title: Solar Thermal Energy Storage in a Photochromic Macrocycle.
abstract: The conversion and efficient storage of solar energy is recognized to hold significant potential with regard to future energy solutions. Molecular solar thermal batteries based on photochromic systems exemplify one possible technology able to harness and apply this potential. Herein is described the synthesis of a macrocycle based on a dimer of the dihydroazulene/vinylheptafulvene (DHA/VHF) photo/thermal couple. By taking advantage of conformational strain, this DHA-DHA macrocycle presents an improved ability to absorb and store incident light energy in chemical bonds (VHF-VHF). A stepwise energy release over two sequential ring-closing reactions (VHF→DHA) combines the advantages of an initially fast discharge, hypothetically addressing immediate energy consumption needs, followed by a slow process for consistent, long-term use. This exemplifies another step forward in the molecular engineering and design of functional organic materials towards solar thermal energy storage and release.
authors.affiliation: Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark.
authors.forename: Alexandru
authors.initials: A
authors.lastname: Vlasceanu
authors.affiliation: Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark.
authors.forename: Søren L
authors.initials: SL
authors.lastname: Broman
authors.affiliation: Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark.
authors.forename: Anne S
authors.identifier: http://orcid.org/0000-0002-6285-586X
authors.initials: AS
authors.lastname: Hansen
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.|Department of Chemistry, University of Florence, Via della Lastruccia 3-13, 50019, Sesto Fiorentino (FI), Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Cacciarini
authors.affiliation: Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Kadziola
authors.affiliation: Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark.
authors.forename: Henrik G
authors.identifier: http://orcid.org/0000-0002-7275-8297
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
authors.affiliation: Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark. mbn@chem.ku.dk.
authors.forename: Mogens Brøndsted
authors.identifier: http://orcid.org/0000-0001-8377-0788
authors.initials: MB
authors.lastname: Nielsen
keywords: electrocyclic reactions; energy conversion; macrocycles; photochromism; strained molecules