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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY, cilt.158, ss.493-516, 2026 (SCI-Expanded, Scopus)
In this study, a series of naphthalene-tethered Schiff bases and their corresponding poly(phenoxy-imine) derivatives were synthesized through condensation and oxidative polycondensation reactions. Quantitative comparison revealed that only SB2 exhibited a remarkable 28-fold enhancement in fluorescence intensity upon coordination with Sn2+ ions, ascribed to by a chelation-enhanced fluorescence (CHEF) mechanism accompanied by the suppression of -C=N- isomerization. The chemosensor exhibited excellent selectivity, a low detection limit of 45 nM, and a high association constant (2.86 & times; 10(10) M-2). Moreover, Interference experiments performed with competing metal (Ag+, K+, Cd2+, Co2+, Cu2+, Hg2+, Mn2+, Ni2+, Pb2+, Zn2+, Al3+, Cr3+, Fe3+, and Cr6+) five times greater than that of SB2 confirmed the selectivity of its sensing performance. All poly(phenoxy-imine)s displayed substantial char yields and high limiting oxygen index (LOI) values, indicating their potential as impressive flame-retardant properties (LOI > 33 %). Furthermore, polymers P-SB1 and P-SB2 displayed blue and violet photoluminescence, respectively, under UV excitation, suggesting their utility in light-emitting materials. The novelty of this work lies in the integration of a highly selective "turn-on" fluorescent chemosensor (SB2) for Sn2+ ions with the synthesis of thermally stable, flame-retardant poly(phenoxy-imine)s, establishing a new class of multifunctional materials that combine environmental sensing capability with exceptional thermal and optical performance. Graphical abstract Synthesis and characterization of naphthalene-tethered Schiff bases and corresponding poly(phenoxy-imine)s: A potent and highly selective "turn-on" chemosensor for Sn2+ ions.