Samuel W. Thomas III, assistant professor of Chemistry, published Structure, Photophysics, and Photooxidation of Crowded Diethynyltetracenes in the Journal of Materials Chemistry with Tufts co-authors Jingjing Zhang, graduate student in chemistry, and Syena Sarrafpour, undergraduate student in biochemistry. The abstract is below -
This paper describes a previously unreported class of sterically crowded tetracene derivatives that have
both phenyl and ethynyl substituents. The steric crowding above and below the tetracene core prevents
overlap between the extended p-systems of the acenes. Substituent effects cause these tetra-substituted
tetracenes to have absorbance and fluorescence spectra red shifted from either disubstituted derivatives
or rubrenes, such that they have spectra similar to diarylpentacenes, but with higher quantum yields of
fluorescence and greater photostability. These new molecules also undergo cycloaddition reactions with
1O2, giving regioisomeric mixtures of endoperoxides, and in contrast to longer acenes, the ethynyl
substituents show only a modest stabilizing effect to photooxidation. Ethynylated tetracenes also
exhibited photochromism, with their endoperoxides undergoing cycloreversion to yield the acene
starting material at room temperature in the dark.
Samuel has answered some questions about open access.
Please tell us a little about the research that went into this article.
This research paper actually started with a very simple hypothesis about the chemical structures of what we thought would be an interesting new class of molecules, and their properties such as reactivity and color. Our major expectations turned out to be mostly correct, but along the way we learned some really interesting things about these new molecules that we didn’t expect. Most surprising was that their main chemical reaction that we were studying—the cycloaddition of these tetracene derivatives and singlet oxygen—was reversible. WIth heating to only 50 °C, we could reverse the key chemical reaction and wind up with our starting material again. We are looking into using that feature for new responsive materials. Also, the paper was a highly collaborative effort. Along with a graduate student and undergraduate from our lab, a chemistry faculty colleague and an outside collaborator are co-authors. Their contributions to the X-ray crystallography described in this paper helped take this work to the next level.
Why did you choose to publish in an open access journal?
I support the open access model of publishing, because it can increase the visibility of our work and enable more researchers to learn from our papers. We took advantage of the hybrid model used by the Royal Society of Chemistry, which is not an ‘open-access’ publisher per se, but does allow authors to pay for readers to have open access to their paper. The best chemistry journals only use this type of hybrid model for open access.
How do you think open access will influence your field in the future?
Nearly all major publishers in the chemical sciences offer a type of open access option for authors, but that is still somewhat restrictive. If a highly regarded open-access chemistry journal emerges it could change the way chemists look at publishing their highest-impact results.