Charge-assisted chalcogen bonding in 2-(4-substituted benzoyl)thiazolo[3, 2-a]pyridin-4-ium bromides. (January 2022)

• Record Type: Journal Article
• Authors: Guseinov, Firudin I.; Malinnikov, Vladislav M.; Lialin, Kirill N.; Kobrakov, Konstantin I.; Shuvalova, Elena V.; Nelyubina, Yulia V.; Ugrak, Bogdan I.; Kustov, Leonid M.; Mahmudov, Kamran T.
• Is Part Of: Dyes and pigments. Volume 197(2022)
• Publication Date: 2022-01
• Subjects: Chalcogen bonding -- Noncovalent interactions -- α-bromacetals -- β-ketoacetals -- Thiazolo[3, 2-a]pyridines; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2021.109898
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: A series of 2-(4-substituted benzoyl)thiazolo[3, 2- a ]pyridin-4-ium bromides [−OCH3 (1 ), –H (2 ), –F (3 ), −Cl (4 )] was obtained by the heterocyclization reaction of the corresponding 2-bromo-1-(4-substituted phenyl)-3, 3-diethoxypropan-1-ones with pyridine-2-thiol in dry isopropyl alcohol under reflux for 2 h. The new compounds 1 –4 were characterized by elemental analysis, 1 H and 13 C NMR spectroscopy and single crystal X-ray diffraction. Both the negative charge-assisted (S⋯ Br − ) and normal (S··· π) chalcogen bonds were found in the crystal packing of 2 −4, whereas one of the hydrogen atoms of an electron-donating –OCH3 group in 1, behaves as a bifurcated hydrogen bond donor centre towards a sulfur atom of the thiazolo ring and an oxygen atom of CO group of a neighboring molecule leading to the intermolecular hydrogen bonds. The optical properties of 1 −4 in DMSO, DMF and MeOH were investigated by UV–vis absorption spectroscopy, with λ max being dependent on the solvent polarity and attached substituents (−OCH3, –H, –F, −Cl) at the para- position of the aromatic moiety. Graphical abstract: Image 1 Highlights: Charge assisted chalcogen bonding. Synthesis of thiazolo[3, 2- a ]pyridines. Solvent and substituent effects on the absorption spectra of thiazolo[3, 2- a ]pyridines.