Conformational control in the photochemistry of hexatriene derivatives

ORAL

Abstract

The photochemistry of hexatriene (HT) is determined by the ground state equilibrium of different rotamers. Different side chains and their relative positions on the HT backbone structure have different effects on the equilibrium between the different rotamers. To investigate the influence of the side chains on the relative statistical weight of the rotamers at equilibrium, we studied HT and two of its derivatives: (3Z)-2-isopropyl-5-methylhexa-1,3,5-triene (IPMHT) and (3Z,5E)-3,7-dimethylocta-1,3,5-triene (DOT). To effectively sample the ground state equilibrium of these molecules we use ab initio replica exchange molecular dynamics (REMD) based on density functional theory (DFT). We perform the simulation with and without empirical correction for dispersion forces. Based on the equilibrium of structures in the ground state we calculate electronic absorption spectra using time-dependent DFT (TDDFT). Results from the study show that there is an influence of the conformation of the molecules on the excitation energy. This principle can be used to selectively excite a group of rotamers. Our calculated data will be compared to experimental data in order to determine the accuracy of the empirical correction for dispersion forces and if rotamers can be selectively excited experimentally.

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Authors

  • Alysson Vrielink

    Caifornia State University, Long Beach, University of California, Merced, Stanford University

  • Chi-Yu Hu

    University of California - Berkeley, National Institute for Materials Science, Caifornia State University, Long Beach, University of Michigan, Stockholm University, California State University, Long Beach, Utrecht University, Carl von Ossietzky University of Oldenburg, Germany, Hartnell Community College, Department of Physics, Stockholm University, GRAPPA, University of Amsterdam, Paul Scherrer Institute, Switzerland, California State University, Fresno, California State University Long Beach, Cal State Univ- Long Beach, University of Nevada, Reno, University of Rogensberg, Germany, Tribhuvan University, Nepal, University of Victoria and Perimeter Institute for Theoretical Physics, Institute of Physics, Jagiellonian University, Helmholtz Institute Mainz, Johannes Gutenberg University, Physics Department of the University of Nevada, Reno, Universita del Sannio, Cal Tech, California State University, Los Angeles, Univ of California - San Diego, UC Berkeley, Lawrence Livermore National Laboratory, Department of Physics & Astronomy, University of California, Irvine 92617, Department of Chemistry and of Physics & Astronomy, University of California, Irvine 92617, SLAC National Laboratory, Humboldt State University, Physics Department, University of Nevada, Reno, Univ of California - Merced

  • Chi-Yu Hu

    University of California - Berkeley, National Institute for Materials Science, Caifornia State University, Long Beach, University of Michigan, Stockholm University, California State University, Long Beach, Utrecht University, Carl von Ossietzky University of Oldenburg, Germany, Hartnell Community College, Department of Physics, Stockholm University, GRAPPA, University of Amsterdam, Paul Scherrer Institute, Switzerland, California State University, Fresno, California State University Long Beach, Cal State Univ- Long Beach, University of Nevada, Reno, University of Rogensberg, Germany, Tribhuvan University, Nepal, University of Victoria and Perimeter Institute for Theoretical Physics, Institute of Physics, Jagiellonian University, Helmholtz Institute Mainz, Johannes Gutenberg University, Physics Department of the University of Nevada, Reno, Universita del Sannio, Cal Tech, California State University, Los Angeles, Univ of California - San Diego, UC Berkeley, Lawrence Livermore National Laboratory, Department of Physics & Astronomy, University of California, Irvine 92617, Department of Chemistry and of Physics & Astronomy, University of California, Irvine 92617, SLAC National Laboratory, Humboldt State University, Physics Department, University of Nevada, Reno, Univ of California - Merced