New non-conjugated luminescent glycol-terephthalate oligomers bearing aryl Schiff bases: Chemical functionalization, chemical-optical characterization, thermal behavior and fluorescent sensing properties

In this paper, new non-conjugated luminescent glycol-terephthalate oligomers were obtained by means of free radical reaction between glycol-terephthalate oligomers and the corresponding aryl Schiff bases. This route demonstrated to be a better strategy than ionizing or plasma treatments in terms of processing facility, short reaction time, reproducibility and added value of resulting fluorescent materials. All compounds were characterized by NMR, IR/ATR, TGA-DTA, GPC, MALDI-TOF-MS, and XPS techniques. The thermal behavior for the functionalized oligomers was also studied. The optical properties of functionalized oligomers and the aryl Schiff bases have been determined and display fluorescent quantum yields below 6.24%. In a preliminary carbon dioxide sensing test, the anthracenyl oligomer showed a good linearity (R2 = 0.928) with a limit of detection and quantification of 415 and 1258 μM, respectively. To the best of our knowledge, this is the first report on the preparation of luminescent glycol-terephthalate oligomers for the fluorescent sensing of carbon dioxide.