Details

Autor(en) / Beteiligte

• Lanza, Priscila A.
• Dusso, Diego
• Mena, Leandro D.
• Parise, Alejandro R.
• Moyano, E. Laura
• Chesta, Carlos A.
• Vera, D. Mariano A.

Titel

Why and how could an aliphatic bridge allow for a long-range photoinduced charge separation in Tröger’s bases derivatives

Ist Teil von

• Journal of photochemistry and photobiology. A, Chemistry., 2023-07, Vol.441, p.114699, Article 114699

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• [Display omitted] •Unique Donor (D)-aliphatic linker-Acceptor (A) CT states are characterized in detail.•D-(σ linker)-A dyads can behave as typical D-π-A pull–push for Tröger’s base linker.•Homoconjugation and through-bond coupling play together causing charge separation.•The contribution of those factors depends upon the redox gap of the D and A centers.•Tuned CAM-B3LYP allowed an accurate calculation of absorption and emission energies. Tröger’s bases (TBs) have shown great potential to be used in different fields of science, such as biology, organic synthesis, photoelectronic applications, among others. As we have recently shown, a series of asymmetrically substituted Tröger’s base derivatives showed unexpected pull–push behavior. The aliphatic diazocine heterocycle which connect an electron donor and an electron acceptor moiety efficiently couples both electronic subsystems as if it were a typical π-conjugated linker. A thorough computational study was intended to shed light on the origin of the observed photophysical properties. A modified version of the CAM-B3LYP functional yielded an accurate prediction of the absorption and emission spectra of these species. In contrast, range-corrected and classical hybrid approaches showed too high and remarkably too low excited states energies, respectively. Unlike the typical π-linked donor/acceptor systems, a threshold was found in the redox gap of the centers in order to obtain a full charge separation. The role of the aliphatic bridge was found to be related to the unusual topology of the frontier orbitals involved, to the tension and particular molecular shape of the Tröger bicycle and to a contribution due to homoconjugation as well. Calculations on the actual Tröger derivatives and specific models were able to quantify the magnitude of the different contributions that make possible the charge separation.