Modulation of Dye Fluorescence by Photoinduced Intramolecular Charge Transfer with Resonance-Assisted Hydrogen Bond
Fluorescent dyes with photoinduced intramolecular charge-transfer (ICT) process driven by β-enaminone group capable to form resonance-assisted hydrogen bond (RAHB) structure were prepared from aromatic and heterocyclic precursor molecules, such as 1-aminopyrene, 9-amino acridine, and adenine. The electronic ground and excited-state spectral properties of these new dyes are modulated by the type of substituent in the β-enaminone group and solvent interaction as well. The excited-state properties and the complex kinetics observed are results of the interplay between charge and proton transfer, together with the presence of possible conformers or tautomers associated with the keto-amine/enol-imine equilibrium. The applications of such dye derivatives as molecular probes in radical copolymerization with acrylic monomers and as reporters in silver nanoparticles dye interaction in solution are also discussed.
KeywordsSilver Nanoparticles Locally Excited Pyrene Derivative Purine Ring Biexponential Decay
The authors thank Brazilian Science Foundation FAPESP and CNPq for financial support. ERS and CAS are graduate fellows of CAPES. RVP thanks FAPESP for postdoctoral fellowship.
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