Synthesis, acid-base responsive fluorescence, and ion-selectivity of novel π-conjugated polymers containing coumarin unit in the main chain

• Published in: Polymer (Guilford) Vol. 294; p. 126729
• Main Authors: Kaneko, Yuya, Wang, Aohan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 16.02.2024
• Subjects: acid-base responsive fluorescence; Ion selectivity; π-conjugated polymer containing coumarin unit in the main chain; acid-base responsive fluorescence; π-conjugated polymer containing coumarin unit in the main chain; Ion selectivity
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2024.126729

A two-step synthetic method for four dibromocoumarin monomers (3,7-dibromo-4-methylcoumarin, 3, 6-dibromo-4-methylcoumarin, 3,7-dibromocoumarin, and 3,6-dibromocoumarin) containing von Pechmann reaction for the formation of coumarin ring followed by regioselective bromination at C3 position at monobrominated coumarins was developed. A series of novel coumarin-fluorene π-conjugated copolymers was synthesized by Sonogashira coupling reaction. The polymers exhibited absorption maxima at longer wavelength due to π-π* transition of the main chain, which indicates the expansion of π-conjugated system along the polymer main chain. The polymers showed acid-base responsive fluorescence due to the lactone ring opening-closing property in the main chain accompanied by the addition of alkali and acid. The polymers also exhibited ion selectivity between Na+ and K+ ion. [Display omitted] •Synthesis of novel π-conjugated polymers containing coumarin unit in the mainchain.•A two-steps synthesis for dibromocoumarin monomers was developed.•Coumarin-based π-conjugated polymers showed acid-base responsive fluorescence.•Coumarin-based π-conjugated polymers showed Na+/K+ ion selectivity.