Abstract
A theoretical and experimental investigation of conformational modifications on the
thermodynamic, optical, and switching properties of dihydroazulene/vinylheptafulvene
(DHA/VHF) photoswitches, in the context of molecular solar thermal (MOST) systems, is
described herein. The optical properties of monomeric DHA/VHF systems are found to be
strongly dependent on structural changes which can be tuned via steric modifications. This
correlation is then used to infer structural features of more complex, macrocyclic DHA/VHF
systems based on their optical properties. The introduction of macrocyclic ring strain is
furthermore found to significantly influence the switching behavior of DHA/VHF moieties
compared to non-cyclized systems. The thermal ring closure of macrocyclic VHF-VHF systems
is found to occur in a stepwise manner, enabling the release of the energy on both a fast and slow
timescale, hypothetically addressing both immediate and long-term energy discharge
requirements.
The incorporation of an azobenzene (AZB) moiety in a macrocyclic system imparts higher
rigidity compared to analogs including alkyl chains, indicating increased ring strain in the
ground (DHA-DHA) state relative to the metastable (VHF-VHF) state. The AZB is then shown
to function as an orthogonal switch to trigger energy release from the metastable to the ground
state, enhancing the reaction 3-fold. Lastly, the multimode switching potential of several
ruthenium alkynyl DHA ([Ru*]-DHA) systems is elucidated through a variety of
spectroelectrochemical techniques demonstrating, for one analog, complete six-state switching
behavior.
thermodynamic, optical, and switching properties of dihydroazulene/vinylheptafulvene
(DHA/VHF) photoswitches, in the context of molecular solar thermal (MOST) systems, is
described herein. The optical properties of monomeric DHA/VHF systems are found to be
strongly dependent on structural changes which can be tuned via steric modifications. This
correlation is then used to infer structural features of more complex, macrocyclic DHA/VHF
systems based on their optical properties. The introduction of macrocyclic ring strain is
furthermore found to significantly influence the switching behavior of DHA/VHF moieties
compared to non-cyclized systems. The thermal ring closure of macrocyclic VHF-VHF systems
is found to occur in a stepwise manner, enabling the release of the energy on both a fast and slow
timescale, hypothetically addressing both immediate and long-term energy discharge
requirements.
The incorporation of an azobenzene (AZB) moiety in a macrocyclic system imparts higher
rigidity compared to analogs including alkyl chains, indicating increased ring strain in the
ground (DHA-DHA) state relative to the metastable (VHF-VHF) state. The AZB is then shown
to function as an orthogonal switch to trigger energy release from the metastable to the ground
state, enhancing the reaction 3-fold. Lastly, the multimode switching potential of several
ruthenium alkynyl DHA ([Ru*]-DHA) systems is elucidated through a variety of
spectroelectrochemical techniques demonstrating, for one analog, complete six-state switching
behavior.
| Originalsprog | Engelsk |
|---|
| Forlag | Department of Chemistry, Faculty of Science, University of Copenhagen |
|---|---|
| Antal sider | 188 |
| Status | Udgivet - 2017 |