Banca de DEFESA: LEDJA BRITTES DE OLIVEIRA DAVI DE VASCONCELOS

SYNTHESIS OF DANSYL DERIVATIVES AS CARBON DOTS PRECURSORS: APPLICATIONS SUCH AS pH SENSORS AND WHITE LIGHT EMITTING DIODES

Dansylated Derivatives; Dansyl Chloride; Carbon Dots; Nanothermometry; WLEDs; Lervicidal Agents.

Dansyl derivatives present double fluorescence with only one excitation, due to the phenomenon of TICT
present in these molecules, as they present in their structure an electron donor group (dimethylamino group)
and an electron acceptor group (naphthalene sulfonyl group). These compounds have been successfully used
in distinct and timely applications such as real-time microviscosity probes, molecular recognition, as well as
live cell imaging. And because they have different atoms in their structures, such as S, N, O and Cl, they also
have potential for application in the synthesis of carbon dots (C-dots). Therefore, the derivatives o, m and pphenyldiamine dansylated, o-aminothiophenyldansylated and hydroquinonadansylated were synthesized in
excellent yields from a nucleophilic acyl substitution reaction between dansyl chloride o, m and pphenyldiamine, o-aminothiophenol and the hydroquinone. After characterization by 1H NMR, 13C NMR and
FTIR the derivatives and their precursors were applied for the synthesis of C-dots in hydrothermal reaction
by the bottom-up route. The C-dots obtained exhibited functional groups characteristic of the precursor
materials, with N and S doping, diameters smaller than 6 nm, emission dependent and independent of the
excitation wavelength. The C-dots obtained from p-phenyldiaminedansyl, dansyl chloride and pphenyldiamine were used to assemble white LEDs using the RGB system with PVP films that exhibited CRI
of up to 89 and CIE coordinates of (0.33, 0.31) and (0.28, 0.33) under UV excitation at 370 and 390 nm,
respectively. The C-dots of dansyl chloride were evaluated in nanothermometry and showed potential for
applications as ratiometric nanothermometers and fluorescent and colorimetric pH sensors.