Synthesis of Macrocyclic Receptors with Intrinsic Fluorescence Featuring Quinizarin Moieties

An unprecedented class of macrocycles
with intrinsic fluorescence
consisting of phenolic trimers and quinizarin is developed. Though
they are lacking strong hydrogen bonds as observed in calixarenes,
the two examples introduced here each adopt a vase-like conformation
with all four aromatic units pointing in one direction (syn orientation). This “cone” conformation has been confirmed
by NMR spectroscopy, molecular modeling, and X-ray crystallography.
The laminar, electron-rich fluorophore as part of the macrocycle allows
additional contacts to enclosed guest molecules.