1. ANALYSIS OF ROTATIONAL STRUCTURE IN THREE C-TYPE BANDS IN THE HIGH-RESOLUTION INFRARED SPECTRUM OF trans,trans-1,3,5-HEXATRIENE
NORMAN C. CRAIG, MATTHEW C. LEYDEN, and AMIE K. PATCHEN,Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH 44074, USA
TONY MASIELLO, Environmental and Molecular Sciences Laboratory, Pacific Northwet National Laboratory, P. O. Box 999, Mail Stop k8-88, Richland, WA 99352

2. 1,3-Butadiene
Blue: re structure. N. C. Craig, P. Groner, D. C. McKean, J. Phys.
Chem. A, 2006, 110,
Red: localized C=C and sp2-sp2 bond lengths.

3. cis- and trans-1,3,5-Hexatriene B3LYP/cc-pVTZ Model

4. Synthesis

5. IR Spectrum of trans-Hexatriene at 0.1 cm-1 resolution.

7. Absorbance Spectrum of trans-Hexatriene

8. C1 Band in Absorbance

9. C1 Band - Detail of Subband Assignments in R the Branch

10. Center of C1 Band
Calculated
Observed

11. C2 Band in Absorbance

12. C3 Band in Absorbance

13. Loomis-Wood Display for Part of the C3 Band

14. Loomis-Wood Display of RR7, RR8, and RR9 Subbands in the C3 Band

15. Rotational Constants

16. Conclusions
Rotational analysis of nonpolar trans-hexatriene depends on high-resolution ( cm-1) infrared spectroscopy.
Rotational structure in 3 C-type bands has been analyzed.
Hot bands from the torsional mode at 94 cm-1 and the in-plane
bend at 152 cm-1 cause congested spectra.
GS rotational constants from GSCDs of 14(au) at 1011 cm-1, 16(au) at 901 cm-1, and 17(au) at 683 cm-1 taken together are reported.
US rotational constants are reported for 16(au) at 901 cm-1.
First step toward an equilibrium structure for trans-hexatriene.
Various carbon-13 and deuterium isotopomers must be made, and their rotational constants found.

17. Support Oberlin College Dreyfus Foundation.
Pacific Northwest National Laboratory Operated by Battelle as a DOE Contractor.
Oberlin College