Five different types of 2D-π-A pyran-based dyes, (vinylcyanoacetate)pyran derivatives, having two donor (2D) and one acceptor (A) groups, were synthesized. All compounds showed significantly large Stokes shift. The π-conjugated moiety, such as carbazolyl group, as an electron donor group, was not su...
Five different types of 2D-π-A pyran-based dyes, (vinylcyanoacetate)pyran derivatives, having two donor (2D) and one acceptor (A) groups, were synthesized. All compounds showed significantly large Stokes shift. The π-conjugated moiety, such as carbazolyl group, as an electron donor group, was not suitable to efficient red-emission color saturation. A locked ring structure of electron donor group led to narrow the full width at half maximum (fwhm) and to increase the dipole moment at ground state. Bulky donor groups also led molecular stability to restrain the electronic perturbation at excited state. A new pyran-based CTD monomer, allyl-2-(2,6-bis((E)-4- (dimethylamino)styryl)-4H-pyran-4-ylidene)-2-cyanoacetate(6) was success fully synthesized by Knoevenagel reaction. Copolymerization of 6 with styrene (St), methyl methacrylate (MMA), and acrylonitrile (AN) afforded copolymers with different polarity, P(St-co-6), P(MMA-co-6), and P(AN-co-6), respectively. IR and UV-vis absorption spectra revealed that 6 is incorporated into the copolymers. The 6 in the copolymers exhibited absorption and fluorescence properties which are completely different from 2. All these copolymers showed significant blue-shifts in emission relative to 6. Also, their lmax, abs and lmax, em increased with an increase in dielectric constant (ε) of the polymer matrix in order PAN (ε = 5.5) > PMMA(3.3) > PSt(2.5). The copolymers in DMF showed blue-shifts in emission along with aggregation by addition of methanol while copolymers in 1,4-dioxane showed a red-shift. The fluorescence intensity of P(St-co-6) and P(MMA-co-6) decreased by aggregation while that of P(AN-co-6) increased. Also. We synthesized three different types of charge transfer dye-based copolymer gels. These polymer gels showed different swelling ratios in various solvents with different polarity. Also, the polymer gels exhibited different FL responses upon exposure to the organic solvents. Functional equations between Δλ_(max), FL of the polymer gels and dielectric constant of solvent chemicals were useful to estimate the polarity of unknown analytes. The chemoselective responses of the polymer gels permitted the visual identification of a wide range of organic solvents.
Five different types of 2D-π-A pyran-based dyes, (vinylcyanoacetate)pyran derivatives, having two donor (2D) and one acceptor (A) groups, were synthesized. All compounds showed significantly large Stokes shift. The π-conjugated moiety, such as carbazolyl group, as an electron donor group, was not suitable to efficient red-emission color saturation. A locked ring structure of electron donor group led to narrow the full width at half maximum (fwhm) and to increase the dipole moment at ground state. Bulky donor groups also led molecular stability to restrain the electronic perturbation at excited state. A new pyran-based CTD monomer, allyl-2-(2,6-bis((E)-4- (dimethylamino)styryl)-4H-pyran-4-ylidene)-2-cyanoacetate(6) was success fully synthesized by Knoevenagel reaction. Copolymerization of 6 with styrene (St), methyl methacrylate (MMA), and acrylonitrile (AN) afforded copolymers with different polarity, P(St-co-6), P(MMA-co-6), and P(AN-co-6), respectively. IR and UV-vis absorption spectra revealed that 6 is incorporated into the copolymers. The 6 in the copolymers exhibited absorption and fluorescence properties which are completely different from 2. All these copolymers showed significant blue-shifts in emission relative to 6. Also, their lmax, abs and lmax, em increased with an increase in dielectric constant (ε) of the polymer matrix in order PAN (ε = 5.5) > PMMA(3.3) > PSt(2.5). The copolymers in DMF showed blue-shifts in emission along with aggregation by addition of methanol while copolymers in 1,4-dioxane showed a red-shift. The fluorescence intensity of P(St-co-6) and P(MMA-co-6) decreased by aggregation while that of P(AN-co-6) increased. Also. We synthesized three different types of charge transfer dye-based copolymer gels. These polymer gels showed different swelling ratios in various solvents with different polarity. Also, the polymer gels exhibited different FL responses upon exposure to the organic solvents. Functional equations between Δλ_(max), FL of the polymer gels and dielectric constant of solvent chemicals were useful to estimate the polarity of unknown analytes. The chemoselective responses of the polymer gels permitted the visual identification of a wide range of organic solvents.
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#전하이동형 색소 공중합체 aggregation(회합) VOC 센서
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