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A Highly Luminescent Tetramer from a Weakly Emitting Monomer: Acid‐ and Redox‐Controlled Multiple Complexation by Cucurbit[7]uril
Author(s) -
Bergamini Giacomo,
Fermi Andrea,
Marchini Marianna,
Locritani Mirko,
Credi Alberto,
Venturi Margherita,
Negri Fabrizia,
Ceroni Paola,
Baroncini Massimo
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201400375
Subject(s) - tetramer , monomer , protonation , chemistry , molecule , luminescence , density functional theory , redox , fluorescence , photochemistry , crystallography , absorption (acoustics) , computational chemistry , inorganic chemistry , materials science , polymer , organic chemistry , ion , physics , optoelectronics , quantum mechanics , composite material , enzyme
The tetrahedral, shape‐persistent molecule 1 4+ , containing four pyridylpyridinium units connected through a central carbon atom, exhibits unexpected photophysical properties including a substantially redshifted absorption (2350 cm −1 ) and a very strong fluorescence ( Φ em =40 %), compared with the monomer 2 + ( Φ em =0.4 %). Density functional theory calculations on the structure and spectroscopic properties of 1 4+ and 2 + show that exciton interactions, homoconjugation, and orbital nature account for the observed differences in their photophysical properties. The protonated tetramer binds four cucurbit[7]uril molecules and the host/guest interactions can be controlled by chemical (acid/base) as well as redox stimuli.