Our recent report on “molecular stress relief” and the real-time observation of a polymer growing longer as it is pulled has been highlighted on the Dec. 22 cover of JACS.
The lab’s work on “molecular stress relief” has been highlighted by the ACS as “Noteworthy Chemistry” in its Dec. 13 edition. Noteworthy Chemistry is a weekly feature produced by the American Chemical Society that collects and summarizes innovative ideas from the larger body of chemical literature. Originally designed as the “Heart Cut” department in the ACS publication CHEMTECH, Noteworthy Chemistry has become a valuable stand-alone resource for today’s informed chemistry professional.
Congratulations to Ashley Black & Jeremy Lenhardt, whose Feature Article, “From Molecular Mechanochemistry to Stress-Responsive Materials” has been published by J. Mater. Chem. A link to the mini-review is is provided here.
Dong and Jeremy’s paper on “molecular stress relief” has been published in J. Am. Chem. Soc. Using force spectroscopy, it is possible to observe a single polymer molecule literally growing longer in real time at strains that typically would lead to chain scission. The increased toughness at the single molecule level has possible consequences for the design and synthesis of new stress-responsive materials. The paper involves a collaboration with Prof. Boris Akhremitchev of the Florida Institute of Technology.
Our work on tension trapping and “contraction by extension” has been highlighted by Chemical and Engineering News.
Jeremy’s paper, “Trapping a Diradical Transition State by Mechanochemical Polymer Extension“, appears in the August 27 issue of Science. The paper describes how mechanical tension can be used to trap a gem-difluorocyclopropane (gDFC) in a 1,3-diradical that is formally a transition state in its stress-free electrocyclic isomerization. The trapped diradical lives long enough that we can observe its noncanonical participation in bimolecular addition reactions. Furthermore, the application of a transient tensile force induces a net isomerization of the trans–gDFC into its less-stable cis isomer, leading to the counterintuitive result that the gDFC contracts in response to a transient force of extension.
To hear Jeremy narrate an animated simulation of the force-induced chemistry (and let’s be honest — who wouldn’t want to hear that?), check out this Youtube video, or read more at the Futurity website.
Congratulations to Jeremy Lenhardt, who has kept the Departmental Recognition Award (and reserved parking space next to the building) in the group for another month. The Chair’s announcement of the award reads as follows:
The Departmental recognition award committee has decided that August’s Departmental recognition award (and the reserved parking space for that month) goes to Jeremy Lenhardt, first author on the newest Science paper out of Duke Chemistry.
As most of you know, general journals such as Science and Nature are exceedingly selective, and publication in such journals reflects well on the Department. The research needs to be more than just novel and important-it also has to be compelling to a general audience (when I consider such a submission, my first question is “Why would a geologist want to read this paper?”). Their paper (which will be out shortly) is entitled “Trapping a Diradical Transition State by Mechanochemical Polymer Extension.” It recognizes success in the chemical equivalent of catching lightning in a bottle — trapping (both dynamically and chemically) the transition state of a chemical reaction. Jeremy’s accomplishment is noteworthy in many respects, and it came with a fun and counterintuitive side story: a molecule that gets shorter after you pull it. Jeremy has had successes before (he is only the second Ph.D. student in our department’s history to have won an ACS Division of Organic Chemistry Graduate Student Fellowship), and other strong work is on the way.