Synthesis of quinolone substituted pyrazoles, isoxazoles and pyridines as a potential blue luminophors.

Series of quinolone C(3)-substituted pyrazolines, isoxazolines, pyridines and pyrimidines were synthesized in good yields by the cyclocondensation reactions of 1, 2-unsaturated ketones and hydrazines, hydroxylamine hydrochloride and dimedone respectively. The quinolone derivatives (3, 5 and 7) were synthesized and further studied for their photophysical properties. High absorption and quantum yield are found for N(1)-phenyl and C(3,4)-dimethoxy substituents on phenyl ring (3h). Energy optimization by PM6 methods showed high stability required for selection of suitable candidates to be use as future blue emitters.

Synthesis and fluorescence properties of donor-acceptor-substituted novel dipyrazolo[3,4-b:3',4'-d]pyridines (DPP).

A rapid and efficient method for the synthesis of novel dipyrazolo[3,4-b:3',4'-d]pyridines (DPP) from pyrazolo[3,4-b]pyridine was successfully developed. The DPP derivative was further N-alkylated (6, 8) as well as N-linked with amino acids (13) and their photophysical properties were studied along with N-aryl DPP 4 and observed that the chromophores at C(4) position in the aryl ring changed the absorption and emission lambda(max).

Synthesis of novel spiro-oxazino-quinoline derivatives and study of their photophysical properties.

A convenient route was successfully developed for the synthesis of novel heterocycles such as spiro-oxazino-quinoline derivatives from 2-aminoquinoline-3-carbonitrile (4) in good yield. The Spiro-quinoline derivatives (6, 8 and 10) were synthesized and further studied for their photophysical properties. Semiempirical molecular orbital calculation (PM3/PM6 for structure) proves to be a suitable tool for the prediction of absorption and fluorescence properties of these compounds.

Fluorescence properties of donor acceptor chromophores on newly synthesized pyridine-3-carbonitriles.

A convenient route was successfully developed for the synthesis of novel heterocycles such as pyridine-3-carbonitriles 4 from chalcone 3 in good yields. The pyridine-3-carbonitrile derivatives synthesized were further studied for their photophysical properties and observed that absorption and emission was changed, due to the chromospheres at C4-position in phenyl ring and C2-position in pyridine-3-carbonitrile derivatives.