Identifying the major intermediate species by combining time-resolved X-ray solution scattering and X-ray absorption spectroscopy

Kyung Hwan Kim, Jeongho Kim, Key Young Oang, Jae Hyuk Lee, Daniel Grolimund, Christopher J. Milne, Thomas J. Penfold, Steven L. Johnson, Andreas Galler, Tae Wu Kim, Jong Goo Kim, Deokbeom Suh, Jiwon Moon, Joonghan Kim, Kiryong Hong, Laurent Guérin, Tae Kyu Kim, Michael Wulff, Christian Bressler, Hyotcherl Ihee

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Identifying the intermediate species along a reaction pathway is a first step towards a complete understanding of the reaction mechanism, but often this task is not trivial. There has been a strong on-going debate: which of the three intermediates, the CHI2 radical, the CHI2-I isomer, and the CHI2+ ion, is the dominant intermediate species formed in the photolysis of iodoform (CHI3)? Herein, by combining time-resolved X-ray liquidography (TRXL) and time-resolved X-ray absorption spectroscopy (TR-XAS), we present strong evidence that the CHI2 radical is dominantly formed from the photolysis of CHI3 in methanol at 267 nm within the available time resolution of the techniques (∼20 ps for TRXL and ∼100 ps for TR-XAS). The TRXL measurement, conducted using the time-slicing scheme, detected no CHI2-I isomer within our signal-to-noise ratio, indicating that, if formed, the CHI2-I isomer must be a minor intermediate. The TR-XAS transient spectra measured at the iodine L1 and L3 edges support the same conclusion. The present work demonstrates that the application of these two complementary time-resolved X-ray methods to the same system can provide a detailed understanding of the reaction mechanism.

Original languageEnglish
Pages (from-to)23298-23302
Number of pages5
JournalPhysical Chemistry Chemical Physics
Volume17
Issue number36
DOIs
Publication statusPublished - 2015 Aug 14

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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