A QM/MM study of the conformation stability and electronic structure of the photochromic switches derivatives of DHA/VHF in acetonitrile solution
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A QM/MM study of the conformation stability and electronic structure of the photochromic switches derivatives of DHA/VHF in acetonitrile solution. / Cardenuto, Marcelo Hidalgo; Cezar, Henrique M.; Mikkelsen, Kurt Valentin; Sauer, Stephan P. A.; Coutinho, Kaline; Canuto, Sylvio.
I: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Bind 251, 119434, 2021.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - A QM/MM study of the conformation stability and electronic structure of the photochromic switches derivatives of DHA/VHF in acetonitrile solution
AU - Cardenuto, Marcelo Hidalgo
AU - Cezar, Henrique M.
AU - Mikkelsen, Kurt Valentin
AU - Sauer, Stephan P. A.
AU - Coutinho, Kaline
AU - Canuto, Sylvio
PY - 2021
Y1 - 2021
N2 - We present a detailed theoretical study of the electronic absorption spectra and thermochemistry of molecular photoswitches composed of one and two photochromic units of dihydroazulene (DHA)/vinylheptafulvene (VHF) molecules. Six different isomers are considered depending on the ring opening/closure forms of the DHA units. The solvent effect of acetonitrile is investigated using a sequential Molecular Mechanics/Quantum Mechanics approach. The thermochemical investigations of these photochromic molecules were performed using the Free Energy Perturbation method, and the simulations were performed using Configurational Bias Monte Carlo. We show that to open the 5-member ring of the DHA, there is no significant gain in thermal release of energy for the back reaction when a unit or two DHA units are considered. Overall, we found agreement between the solvation free energy based on Monte Carlo simulations and the continuum solvent model. However, the cavitation term in the continuum model is shown to be a source of disagreement when the non-electrostatic terms are compared. The electronic absorption spectra are calculated using TDDFT CAM-B3LYP/cc-pVDZ. Agreement with experiment is obtained within 0.1 eV, considering statistically uncorrelated configurations from the simulations. Inhomogeneous broadening is also considered and found to be well described in all cases.
AB - We present a detailed theoretical study of the electronic absorption spectra and thermochemistry of molecular photoswitches composed of one and two photochromic units of dihydroazulene (DHA)/vinylheptafulvene (VHF) molecules. Six different isomers are considered depending on the ring opening/closure forms of the DHA units. The solvent effect of acetonitrile is investigated using a sequential Molecular Mechanics/Quantum Mechanics approach. The thermochemical investigations of these photochromic molecules were performed using the Free Energy Perturbation method, and the simulations were performed using Configurational Bias Monte Carlo. We show that to open the 5-member ring of the DHA, there is no significant gain in thermal release of energy for the back reaction when a unit or two DHA units are considered. Overall, we found agreement between the solvation free energy based on Monte Carlo simulations and the continuum solvent model. However, the cavitation term in the continuum model is shown to be a source of disagreement when the non-electrostatic terms are compared. The electronic absorption spectra are calculated using TDDFT CAM-B3LYP/cc-pVDZ. Agreement with experiment is obtained within 0.1 eV, considering statistically uncorrelated configurations from the simulations. Inhomogeneous broadening is also considered and found to be well described in all cases.
KW - Faculty of Science
KW - QM/MM method
KW - absorption spectroscopy
KW - Electronic structure
KW - photoswitches
KW - Solvent effects
U2 - 10.1016/j.saa.2021.119434
DO - 10.1016/j.saa.2021.119434
M3 - Journal article
C2 - 33465576
VL - 251
JO - Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
JF - Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
SN - 1386-1425
M1 - 119434
ER -
ID: 255002150