PT Unknown
AU Raeker, T
TI Full-Dimensional Photodynamics Simulations:From Photoisomerizations to Excited-State Proton Transfer Reactions
PY 2018
PU Christian-Albrechts-Universität zu Kiel
WP https://macau.uni-kiel.de/receive/diss_mods_00023207
LA en
DE photodynamics; computer chemistry; proton transfer; switching; photoisomerization; azobenzene; Photodynamik; Computerchemie; Protontransfer; Schalten; Photoisomerisierung; Azobenzol
AB Photoactive molecules are studied for their electronic properties and are also being designed for use in specific applications or even molecular machines.
Two photochemical reactions are investigated in this thesis: trans<->cis photoisomerization (“switching”) and excited-state intramolecular proton transfer (ESIPT).
The first reaction type is represented by the newest generation of bridged-azobenzene derivatives, indandiazocine and diindandiazocine which were designed to achieve chiral trans→cis isomerization as an upgrade over their parent system diazocine. This predicted feature is validated by calculations of the actual photodynamics of these systems. In a second project, azobenzene and the three aforementioned bridged azobenzenes are used as motors in an artificial cilium that served as a prototype for a molecular particle transport machine. Full-dimensional calculations of the ESIPT dynamics of salicylic acid and several other derivatives are presented for the first time here, all featuring a so-called "crane-switching" motif.
With 7-hydroxy-4-methylquinoline-8-carbaldehyde (HMQCA) a more complex ESIPT system is also investigated which utilizes the crane-switching to allow for a PT to a different site of the
molecule than the initial proton donor. The computational model of choice for calculating the photodynamics is semiempirical quantum mechanics (SEQM) coupled to floating-occupation configuration interaction. SEQM relies on
parameters that are fitted to reproduce a set of molecular properties. However, the studied ESIPT systems – or excited-state properties in general – are not part of such a set. Hence, deficiencies were encountered when comparing the obtained results to the results of ab initio QM methods.
PI Kiel
ER