Solvent-dependent complex reaction pathways of bromoform revealed by time-resolved X-ray solution scattering and X-ray transient absorption spectroscopy

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Abstract

The photochemical reaction pathways of CHBr3 in solution were unveiled using two complementary X-ray techniques, time-resolved X-ray solution scattering (TRXSS) and X-ray transient absorption spectroscopy, in a wide temporal range from 100 ps to tens of microseconds. By performing comparative measurements in protic (methanol) and aprotic (methylcyclohexane) solvents, we found that the reaction pathways depend significantly on the solvent properties. In methanol, the major photoproducts are CH3OCHBr2 and HBr generated by rapid solvolysis of iso-CHBr2-Br, an isomer of CHBr3. In contrast, in methylcyclohexane, iso-CHBr2-Br returns to CHBr3 without solvolysis. In both solvents, the formation of CHBr2 and Br is a competing reaction channel. From the structural analysis of TRXSS data, we determined the structures of key intermediate species, CH3OCHBr2 and iso-CHBr2-Br in methanol and methylcyclohexane, respectively, which are consistent with the structures from density functional theory calculations.

Detaljer

Författare
  • Qingyu Kong
  • Dmitry Khakhulin
  • Ilya A. Shkrob
  • Jae Hyuk Lee
  • Xiaoyi Zhang
  • Jeongho Kim
  • Kyung Hwan Kim
  • Junbeom Jo
  • Jungmin Kim
  • Jaedong Kang
  • Van Thai Pham
  • Guy Jennings
  • Charles Kurtz
  • Rick Spence
  • Lin X. Chen
  • Michael Wulff
  • Hyotcherl Ihee
Externa organisationer
  • Synchrotron SOLEIL
  • Liaocheng University
  • European XFEL GmbH
  • Argonne National Laboratory
  • Pohang University of Science and Technology
  • Inha University
  • Korea Advanced Institute of Science and Technology
  • Institute for Basic Science, Korea
  • Northwestern University
  • European Synchrotron Radiation Facility
Originalspråkengelska
Artikelnummer064902
TidskriftStructural Dynamics
Volym6
Utgåva nummer6
StatusPublished - 2019 nov 1
PublikationskategoriForskning
Peer review utfördJa
Externt publiceradJa