Conjugated copolymers bearing 2, 7-di(thiophen-2-yl)phenanthrene-9, 10-dione units and alteration of their emission via functionalization of the ortho-dicarbonyl groups into quinoxaline and phenazine derivatives. (12th September 2019)

• Record Type: Journal Article
• Authors: Alameddine, Bassam; Baig, Noorullah; Shetty, Suchetha; Al-Mousawi, Saleh
• Is Part Of: Polymer. Volume 178(2019)
• Publication Date: 2019-09-12
• Subjects: Reactive polymers -- Conjugated polymers -- Gel permeation chromatography (GPC) -- Fluorescence; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2019.121589
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: Conjugated copolymers were prepared from 2, 7-di(thiophen-2-yl)phenanthrene-9, 10-dione units with various polycyclic aromatic hydrocarbon moieties, namely, fluorene (PQF1-2 ), carbazole (PQC ), and silafluorene (PQS ). Employing mild condensation reaction conditions, PQF1-2 copolymers underwent post-modification of their ortho -dicarbonyl groups into quinoxaline- (PQF3-4 ) and phenazine- (PQF5-6 ) derivatives. The copolymersPQF1-6, PQC, and PQS were characterized by different analytical techniques, such as, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), 1 H- and 13 C nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), UV–vis absorption, and emission spectroscopy. Post-modification of copolymersPQF1-2 led to interesting changes in the emission properties where the quinoxaline-containing copolymersPQF3-4 portrayed a 20–40 nm hypsochromic shift with a blue emission (~470 nm) whereas copolymersPQF5-6 bearing the more aromatically extended phenazine-units revealed a ~55 nm bathochromic shift displaying a green emission (~560 nm). Graphical abstract: Image 1 Highlights: Conjugated polymers were synthesized from phenanthrene-9, 10-dione, thiophene, and various PAHs. Copolymers underwent post-modification of their ortho -dicarbonyl groups into quinoxaline- and phenazine derivatives. TGA analysis shows high 10% weight loss temperatures (Td ) of the copolymers reaching up to 410 ᵒ C. Copolymers with quinoxaline groups display a blue emission whereas those with phenazine units reveal a green emission.