Fluorescence properties of 3-hydroxy-2-naphthoic acid-doped poly(methyl methacrylate) composites

Abstract

In the last decades, poly(methyl methacrylate) (PMMA) has been widely studied due to its outstanding mechanical, chemical, and physical properties. In this article, the PMMA composites doped with an excited state intramolecular proton transfer (ESIPT) compound 3-hydroxy-2-naphthoic acid (3HNA) are reported. The 3HNA-doped PMMA composites were synthesized by in situ polymerization and characterized by Fourier transform infrared spectra, ultraviolet absorption spectra, fluorescence spectra, and thermogravimetric analysis. The effect of 3HNA and various solvents on the fluorescent properties of the PMMA composites was systematically investigated. The results indicated that the emission spectra of the 3HNA-doped PMMA composites exhibited 3HNA dual emission. A violet emission was observed in 3HNA-doped PMMA composites containing nonpolar solvents or weak polar solvents, whereas the composites containing strong polar solvents exhibited a large Stokes-shifted green fluorescence, which was attributed to the ESIPT of 3HNA.

Luminescence Tuning of Layered Rare-Earth Hydroxides (LRHs, R = Tb, Y) Composites with 3-Hydroxy-2-naphthoic Acid and Application to the Fluorescent Detection of Al3+

“…Figure describes the FT-IR spectra of the LRH precursors and composites. For HNA (Figure a), the O–H stretching vibrations of the C–OH group appeared at 3284 cm –1 . A very strong band at 1665 cm –1 corresponded to the CO stretching vibrations of −COOH.…”

“…For HNA (Figure 2a), the O−H stretching vibrations of the C−OH group appeared at 3284 cm −1 . 47 A very strong band at 1665 cm −1 corresponded to the CO stretching vibrations of −COOH. The peaks at 1516 and 1467 cm −1 were assigned to the naphthalene ring C−C stretching vibrations.…”

Modulation of Solid-State Optical Properties of o-Hydroxynaphthoic Acids through Formation of Charge Transfer Cocrystals with TCNB

“…As shown in Figure , the fluorescence emission spectra of 2H1NA and 1H2NA under excitation at 270 nm show blue emission bands with peaks at 452 and 440 nm, respectively, which are attributed to the normal π → π* transition of the naphthalene units. In contrast, 3H2NA exhibits a strong green emission band at around 500 nm, which is assigned to the π → π* transition of an enol tautomer formed by an excited-state intramolecular proton transfer from the hydroxyl group to the carbonyl oxygen in 3H2NA . In comparison with the pristine donors, 2H1NA/TCNB and 1H2NA/TCNB show significant bathochromic shifts with emission peaks at 534 and 541 nm, which further confirms the generation of a typical CT transition state.…”

“…In contrast, 3H2NA exhibits a strong green emission band at around 500 nm, which is assigned to the π → π* transition of an enol tautomer formed by an excitedstate intramolecular proton transfer from the hydroxyl group to the carbonyl oxygen in 3H2NA. 33 In comparison with the pristine donors, 2H1NA/TCNB and 1H2NA/TCNB show significant bathochromic shifts with emission peaks at 534 and 541 nm, which further confirms the generation of a typical CT transition state. In contrast, 3H2NA/TCNB exhibits a relatively mild bathochromic shift of 23 nm, which is consistent with the fact that the green color in fluorescence microscopy images was maintained before and after cocrystal formation in this case.…”