V P N Nampoori; Mohammed Yusuff, K K; Arun,V; Mathew, S; Robinson, P P; Jose,M(Elsevier, Journal of Dyes and Pigments, March 20, 2010)
[+]
[-]
Abstract:
The Schiff base, 3-hydroxyquinoxaline-2-carboxalidine-4-aminoantipyrine, was synthesized by the
condensation of 3-hydroxyquinoxaline-2-carboxaldehyde with 4-aminoantipyrine. HPLC, FT-IR and NMR
spectral data revealed that the compound exists predominantly in the amide tautomeric form and
exhibits both absorption and fluorescence solvatochromism, large stokes shift, two electron quasireversible
redox behaviour and good thermal stability, with a glass transition temperature of 104oC. The
third-order non-linear optical character was studied using open aperture Z-scan methodology employing
7 ns pulses at 532 nm. The third-order non-linear absorption coefficient, b, was 1.48 x 10-6 cm W-1 and
the imaginary part of the third-order non-linear optical susceptibility, Im c(3), was 3.36 x10-10 esu. The
optical limiting threshold for the compound was found to be 340 MW cm-2.
Santhi, A; Kala, U L; Nedumpara, R J; Kurian, A; Kurup, M R P; Radhakrishnan, P; Nampoori, V P N(Springer, 2004)
[+]
[-]
Abstract:
The fluorescence spectrum of the schiff base obtained from salicylaldehyde and 2-aminophenol is studied using an argon-ion laser as the excitation source and its fluorescence quantum yield (Qf) is determined using a thermal lens method. This is a nondestructive technique that gives the absolute value of Qf without the need for a fluorescence standard. The quantum-yield values are calculated for various concentrations of the solution in chloroform and also for various excitation wavelengths. The value of Qf is relatively high, and is concentration dependent. The maximum value of Qf obtained is nearly 0.78. The high value of the fluorescence quantum yield will render the schiff base useful as a fluorescent marker for biological applications. Photostability and gain studies will assess its suitability as a laser dye.