Pyrenoimidazolyl-Benzaldehyde Fluorophores: Synthesis, Properties, and Sensing Function for Fluoride Anions

Abstract

Two structural isomers of (9 H -pyreno[4,5- d ]imidazol-10-yl)-benzaldehyde, with para and meta substitution patterns, were synthesized by condensation of 4,5-pyrenedione with terephthalaldehyde and isophthalaldehyde, respectively. These new pyrenoimidazole derivatives were characterized by single-crystal X-ray crystallography, UV–vis absorption spectroscopy, fluorescence spectroscopy, and cyclic voltammetry to elucidate their structural, solid-state packing, and electronic properties. Interactions of these compounds with fluoride anions in polar organic solvents (acetone and dimethyl sulfoxide) were investigated by NMR, UV–vis, and fluorescence techniques in conjunction with density functional theory calculations. UV–vis analysis showed that the binding of the two pyrenoimidazolyl benzaldehydes with fluoride anions resulted in significant colorimetric responses, while fluorescence studies showed that the para -pyrenoimidazolyl benzaldehyde behaved as an intramolecular charge transfer fluorescent probe, exhibiting ratiometric sensing performance to efficiently detect and quantify fluoride anions at the sub-millimolar level.

Synthesis and electronic properties of nitrogen-doped π-extended polycyclic aromatic dicarboximides with multiple redox processes

“…[37][38][39][40] In order to synthesize the novel family of electron-acceptor π-extended nine-ring-fused systems, we have used the innovative one-pot condensation method of aromatic 1,2diketones recently developed by Zhao and co-workers. 41,42 Thus, diketones 2-4 were selfcondensed in glacial acetic acid in the presence of an excess of ammonium acetate by heating overnight at 110 °C to yield the target molecules (naft-2-4, Scheme 1) after a purification step. The three novel electron acceptors share the same π-conjugated skeleton and differ only on the solubilizing chain at the imide nitrogen.…”

Carbazole sulfonamide-based macrocyclic receptors capable of selective complexation of fluoride ion

“…Interestingly, upon addition of other competitive anions like H 2 PO 4 − and CH 3 COO − (Fig. S13 and S15 † ), only the disappearance of two NH signals was observed for 1 (probably due to a rapid proton exchange process), 33 without meaningful chemical shift changes for other proton signals. These observations demonstrated no or very weak binding of 1 with these anions in this medium.…”

Comparative studies of the noncovalent interactions in the single‐crystal packing of pyrene, pyrene‐4,5‐dione, and pyrene‐4,5,9,10‐tetraone

“…[22,28] The keto groups in pyrene-4,5-dione and pyrene-4,5,9,10-tetraone can undergo further reactions to generate diverse K-region functionalized pyrenes and related pyrene-fused π-conjugated systems. [19,[29][30][31][32][33][34] In terms of electronic properties, the pyrene-4,5-dione and pyrene-4,5,9,10-tetraone cores are electron deficient, [35] which is in sharp contrast to the electrondonating nature of pyrene. [36,37] Their unique electronic properties play a vital role in dictating the supramolecular assembling behavior, particularly in their solid-state intermolecular packing properties.…”