Use of tertiary solvent mixtures to study solvent effects

Beschreibung

The physical properties of the solvent influence the rate constant of Photoinduced electron transfer (PET) reactions in many ways. Dielectric constant ε and refractive index n influence the solvent dipole reorientations and contribute to the activation energy of the ET reactions [1]. Electron-transfer kinetics is also influenced by diffusion and therefore by the solvent viscosity η. Unfortunately, most measurements published use different solvents in a not consequent way [2].
We present here the results of experiments made in a series of solvent mixtures comprising propyl acetate (PA), butyronitrile (BN), and diethyl phthalate (DEP), spanning a wide range of dielectric constants, keeping the n and η constant [3]. We used the PET reaction of singlet excited pyrene and indole whose solvent dependence is already described in the literature [2]. Quenching rate constants were obtained from Stern-Volmer plots based on both static and dynamic (TCSPC) measurements. The ΔG-dependence of ln kq are reported for the solvent mixtures and compared with results reported in pure organic solvents [2].

[1] M. Berghold, J. Bächle, S. Landgraf, G. Grampp, ChemPhysChem, 18,128 (2017).
[2] H. A. Montejano, J.J. Cosa, H.A. Garrera, C.M. Previtali, J. Photochem. Photobiol. A Chem. 86,115 (1995).
[3] A. Wankmüller, M. Berghold, S. Landgraf, J. Mol. Liquids, 333, 115880 (2021).

Zeitraum	18 Juli 2022 → 19 Juli 2022
Ereignistitel	28th PhotoIUPAC Amsterdam 2022 Symposium
Veranstaltungstyp	Konferenz
Ort	Amsterdam, NiederlandeAuf Karte anzeigen
Bekanntheitsgrad	International