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Title: Femtosecond photodecarbonylation of photo-ODIBO studied by stimulated Raman spectroscopy and density functional theory
Photo-oxa-dibenzocyclooctyne (Photo-ODIBO) undergoes photodecarbonylation under UV excitation to its bright S 2 state, forming a highly reactive cyclooctyne, ODIBO. Following 321 nm excitation with sub-50 fs actinic pulses, the excited state evolution and cyclopropenone bond cleavage with CO release were characterized using femtosecond stimulated Raman spectroscopy and time-dependent density functional theory Raman calculations. Analysis of the photo-ODIBO S 2 CO Raman band revealed multi-exponential intensity, peak splitting and frequency-shift dynamics. This suggests a stepwise cleavage of the two C–C bonds in the cyclopropenone structure that is completed within <300 fs after excitation. Evidence of intramolecular vibrational relaxation on the S 2 state, concurrent with photodecarbonylation, with dynamics matching previous electronic transient absorption spectroscopy, was also observed. This confirms an excited state, as opposed to ground state, photodecarbonylation mechanism resulting in a vibronically excited photoproduct, ODIBO.  more » « less
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Author(s) / Creator(s):
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Date Published:
Journal Name:
Physical Chemistry Chemical Physics
Page Range / eLocation ID:
25637 to 25648
Medium: X
Sponsoring Org:
National Science Foundation
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