TY - JOUR

T1 - Long-Term Energy Storage Systems Based on the Dihydroazulene/Vinylheptafulvene Photo-/Thermoswitch

AU - Schøttler, Christina

AU - Vegge, Siri Krogh

AU - Cacciarini, Martina

AU - Nielsen, Mogens Brøndsted

N1 - Funding Information: MIUR - progetto Dipartimenti di Eccellenza2018–2022 (ref. B96C1700020008) and Centro Interdipartimentale Risonanza Magnetica (C.I.R.M.) are acknowledged for financial support. Funding Information: MIUR ‐ progetto Dipartimenti di Eccellenza2018–2022 (ref. B96C1700020008) and Centro Interdipartimentale Risonanza Magnetica (C.I.R.M.) are acknowledged for financial support. Publisher Copyright: © 2022 The Authors. ChemPhotoChem published by Wiley-VCH GmbH.

PY - 2022

Y1 - 2022

N2 - The dihydroazulene/vinylheptafulvene (DHA/VHF) couple presents a photo-/thermoswitch that has attracted interest for the development of molecular solar thermal energy storage systems. Here we present the synthesis and optical properties as well as the switching properties of DHA derivatives incorporating alkyne and norbornadiene (NBD) substituents at position C2. The corresponding VHF isomers exhibited remarkably long lifetimes. Thus, the VHF-to-DHA back-reaction half-life for a derivative with a phenylethynyl substituent was 22 days in acetonitrile at room temperature, while the half-life of a VHF reference compound having a phenyl substituent is around 3.5 h under the same conditions. This finding is particularly attractive in the quest for long-term energy storage systems, considering limited enhancement of molecular weight and maintenance of good quantum yield photoisomerization. Moreover, from the thermal back-reaction of an NBD compound, used as a precursor for the DHA-NBD dyad, we estimated the radical-stabilizing influence of a C(Me)=C(CN)2 substituent.

AB - The dihydroazulene/vinylheptafulvene (DHA/VHF) couple presents a photo-/thermoswitch that has attracted interest for the development of molecular solar thermal energy storage systems. Here we present the synthesis and optical properties as well as the switching properties of DHA derivatives incorporating alkyne and norbornadiene (NBD) substituents at position C2. The corresponding VHF isomers exhibited remarkably long lifetimes. Thus, the VHF-to-DHA back-reaction half-life for a derivative with a phenylethynyl substituent was 22 days in acetonitrile at room temperature, while the half-life of a VHF reference compound having a phenyl substituent is around 3.5 h under the same conditions. This finding is particularly attractive in the quest for long-term energy storage systems, considering limited enhancement of molecular weight and maintenance of good quantum yield photoisomerization. Moreover, from the thermal back-reaction of an NBD compound, used as a precursor for the DHA-NBD dyad, we estimated the radical-stabilizing influence of a C(Me)=C(CN)2 substituent.

KW - alkynes

KW - conjugation

KW - cycloaddition

KW - electrocyclic reactions

KW - photochromism

U2 - 10.1002/cptc.202200037

DO - 10.1002/cptc.202200037

M3 - Journal article

AN - SCOPUS:85129840961

VL - 6

JO - ChemPhotoChem

JF - ChemPhotoChem

SN - 2367-0932

IS - 8

M1 - e202200037

ER -