwestern University. In the interest of fairness, we are reporting this e-mail its entirety:

Mr. Bracher, your inquiry to a Northwestern University professor, Tobin Marks, was referred to me, as I am the chief communications officer for Northwestern.

As you note in your email, two Northwestern University faculty members and a former Ph.D. student have retracted a publication that appeared several years ago in the Journal of the American Chemical Society. The authors are Brandon A. Rodriguez, who received a Ph.D. from Northwestern in 2009, Tobin Marks, a professor of chemistry, and Massimiliano Delferro, a research assistant professor of chemistry. The article was retracted because the authors were unable to reproduce a portion of the data described in the article.

Northwestern University has established processes and procedures for reviewing issues relating to research integrity.  If concerns were to be raised regarding the data that was the subject of the retraction, the University would use those procedures in its review.  Part of those procedures, which follow the steps mandated by the federal government, is that any review remains confidential.

Thank you for your interest in Northwestern.

Best wishes,

Alan Cubbage

ChemBark also received an e-mail response from Peter J. Stang, the Editor-in-Chief of JACS. In addition to asking about the possibility of fabrication and the specific concerns listed above, we asked for his thoughts on Paul Weiss’s recent editorial in ACS Nano. Dr. Stang’s message is also copied below in its entirety, with the exception of one paragraph (that will be communicated in the next post on the blog, a follow-up to this story):

Dear Dr. Bracher:

Thank you for your communication regarding  Bimetallic Effects for Enhanced Polar Comonomer Enchainment Selectivity in Catalytic Ethylene Polymerization   authored by Brandon A. Rodriguez, Massimiliano Delferro, and Tobin J. Marks [] that has been retracted {10.1021/ja409590r] from the Journal of the American Chemical Society (JACS).

As you know, concerns with this paper were brought to my attention in late August by an anonymous source.  Apparently this source also communicated the same concerns to you.  I am disappointed that you felt obligated to  not communicate these concerns  to JACS directly  at that time and deferred to your source to do so. Please know that JACS takes all allegations regarding the validity of  data reported in published articles very seriously.

These concerns were shared with the author and a  thorough editorial review of the article and accompanying information was conducted by JACS. The authors have retracted the article – it would not be proper to speculate on some of the questions you have posed.

(Omitted paragraph — to be discussed in next post)

ACS and its Editors adhere to the principle that the observance and practice of high ethical standards is vital to the entire scientific enterprise.  Toward that end, guidelines for a course of conduct by those engaged in the publication of chemical research, specifically, editors, authors, and manuscript reviewers are set forth in ACS Ethical Guidelines to Publication of Chemical Research -

ACS Publications  is a member of the Committee on Publication Ethics (COPE). ACS Editors adhere to  a process established by COPE to review suspicious/fabricated data -

With regard to the editorial in ACS Nano, I believe that it is well-reasoned and articulated. Public speculation and  finger-pointing before all of the facts are gathered, assessed and decided upon is, in my opinion, counterproductive.  A confidential rigorous review of allegations based on the COPE  prescribed process is the best means to determine an appropriate action in response to those allegations.  As you know, outcomes of these reviews may very well have a lasting impact on the researcher(s) involved and we need to let the facts dictate those outcomes.

Thank you for advising that ChemBark will post a story on the retraction I offer my assistance in reviewing a draft and through cc have alerted  Dr. Tobin, the corresponding author.

Peter J. Stang


ChemBark could not locate an e-mail address for Dr. Brandon Rodriguez, the first author on the paper, but did send him a message seeking comment through Facebook. We received no reply. We will publish any comments from Dr. Rodriguez as soon as possible after they are received, and we note that he (and everyone) is welcome to post comments in the discussion thread below. We also note that the community owes a debt of gratitude to the chemist who brought these concerns to light in a professional and considerate manner.

So…here we have a case where a suspicious paper from a very high-profile group was allowed to go through the “traditional” private review process espoused by scientists like the editor-in-chief of ACS Nano rather than public review on a blog. ChemBark did nothing to interfere with the investigation or the actions of the editors at JACS.

Is this how the system should work?


Editor’s Notes: Neither Dr. Stang nor anyone at Northwestern were allowed to view an early draft of this story. The spectra used to construct the images above were taken from figures in J. Am. Chem. Soc. 2009, 131, 5902−5919 (paper, SI). The next post on ChemBark will deal with how the journal handled a specific aspect of this review.