1. Beyond the Bend: Exploring the Conformational Landscape of Decyl, Undecyl, and Dodecylbenzene
Daniel M. Hewett, Simply John T. Lawler, and Timothy S. Zwier
Department of Chemistry, Purdue University
Funding: DOE Basic Energy Sciences
Combustion Program
Funding

2. Motivations ? ?
Nils O. B. Lüttschwager, Tobias N. Wassermann, Ricardo A. Mata, Martin A. Suhm
The Last Globally Stable Extended Alkane
Angew. Chem. Int. Ed. 52 (2013)
I would remove the reference to soot formation. It’s too subtle a connection to make.
Identifying the First Folded Alkylbenzene via Ultraviolet, Infrared, and Raman Spectroscopy of Pentylbenzene through Decylbenzene
Daniel M. Hewett, Sebastian Bocklitz, Daniel P. Tabor,
Edwin L. Sibert III,* Martin A. Suhm, and Timothy S. Zwier

3. Fluorescence Excitation and Dispersed Fluorescence Chamber
7/20/2018
Fluorescence Excitation and Dispersed Fluorescence Chamber
Detect total
fluorescence
UV laser tuned
Conformer A
(S0, ZPL)
A*(S1)

4. Ground State Methods LIF S0-FDIRS Tune UV Laser
Collect Total Fluorescence
Collect Total Fluorescence
Fix UV Laser
Add in a couple of words: on LIF: ‘Tune UV laser’ and ‘Collect total fluorescence’
On S0 FDIRS: Tune IR and ‘Fix UV on conformer origin’
Tune IR Laser
LIF
S0-FDIRS

5. Octylbenzene: g1g3g4 g=gauche defect in the chain
Eureka! Look at all that structure! no more lumps, theory predicts three major bands in middle region, gets the 2950 band from the double gauche, additional activity in low region
g=gauche defect in the chain

6. Folded vs. Extended Octylbenzene Folded All Trans
Eureka! Look at all that structure! no more lumps, theory predicts three major bands in middle region, gets the 2950 band from the double gauche, additional activity in low region
Octylbenzene Folded
All Trans

7. UV Spectra: S0-S1 origin region

8. Energy Level Diagrams
all trans
all trans
Octylbenzene
Decylbenzene

9. UV Spectra: S0-S1 origin region
Add relative scale from the all trans

10. Decylbenzene IR Spectra* * * *

11. Decylbenzene IR Spectra
g1g2g4g5 = 0.10 kJ/mol
g1g’4g’5 = 1.31 kJ/mol

12. Decylbenzene IR Spectra
g1g2g4g5 = 0.10 kJ/mol
g1g’4g’5 = 1.31 kJ/mol

13. Undecylbenzene IR Spectra* * * *

14. Dodecylbenzene IR Spectra* * *

15. Future Work
Diaryls
Where’s the stack?

16. Conclusions
Observed rapid increase in folded conformer population as chain length increases
Alkyl CH stretch region becoming very difficult to use as a spectroscopic tool as chain length increases

17. Acknowledgements Dr. Tim Zwier Simply John T. Lawler The Zwier group
DOE