Self-assembly involving hydrogen bonds. Spectral properties and structure of supramolecular complexes of bis-aza-18-crown-6-containing dienones with alkanediammonium salts

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Vol. 402; p. 112801
• Main Authors: Fomina, Marina V., Kurchavov, Nikolai A., Freidzon, Alexandra Ya, Nuriev, Vyacheslav N., Vedernikov, Artem I., Strelenko, Yuri A., Gromov, Sergey P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2020
• Subjects: Bis-azacrown-containing dienones; Electronic spectroscopy; Hydrogen-bonded complexes; NMR spectroscopy; Quantum chemical calculations; Stability constants; Bis-azacrown-containing dienones; Stability constants; NMR spectroscopy; Quantum chemical calculations; Electronic spectroscopy; Hydrogen-bonded complexes
• ISSN: 1010-6030
• DOI: 10.1016/j.jphotochem.2020.112801

[Display omitted] •Complexation of bis-aza-18-crown-6-containing dienones with EtNH3+ and +H3N(CH2)nNH3+.•The stability constants of the supramolecular complexes are measured.•Structures of the complexes are confirmed by 1H NMR spectroscopy and DFT calculations.•Fluorescence is decreased in the presence of EtNH3+ and +H3N(CH2)nNH3+ (n = 2–8).•Fluorescence is enhanced in the presence of +H3N(CH2)nNH3+ (n = 9, 10, 12). Dienones (ketocyanine dyes) containing two aza-18-crown-6 ether residues were synthesized. The complex formation of these dyes with the EtNH3+ and +H3N(CH2)nNH3+ ions (n = 2–10, 12) in MeCN was studied by electronic and 1H NMR spectroscopy, including spectrophotometric and 1H NMR titration. It was found that homoditopic bis-azacrown dienones and alkanediammonium ions with a short polymethylene chain form 1:1, 2:2, and 1:2 complexes, whereas alkanediammonium ions with a long polymethylene chain form only pseudocyclic 1:1 complexes. The stability constants of the resulting complexes were determined (logK1:1 varies in the range from 2.74 to 5.62 [M–1], logK2:2 = 2.1 [M–1], and logK1:2 varies in the range from 2.03 to 2.96 [M–1]). The most stable complexes are formed by diammonium ions with a long polymethylene chain owing to simultaneous binding of both NH3+ groups to the azacrown ether residues of the dye. The structure of supramolecular complexes was confirmed by quantum chemical calculations.