BMOLogo
Publications

LMU München
Fakultät für Physik


Home

General
Research
Funding
Members
Publications
  All Publications
  PhD Theses
  Master Theses
  Search
  i Search
Lectures/Seminars
Conferences
Vacancies
Search

Internal




Impressum
(c) 2002 BMO

"Excited-state dynamics of a molecular dyad with two orthogonally-oriented fluorophores"
R. Letrun, B. Lang, O. Yushchenko, R. Wilcken, D. Svechkarev, D. Kolodieznyi, E. Riedle, and E. Vauthey
Phys. Chem. Chem. Phys., 20, 30219 - 30230 (2018)


Abstract:
The excited-state dynamics of a T-shaped bichromophoric molecule, consisting of two strong fluorophores, diphenyloxazole and diphenylpyrazoline, directly linked in an orthogonal geometry, was investigated. Despite the weak coupling ensured by this geometry and confirmed by the electronic absorption spectra, this dyad exhibits only weak fluorescence in both apolar and polar solvents, with fluorescence lifetimes ranging from 200 ps in CHX to 10 ps in ACN. Ultrafast spectroscopic measurements reveal that the fluorescence quenching in polar solvents is due to the population of a charge-separated state. In non-polar solvents, this process is energetically not feasible, and a quenching due to an efficient intersystem crossing (ISC) to the triplet manifold is proposed, based on quantum-chemical calculations. This process occurs via the spin-orbit charge-transfer (SOCT) ISC mechanism, which is enabled by the charge-transfer character acquired by the S1 state of the dyad upon structural relaxation and by the orthogonal arrangement of the molecular orbitals involved in the transition. The same mechanism is proposed to explain why the recombination of the charge-separated state is faster in medium than in highly polar solvents, as well as to account for the fast decay of the lowest triplet state to the ground state.

BMO authors (in alphabetic order):
Eberhard Riedle
Roland Wilcken

Order Hardcopy

WWW-Version

DOI-Version

mailto: webmaster
Letzte Änderung: 2016-09-14 13:34