title: Theoretical Investigation of Substituent Effects on the Dihydroazulene/Vinylheptafulvene Photoswitch: Increasing the Energy Storage Capacity.
abstract: We have investigated the effects of substituents on the properties of the dihydroazulene/vinylheptafulvene photoswitch. The focus is on the changes of the thermochemical properties by placing electron withdrawing and donating groups on the monocyano and dicyano structures of the parent dihydroazulene and vinylheptafulvene compounds. We wish to increase the energy storage capacity, that is, the energy difference between the dihydroazulene and vinylheptafulvene isomers, of the photoswitch by computational molecular design and have performed over 9000 electronic structure calculations using density functional theory. Based on these calculations, we obtain design rules for how to increase the energy storage capacity of the photoswitch. Furthermore, we have investigated how the activation energy for the thermally induced vinylheptafulvene to dihydroazulene conversion depends on the substitution pattern, and based on these results, we have outlined molecular design considerations for obtaining new desired target structures exhibiting long energy storage times. Selected candidate systems have also been investigated in terms of optical properties to elucidate how sensitive the absorption maxima are to the functionalizations.
authors.affiliation: Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
authors.forename: Mia Harring
authors.initials: MH
authors.lastname: Hansen
authors.affiliation: Department of Physics, Helsinki University , P.O. Box 64, 00100 Helsinki, Finland.
authors.forename: Jonas
authors.initials: J
authors.lastname: Elm
authors.affiliation: Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
authors.forename: Stine T
authors.initials: ST
authors.lastname: Olsen
authors.affiliation: Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
authors.forename: Aske Nørskov
authors.initials: AN
authors.lastname: Gejl
authors.affiliation: Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
authors.forename: Freja E
authors.initials: FE
authors.lastname: Storm
authors.affiliation: Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
authors.forename: Benjamin N
authors.initials: BN
authors.lastname: Frandsen
authors.affiliation: Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
authors.forename: Anders B
authors.initials: AB
authors.lastname: Skov
authors.affiliation: Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
authors.forename: Mogens Brøndsted
authors.identifier: http://orcid.org/0000-0001-8377-0788
authors.initials: MB
authors.lastname: Nielsen
authors.affiliation: Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
authors.forename: Henrik G
authors.initials: HG
authors.lastname: Kjaergaard
authors.affiliation: Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
authors.forename: Kurt V
authors.initials: KV
authors.lastname: Mikkelsen