Exploring Coumarin-Based Boron Emissive Complexes as Temperature Thermometers in Polymer-Supported Materials

Abstract

Three coumarin-based boron complexes (L1, L2 and L3) were designed and successfully incorporated into polymeric matrixes for evaluation as temperature probes. The photophysical properties of the complexes were carried out in different solvents and in the solid state. In solution, compound L1 exhibited the highest fluorescence quantum yield, 33%, with a positive solvatochromism also being observed on the absorption and emission when the polarity of the solvent increased. Additionally in the presence of anions, L1 showed a colour change from yellow to pink, followed by a quenching in the emission intensity, which is due to deprotonation with the formation of a quinone base. Absorption and fluorescence spectra of L1 were calculated at different temperatures by the DFT/B3LYP method. The decrease in fluorescence of compound L1 with an increase in temperature seems to be due to the presence of pronounced torsional vibrations of the donor and acceptor fragments relative to the single bond with C(carbonyl)-C (styrene fragment). L1, L2 and L3, through their incorporation into the polymeric matrixes, became highly emissive by aggregation. These dye@doped polymers were evaluated as temperature sensors, showing an excellent fluorescent response and reversibility after 15 cycles of heating and cooling.

Enhancing water sensing via aggregation-induced emission (AIE) and solvatofluorochromic studies using two new dansyl derivatives containing a disulfide bound: Pollutant metal ions detection and preparation of water-soluble fluorescent polymeric particles

“…Based on our experience, in this work two dansyl derivatives (L1 and L2) were synthesized and fully characterized. Aiming the creation of new breakthroughs in the state of the art, the multiple properties and advantages abovementioned of dansyl derivatives were fully explored, such as (i) the solvatochromic effect, (ii) sensing ability towards pollutant metal ions, (iii) water detection in organic solvent via AIE, photostability, as well as (iv) the production of dansyl derivative (L1) doped polystyreneblock-polybutadiene-block-polystyrene (SBS) microparticles (L1@SBS) [37], aiming higher fluorescence quantum yields via AIE in water.…”