Skip to Main content Skip to Navigation
Journal articles

Photoinduced Intercomponent Processes in Selectively Addressable Bichromophoric Dyads Made of Linearly Arranged Ru(II) Terpyridine and Expanded Pyridinium Components

Abstract : Three new linearly arranged bichromophoric systems 1–3 have been prepared, and their photophysical properties have been studied, taking also advantage of femtosecond pump–probe transient absorption spectroscopy. The three compounds contain the same chromophores, that is a Ru(II)-terpy-like species and a fused expanded bipyridinium (FEBP) unit, separated by three different, variously methylated biphenylene-type bridges. The chromophores have been selected to be selectively addressable, and excitation involving the Ru-based or the FEBP-based dyes results in different excited-state decays. Upon Ru-based excitation at 570 nm, oxidative photoinduced electron transfer (OPET) takes place in 1–3 from the 3MLCT state; however, the charge-separated species does not accumulate, indicating that the charge recombination rate constant exceeds the OPET rate constant. Upon excitation of the organic dye at 400 nm, the FEBP-based 1π–π* level is prepared, which undergoes a series of intercomponent decay events, including (i) electron-exchange energy transfer leading to the MLCT manifold (SS-EnT), which successively decays according to 570 nm excitation, and (ii) reductive photoinduced electron transfer (RPET), leading to the preparation of the charge-separated (CS) state. Reductive PET, involving the FEBP-based singlet state, is much faster than oxidative PET, involving the MLCT triplet state, essentially because of driving force reasons. The rate constant of CR is intermediate between the rate constants of OPET and RPET, and this makes 1–3 capable to selectively read the 400 nm excitation as an active input to prepare the CS state, whereas excitation at wavelengths longer than 480 nm is inefficient to accumulate the CS state. Moreover, intriguing differences between the rate constants of the various processes in 1–3 have been analyzed and interpreted according to the superexchange theory for electron transfer. This allowed us to uncover the role of the electron-transfer and hole-transfer superexchange pathways in promoting the various intercomponent photoinduced decay processes occurring in 1–3.
Document type :
Journal articles
Complete list of metadatas

Cited literature [35 references]  Display  Hide  Download

https://hal-univ-paris.archives-ouvertes.fr/hal-02399088
Contributor : Philippe Lainé <>
Submitted on : Sunday, December 8, 2019 - 7:36:07 PM
Last modification on : Wednesday, October 14, 2020 - 3:58:39 AM
Long-term archiving on: : Monday, March 9, 2020 - 1:54:05 PM

File

ic201900139x_revised.pdf
Files produced by the author(s)

Identifiers

Citation

Fausto Puntoriero, Antonino Arrigo, Antonio Santoro, Giuseppina La Ganga, Fabien Tuyèras, et al.. Photoinduced Intercomponent Processes in Selectively Addressable Bichromophoric Dyads Made of Linearly Arranged Ru(II) Terpyridine and Expanded Pyridinium Components. Inorganic Chemistry, American Chemical Society, 2019, 58 (9), pp.5807-5817. ⟨10.1021/acs.inorgchem.9b00139⟩. ⟨hal-02399088⟩

Share

Metrics

Record views

268

Files downloads

792