ADVERTISEMENT
2 /3 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Analytical Chemistry

Femtosecond X-ray Scattering

Chemical Physics: Intense ultrashort X-ray pulses trace ring-opening reaction step-by-step

by Mitch Jacoby
June 29, 2015 | APPEARED IN VOLUME 93, ISSUE 26

[+]Enlarge
Credit: SLAC National Accelerator Laboratory
Details of the reaction pathway taken by 1,3-cyclohexadiene during ring opening (lower left to upper right) have been elucidated by probing the process with femtosecond X-ray pulses.
09326-scicon-SLACLCLScxd.jpg
Credit: SLAC National Accelerator Laboratory
Details of the reaction pathway taken by 1,3-cyclohexadiene during ring opening (lower left to upper right) have been elucidated by probing the process with femtosecond X-ray pulses.

Researchers in California have used an X-ray scattering method to monitor step-by-step femtosecond structural rearrangements of a molecule undergoing a ring-opening reaction (Phys. Rev. Lett. 2015, DOI: 10.1103/physrevlett.114.255501). The study describes a new ultrafast pump-probe method that deepens understanding of chemical reaction dynamics and lays the groundwork for recording X-ray movies of chemical reactions in real time. To trigger the reaction, Michael P. Minitti of SLAC National Accelerator Laboratory and colleagues irradiated 1,3-cyclohexadiene vapor with ultraviolet laser light, which initiates ring opening and forms several conformers of 1,3,5-hexatriene. Then the team probed the evolution of the diene to the triene by scattering intense 30-femtosecond X-ray pulses from the unfolding molecules. By varying the delay between the UV and X-ray pulses, the team recorded a series of femtosecond X-ray diffraction snapshots, which they analyzed with quantum mechanical methods. The analysis shows that the reaction rapidly expands cyclohexadiene’s carbon bonds and that within one or two oscillations of the carbon skeleton, the C1–C6 bond breaks. The analysis also shows that the reaction’s stereochemical fate is sealed as early as 30 femtoseconds after the UV pulse.

X

Article:

This article has been sent to the following recipient:

Leave A Comment

*Required to comment