Dataset Information

Solution-phase molecular recognition of an azafullerene-quinoline dyad by a face-to-face porphyrin-dimer tweezer.

ABSTRACT: A face-to-face porphyrin dimer, (H₂P)₂ "porphyrin tweezer", was explored as a photo- and redox-responsive host for the molecular recognition of an azafullerene (C₅₉N) derivative bearing an amphoteric pentafluoroquinoline (FQ) domain. The intramolecular electronic coupling between the FQ substituent and the C₅₉N cage, within the newly synthesized C₅₉N-FQ dyad was evaluated, while the neutral and protonated form of the covalently attached FQ moiety were utilized as recognition motifs for the (H₂P)₂ tweezer. Complementary photophysical and electrochemical techniques were applied to investigate the electronic communication between the porphyrin-dimer (H₂P)₂ tweezer and the azafullerene cage as mediated by the FQ unit.

SUBMITTER: Stergiou A

PROVIDER: S-EPMC9056541 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Solution-phase molecular recognition of an azafullerene-quinoline dyad by a face-to-face porphyrin-dimer tweezer.

Stergiou Anastasios A Andreopoulou Aikaterini K AK Kallitsis Joannis K JK Tagmatarchis Nikos N

RSC advances 20200827 53

A face-to-face porphyrin dimer, (H2P)2 "porphyrin tweezer", was explored as a photo- and redox-responsive host for the molecular recognition of an azafullerene (C59N) derivative bearing an amphoteric pentafluoroquinoline (FQ) domain. The intramolecular electronic coupling between the FQ substituent and the C59N cage, within the newly synthesized C59N-FQ dyad was evaluated, while the neutral and protonated form of the covalently attached FQ m ...[more]

PMID: 35518168

Similar Datasets

Project description:The dynamics of electron and spin transfer in the radical cation and photogenerated triplet states of a tetramethylbiphenyl-linked zinc-porphyrin dimer were investigated, so as to test the relevant parameters for the design of a single-molecule spin valve and the creation of a novel platform for the photogeneration of high-multiplicity spin states. We used a combination of multiple techniques, including variable-temperature continuous wave EPR, pulsed proton electron-nuclear double resonance (ENDOR), transient EPR, and optical spectroscopy. The conclusions are further supported by density functional theory (DFT) calculations and comparison to reference compounds. The low-temperature cw-EPR and room-temperature near-IR spectra of the dimer monocation demonstrate that the radical cation is spatially localized on one side of the dimer at any point in time, not coherently delocalized over both porphyrin units. The EPR spectra at 298 K reveal rapid hopping of the radical spin density between both sites of the dimer via reversible intramolecular electron transfer. The hyperfine interactions are modulated by electron transfer and can be quantified using ENDOR spectroscopy. This allowed simulation of the variable-temperature cw-EPR spectra with a two-site exchange model and provided information on the temperature-dependence of the electron transfer rate. The electron transfer rates range from about 10.0 MHz at 200 K to about 53.9 MHz at 298 K. The activation enthalpies Δ‡H of the electron transfer were determined as Δ‡H = 9.55 kJ mol-1 and Δ‡H = 5.67 kJ mol-1 in a 1:1:1 solvent mixture of CD2Cl2/toluene-d8/THF-d8 and in 2-methyltetrahydrofuran, respectively, consistent with a Robin-Day class II mixed valence compound. These results indicate that the interporphyrin electronic coupling in a tetramethylbiphenyl-linked porphyrin dimer is suitable for the backbone of a single-molecule spin valve. Investigation of the spin density distribution of the photogenerated triplet state of the Zn-porphyrin dimer reveals localization of the triplet spin density on a nanosecond time scale on one-half of the dimer at 20 K in 2-methyltetrahydrofuran and at 250 K in a polyvinylcarbazole film. This establishes the porphyrin dimer as a molecular platform for the formation of a localized, photogenerated triplet state on one porphyrin unit that is coupled to a second redox-active, ground-state porphyrin unit, which can be explored for the formation of high-multiplicity spin states.

Dataset Information

Solution-phase molecular recognition of an azafullerene-quinoline dyad by a face-to-face porphyrin-dimer tweezer.

Publications

Solution-phase molecular recognition of an azafullerene-quinoline dyad by a face-to-face porphyrin-dimer tweezer.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets