Addressing Charge-Transfer and Locally-Excited States in a Twisted Biphenyl Push-Pull Chromophore

Elisa Campioli (1) , Somananda Sanyal (1) , Agnese Marcelli (2) , Mariangela Di Donato (2) , Mireille Blanchard-Desce (3) , Olivier Mongin (4) , Anna Painelli (1) , Francesca Terenziani (1)

1 UNIPR - Università degli studi di Parma = University of Parma
2 LENS - European Laboratory for Non-Linear Spectroscopy
3 ISM - Institut des Sciences Moléculaires
4 ISCR - Institut des Sciences Chimiques de Rennes

We present the synthesis and spectroscopic characterization of a twisted push-pull biphenyl molecule undergoing photoinduced electron transfer. Steady-state and transient absorption spectra suggest, in this rigid molecular structure, a subtle interplay between locally-excited and charge-transfer states, whose equilibrium and dynamics is only driven by solvation. A theoretical model is presented for the solvation dynamics and, with the support of quantum chemical calculations, we demonstrate the existence of two sets of states, having either local or charge-transfer character, that only "communicate" thanks to solvation, which is the sole driving force for the charge-separation process.

Mots clés: dual fluorescence; electron transfer; solvation dynamics; theoretical modelling; time-resolved spectroscopy

Domaines: Chimie

Elisa Campioli, Somananda Sanyal, Agnese Marcelli, Mariangela Di Donato, Mireille Blanchard-Desce, et al.. Addressing Charge-Transfer and Locally-Excited States in a Twisted Biphenyl Push-Pull Chromophore. ChemPhysChem, 2019, 20 (21), pp.2860-2873. ⟨10.1002/cphc.201900703⟩. ⟨hal-02307078⟩