title: Nitrogen heterocyclic carbon-rich materials: synthesis and spectroscopic properties of dehydropyridoannulene macrocycles.
abstract: A new series of nitrogen heterocyclic dehydroannulenes 1-3 have been synthesized and their macrocyclic structures assigned using spectroscopic methods. The chiral and planar ground state conformations of 1 and 3, respectively, were determined by semiempirical theoretical calculations. All dehydropyridoannulenes and precursors possessing four aromatic rings functioned as fluorescent chromophores. A detailed spectroscopic investigation into the cation-binding properties of 3 in dilute solution revealed a particularly selective photoluminescence quenching sensory response for Pd(II) ions. Cycle 3, as well as 1 and 2, also exhibited reversible proton-triggered luminescence quenching behavior. At higher concentrations, 3 afforded a coordination polymer precipitate with Ag(I) ions. Cycles 1 and 2 and precursors 15, 23, and 29 also undergo thermochemical reactions that may potentially lead to carbon-rich polymers. The physicochemical properties of 1-3 suggest that dehydropyridoannulenes may serve as a particularly versatile new class of ligands for the creation of novel heteroatom-containing carbon-rich materials with many potential applications in supramolecular materials science and nanotechnology.
authors.affiliation: Institut Charles Sadron, UPR 022, 6 Rue Boussingault, F-67083 Strasbourg, France. baxter@ics.u-strasbg.fr
authors.forename: Paul N W
authors.initials: PN
authors.lastname: Baxter
authors.forename: Riad
authors.initials: R
authors.lastname: Dali-Youcef