Seminar: Dynamics of Dienes: A Twist on Ring Formation


Wednesday 19/06/19, 11:00 am

Building 211, seminar room



Dr. Joshua Baraban

Senior Lecturer Dep. of Chemistry,

Ben-Gurion University



Dynamics of Dienes: A Twist on Ring Formation


          The three dimensional structures of molecules are often based on cyclic molecular motifs.  One of the most famous mechanisms for organic ring formation is the Diels-Alder reaction, where a dienophile and conjugated diene link together.  We recently detected the reactive conformer for the canonical Diels-Alder reaction, gauche 1,3-butadiene, by high resolution spectroscopy and determined its structure for the first time. [1-2] Notably, this was made possible only by a combination of cutting edge experimental and theoretical techniques. [3] Our studies reveal unusual quantum mechanical effects in the electronic and nuclear dynamics of these conjugated dienes, and have implications for many related ubiquitous compounds, such as isoprene. [4-5]

[1] J. H. Baraban, M.-A. Martin-Drumel, P. B. Changala, S. Eibenberger, M. Nava, D. Patterson, J. F. Stanton, G. B. Ellison, and M. C. McCarthy. The molecular structure of gauche-1,3-butadiene: Experimental establishment of non-planarity. Angewandte Chemie International Edition, 57:1821–1825, 2018.

[2] J. P. Porterfield, L. T. Nguyen, J. H. Baraban, G. T. Buckingham, T. Troy, O. Kostko, M. Ahmed, J. F. Stanton, J. W. Daily, and G. B. Ellison. Isomerization and Fragmentation of Cyclohexanone in a Heated Micro-Reactor. The Journal of Physical Chemistry A, 119:12635–12647, 2015.

[3] M.-A. Martin-Drumel, J. H. Baraban, P. B. Changala, J. F. Stanton, and M. C. McCarthy. The Hunt for Elusive Molecules: Insights from Joint Theoretical and Experimental Investigations. Chemistry - A European Journal, 25(30):7243–7258, 2019. (Invited Minireview, Reviews Showcase, Frontispiece).

 [4] J. P. Porterfield, J. H. Westerfield, L. Satterthwaite, D. Patterson, P. B. Changala, J. H. Baraban, and M. C. McCarthy. Rotational Characterization of the Elusive Gauche Isoprene. The Journal of Physical Chemistry Letters, 10(8):1981–1985, 2019.

[5] K. B. Wiberg, P. R. Rablen, and J. H. Baraban. Butadiene and Heterodienes Revisited. The Journal of Organic Chemistry, 83(15):8473–8482, 2018.