Affiliation:
1. Department of Organic Chemistry University of Geneva Quai Ernest Ansermet 30 1211 Geneva 4 Switzerland
2. Department of Physical Chemistry University of Geneva Quai Ernest Ansermet 30 1211 Geneva 4 Switzerland
3. Dipartimento di Chimica e Chimica Industriale University of Pisa Via G. Moruzzi 13 56124 Pisa Italy
4. Laboratoire de Cristallographie University of Geneva Quai Ernest Ansermet 24 1211 Geneva 4 Switzerland
Abstract
AbstractA chiral bispyrene macrocycle designed for exclusive intermolecular excimer fluorescence upon aggregation was synthesized by a double hydrothiolation of a bis‐enol ether macrocycle followed by intramolecular oxidation of free thiols. Unusually high stereoselectivity was achieved for the thiol‐ene additions under templated conditions and Et3B/O2 radical initiation. After enantiomer separation (chiral stationary phase HPLC), aqueous conditions provoked aggregation. Detailed structural evolution was afforded by ECD/CPL monitoring. Three regimes can be observed and characterized by strong modifications in chiroptical patterns under, at, or above a 70 % H2O : THF threshold. In luminescence, high glum dissymmetry factors values were obtained, up to 0.022, as well as a double sign inversion of CPL signals during the aggregation, a behavior rationalized by time‐dependent density functional theory (TDDFT) calculations. Langmuir layers of enantiopure disulfide macrocycles were formed at the air–water interface and transferred onto solid substrates to afford Langmuir–Blodgett films, which were then studied by AFM and UV/ECD/fluorescence/CPL.
Funder
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Université de Genève