Synthesis, structural characterization and chromatic features of new 2-phenyl-1-benzopyrylium and 2-phenyl-styryl-1-benzopyrylium amino-based blue dyes

• Type: Article in International Scientific Journal
• Date: 2021

Authors

Araujo, P (Author) Other; Victor de Freitas (Author) FCUP; de Freitas, V (Author) Other; Nuno Mateus (Author) FCUP; Iva Fernandes (Author) FCUP; Joana Oliveira (Author) FCUP

Journal

Title: Tetrahedron Letters

Vol. 85

ISSN: 0040-4039

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 9 Citations

Scopus - 9 Citations

Other information

Authenticus ID: P-00V-MQD

DOI: 10.1016/j.tetlet.2021.153487

Abstract (EN): Six new amino-based flavylium dyes (5,7OH(2)4'NMe2, 5,7OH(2)st4'NMe2, 7NEt(2)4'NMe2, 7NEt(2)st4'NMe2, 7NEt(2)4'NH2 and 7NEt(2)4'OH) were synthesized through acidic aldolic condensation reaction between 2,4,6-trihydroxybenzaldehyde or 4-diethylaminosalysaldehyde with different acetophenones (4-amino-, 4-dimethylamino-, 4-hydroxyl-acetophenone or p-dimethylstyrylmethylketone). The obtained amino-based dyes were structurally characterized by LC-MS and NMR analysis. It was demonstrated that the nature and position of the functional groups attached to the 2-phenyl-1-benzopyrylium core and the presence/absence of a 2-styryl linkage in the benzopyrylium moiety are responsible for a different electronic delocalization contributing to the different color displayed by each dye. Compounds presenting a 2-styryl linkage (5,7OH(2)st4'NMe2 and 7NEt(2)st4'NMe2) have a higher maximum absorption wavelength (636 nm and 675 nm, respectively), probably resulting from their extended electronic delocalization. On the other hand, the presence of stronger electron donating groups such as dimethyl- or diethyl-amino leads to a bathochromic shift in the maximum absorption wavelength of dyes when compared to the ones presenting hydroxyl groups or a primary amine.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 5