Ultrafast polyene dynamics: the ring opening of 1,3-cyclohexadiene derivatives

Abstract

The light activated ring-opening reaction of the 1,3-cyclohexadiene chromophore finds application in optical control, optical switching, optical memory, light activated molecular machines, photobiology, photochromic materials, and conformation-specific photocatalysts. The development of ultrafast spectroscopic methods and powerful computational methods have accelerated the understanding and facilitated the application of this important chromophore in a wide range of systems. Here we look at the current state of theoretical and experimental understanding for the ring-opening reaction of the isolated cyclohexadiene molecule and the ring-opening reactions of substituted cyclohexadienes, including fulgides, diarylethenes, and provitamin D.

Femtosecond x-ray spectroscopy of an electrocyclic ring-opening reaction

“…Although time-resolved spectroscopic studies have allowed temporal tracing of the excitedstate dynamics (10,(12)(13)(14) and recent femtosecond x-ray scattering experiments have even revealed the time-evolving molecular structure directly (16), a direct characterization of the transient valence electronic structure in the intermediate excited-state region has remained elusive. Here, we report femtosecond soft x-ray absorption spectroscopy near the carbon K-edge with spectroscopic analysis from time-dependent density functional theory (TDDFT) calculations of the x-ray spectra to directly reveal the evolution of the valence electronic structure during the photochemical ring-opening reaction in real time.…”

GPU-Accelerated State-Averaged Complete Active Space Self-Consistent Field Interfaced with Ab Initio Multiple Spawning Unravels the Photodynamics of Provitamin D3

“…Aside from its obvious biological importance, Pro is a model system for understanding how to optically control polyene chromophores, which has potential applications in nanoscience. 52 This reaction has been studied both experimentally [53][54][55][56][57][58][59][60][61][62] and theoretically. [63][64] Critical points on Pro potential energy surfaces are represented in Figure 1 (SA-3-CAS(6,4)/6-31G, see SI for details and validation of the electronic structure employed).…”

Effects of probe energy and competing pathways on time-resolved photoelectron spectroscopy: the ring-opening of 1,3-cyclohexadiene

“…1. [9][10][11] Absorption of UV light at approximately 266 nm places the wavepacket on the steeply repulsive potential energy surface of the optically bright 1B 1 pp* state, with the wavepacket accelerated ballistically towards the diabatic 2A spectroscopically dark state on a o50 fs timescale. It returns to the 1A electronic ground state through a conical intersection, leading to either the ring-open 1,3,5-hexatriene (HT) photoproduct or the ring-closed CHD molecule.…”

“…12 Interest in this reaction is driven by its role as a model system for modern mechanistic photochemistry. [9][10][11] The CHD ringopening is a prototypical pericyclic reaction and has contributed to the development and corroboration of the Woodward-Hoffman rules, 13 which predict the stereochemical outcome for pericyclic reactions by correlating the first excited state of the reactant with the first excited state of the product and the ground state of the reactant with a doubly excited state of the product, and vice versa. This yields a pericyclic minimum in the first excited state, which acts as photochemical funnel that provides an efficient path for internal conversion.…”