Fig. 5: Chemical quantum calculations of the photoisomerization of thioindigo.
a Optimized geometries and the corresponding frontier molecular orbitals of the trans- (the left panel) and cis- forms (the right panel) of photoswitch thioindigo in the ground state. The insets show the energy levels of frontier molecular orbitals and the corresponding electronic gaps (level of theory: M06-2X/def2-TZVP in dichloromethane; b Calculated relative Gibbs free energy (ΔG), peak UV-vis absorption wavelengths (λabs), and ground state dipole moment (µ) of the trans- and cis-forms of thioindigo; c Potential energy surface (PES) in the ground state (S0), as a function of θ. d Potential energy surface (PES) in the excited state (S1) and the ground state (S0), as a function of θ, based on optimized geometries in the S1 state (the top panel), and the optimized geometries and the corresponding frontier molecular orbitals of the trans- and cis-forms of thioindigo (the bottom panel). The inset highlights the dihedral angle θ, representative molecular structures on the PES, as well as the energy barriers. e Optimized geometries of thioindigo-methanol complex in the first excited state (S1). The insets show the hydrogen bond distances and associated energy. Level of theory: M06-2X/def2SVP in dichloromethane for (c) to (e).
