1. CP-FTMW SPECTROSCOPY OF A CLAISEN REARRANGEMENT PRECURSOR ALLYL PHENYL ETHER
G. S. Grubbs IIa, Derek S. Frankb, Daniel A. Obenchainb, S. A. Cookec, and Stewart E. Novickb
71st International Symposium on Molecular Spectroscopy
June 20-24, 2016, Urbana-Champaign, IL, USA; MI02

2. Claisen Rearrangement
Allyl Phenyl Ether
2-Allylphenol
Discovered by L. Claisen1 in 1912
3,3 sigmatropic rearrangement
Structure and conformation are key to reaction

3. Allyl Phenyl Ether Theory
Calculations ran at MP2/6-311G++(3d,2p) level1
Gaussian 09, Revision A.02, M. J. Frisch et al, Gaussian, Inc., Wallingford CT, 2009.
2-Allylphenol

4. Allyl Phenyl Ether Theory
Parameter
APE Conf. 1
APE Conf. 2
APE Conf. 3
APE Conf. 4
2-Allylphenol
A / MHz
4539.7
4193.8
2825.8
3419.5
2511.4
B / MHz
631.8
693.3
868.4
739.9
1008.0
C / MHz
567.2
597.2
718.2
664.2
795.4
∆E / cm-1
63.3
633.0
714.4
---
𝜇 𝑎 /Debye
1.14
0.32
1.13
0.90
1.26
𝜇 𝑏 /Debye
0.52
0.88
0.91
𝜇 𝑐 /Debye
0.18
0.00
0.10
0.26
0.43
Calculations ran at MP2/6-311G++(3d,2p) level1
Gaussian 09, Revision A.02, M. J. Frisch et al, Gaussian, Inc., Wallingford CT, 2009.

5. Experiment Chirped-Pulse FTMW experiment1
G. S. Grubbs II, R. A. Powoski, D. Jojola and S. A. Cooke. J. Phys. Chem. A 114(2010)
Chirped-Pulse FTMW experiment1
99% APE in “U”-shaped tube bubbled with Ar at 2 atm
30,000 FIDs collected
Linewidths ~80 kHz with 10 kHz uncertainty

6. Results
Originally PFPA and Hydrates in spectra
8-14 GHz

7. Some Notes about Conf. Assignment
Conf. 1 consisted of a-type and b-type R-branch as well as b-type Q-branch transitions
Conf. 2 consisted of a-type and b-type R-branch as well as b-type Q-branch transitions
Conf. 1 transitions were, as a whole, stronger in intensity
Conf. 2 spectra were predominantly b-type while Conf. 1 spectra were predominantly a-type

8. APE Spectroscopic Parameters
Conformer 1
Conf. 1 Theory
Conformer 2
Conf. 2 Theory
A /MHz
(2)
4539.7
(5)
4193.8
B /MHz
(1)
631.8
(8)
693.3
C /MHz
(1)
567.2
(8)
597.2
𝛥J /kHz
0.0176(7)
---
0.03(1)
𝛥JK /kHz
-0.124(7)
-0.10(2)
𝛥K /kHz
4.5(5)
-3.(1)
δK /kHz
0.4(1)
ΦJ /mHz
54.(34)
RMS /kHz
4.5
7.6 N 61 41
SPFIT/SPCAT: H. M. Pickett, J. Mol. Spectrosc. 148 (1991) 371
AABS Package : Z. Kisiel, L. Pszczolkowski, I. R. Medvedev, M. Winnewisser, F. C. D. Lucia, C. E. Herbst, J. Mol. Spectrosc. 233 (2005) 231.

9. Calculated Structure

10. Second Moment Arguments
“Do you have a moment? No… Well, do you have a second moment? Ahh…” -Robert Bohn, almost every seminar
Second Moment
APE Conf.1
APE Conf. 2
Paa / uÅ2
(1)
(7)
Pbb / uÅ2
(1)
(7)
Pcc / uÅ2
9.4617(1)
1.9355(7)
Using Bob Bohn’s methods1 of determining out of plane contributions, Conf. 2 is confirmed to be essentially planar. This similar to the calculations because only the hydrogens are contributing to Pcc. Pbb is very similar to Phenetole’s value confirming
1. R. K. Bohn, J. A. Montgomery, Jr., H. H. Michels, J. A. Fournier. J. Mol. Spectrosc. (2016) In Press.

11. Structural Comparisons
Second Moment
Anisole1,2
Phenetole3
1-Phenyl-1-butyn-3-ene4
Paa / uÅ2
(9)
(2)
880.87(1)
Pbb / uÅ2
(9)
(2)
101.72(1)
Pcc / uÅ2
(9)
(2)
0.21(1)
Second Moment
APE Conf.1
APE Conf. 2
Paa / uÅ2
(1)
(7)
Pbb / uÅ2
(1)
(7)
Pcc / uÅ2
9.4617(1)
1.9355(7)
O. Desyatnyk, L. Pszczółkowski, S. Thorwirth, T. M. Krygowski, and Z. Kisiel. PCCP 7 (2005) 1708.
B. Reinhold, I. A. Finneran, S. T. Shipman, J. Mol. Spectrosc. 270 (2011) 89.
L. Ferres, W. Stahl, H. V. L. Nguyen. Mol. Phys. (2016) DOI: AND MI01 (Previous Talk)
J. A. Sebree, D. F. Plusquellic, T. S. Zwier, J. Mol. Spectrosc. 270 (2011) 98.

12. Chemical Implications
Ortho C-CH2 Carbon distance: Å
Ortho C-CH2 Carbon distance: Å
Structural reasons prevent rearrangement!!!
Ortho C-CH2 Carbon distance: Å
Ortho C-CH2 Carbon distance: Å

13. Conclusions
First reported phenyl-containing ether with multiple observed conformers
2nd Moment Confirmed Structures (Someone is listening, Bob Bohn)
No observation of 2-Allylphenyl Ether nor Conf. 3 or 4 indicate rearrangement is unlikely due to structural reasons
Never, EVER give up!!! (First Talk at ISMS 67)!
Paper: J. Mol. Spectrosc. 324 (2016) 1.

14. Acknowledgements
NSF CHE , Missouri S&T Startup and a UM Research Board Grant for $$$
Bob Bohn’s useful 2nd Moment Relationships