Trans- and cis-stilbene isolated in cryogenic argon and xenon matrices

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Unsalan O., Kus N., Jarmelo S., Faust R.

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, vol.136, pp.81-94, 2015 (SCI-Expanded) identifier identifier identifier


Monomers of trans- (TS) and cis-stilbene (CS) were isolated in cryogenic argon and xenon matrices, and
their infrared (IR) spectra were fully assigned and interpreted. The interpretation of the vibrational spectra
received support from theoretical calculations undertaken at the DFT(B3LYP)/6-311++G(d,p) level of
theory. In situ broadband UV irradiation of the matrix-isolated CS led to its isomerization to TS, which
appeared in the photolysed matrices in both non-planar and planar configurations. The non-planar species
was found to convert into the more stable planar form upon subsequent annealing of the matrices at
higher temperature. TS was found to be photostable under the used experimental conditions. The structure
of the non-planar TS form was assigned based on the comparison of its observed IR spectrum with
those theoretically predicted for different conformations of TS. Chemometrics was used to make this
assignment. Additional reasoning on the structure of the studied stilbenes is presented taking as basis
results of the Natural Bond Orbital analysis.