2-Arylazo-1-vinylpyrroles: A Novel Promising Family of Reactive Dyes

• Published in: European Journal of Organic Chemistry 2006-09, Vol.2006 (17), p.4021-4033
• Main Authors: Trofimov, Boris A., Schmidt, Elena Yu, Mikhaleva, Al'bina I., Vasil'tsov, Alexander M., Zaitsev, Alexey B., Smolyanina, Natalia S., Senotrusova, Elena Yu, Afonin, Andrey V., Ushakov, Igor' A., Petrushenko, Konstantin B., Kazheva, Olga N., Dyachenko, Oleg A., Smirnov, Vladimir V., Schmidt, Alexander F., Markova, Marina V., Morozova, Ludmila V.
• Format: Article
• Language: English
• Subjects: 1-Vinylpyrroles; 2-Arylazo-1-vinylpyrroles; Azo coupling; Conformation; Copolymerization; Dyes
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.200600357

New reactive dyes, 2‐arylazo‐1‐vinylpyrroles, have been synthesized in 52–94 % yield by a modified azo coupling of readily accessible 1‐vinylpyrroles with arenediazonium hydrocarbonates in aqueous ethanol (≈3:1) at 0 °C. The λmax values for the UV/Vis absorption of the dyes ranges from 377.8–480.6 nm with log ϵ = 4.11–4.99, and this strongly depends on the substituent structure both in the pyrrole and the benzene ring, and is indicative of highly polarizable and tunable chromophores. X‐ray, 1H NMR spectroscopic and quantum chemical studies [B3LYP/6‐311 (d,p)] show the E,anti,anti isomer of the dyes to be the most stable under normal conditions. The dyes are reversibly protonated and complex to BF3 with a color change. Their copolymerization across the vinyl group affords intrinsically colored copolymers. They have also been shown to act as good ligands in the Pd‐catalyzed Heck alkene arylation. Thus, the properties of the novel dyes are promising for creating new molecular switches, memory and recording devices, acid‐base and metal sensors, as well as transition‐metal complex catalysts.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)