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- Title
Giant Shape‐Persistent Tetrahedral Porphyrin System: Light‐Induced Charge Separation.
- Authors
Marchini, Marianna; Luisa, Alessandra; Bergamini, Giacomo; Armaroli, Nicola; Ventura, Barbara; Baroncini, Massimo; Demitri, Nicola; Iengo, Elisabetta; Ceroni, Paola
- Abstract
Tetraphenylmethane appended with four pyridylpyridinium units works as a scaffold to self‐assemble four ruthenium porphyrins in a tetrahedral shape‐persistent giant architecture. The resulting supramolecular structure has been characterised in the solid state by X‐ray single crystal analysis and in solution by various techniques. Multinuclear NMR spectroscopy confirms the 1 : 4 stoichiometry with the formation of a highly symmetric structure. The self‐assembly process can be monitored by changes of the redox potentials, as well as by modifications in the visible absorption spectrum of the ruthenium porphyrin and by a complete quenching of both the bright fluorescence of the tetracationic scaffold and the weak phosphorescence of the ruthenium porphyrin. An ultrafast photoinduced electron transfer is responsible for this quenching process. The lifetime of the resulting charge separated state (800 ps) is about four times longer in the giant supramolecular structure compared to the model 1 : 1 complex formed by the ruthenium porphyrin and a single pyridylpyridinium unit. Electron delocalization over the tetrameric pyridinium structure is likely to be responsible for this effect.
- Subjects
PORPHYRINS; PHOTOINDUCED electron transfer; ELECTRON delocalization; REDUCTION potential; ABSORPTION spectra; PHOSPHORESCENCE spectroscopy
- Publication
Chemistry - A European Journal, 2021, Vol 27, Issue 65, p16250
- ISSN
0947-6539
- Publication type
Article
- DOI
10.1002/chem.202102135