Efficient synthesis, fluorescence and DFT studies of different substituted 2-chloroquinoline-4-amines and benzo[g][1,8]naphthyridine derivatives

Abstract

Abstract An efficient and single step strategy for synthesizing new functionalized benzo[b][1,8]naphthyridine derivatives is presented. Benzo[g][1,8]naphthyridines have been synthesized by the condensation of substituted 2-chloroquinoline-3-carbaldehydes with various 2-chloroquinoline-4-amines, 1H-Indazole-6-amine in basic medium. The electro luminescence and photophysical properties of a series of benzo[g][1,8]naphthyridines 5(a–d), 6(a–d) and 2-chloroquinoline-4-amines 3(a–f) are reported and investigated with the aim of arriving at good fluorescent materials. Moreover, the effect of electron donor-acceptor substituent on fluorescence properties of all molecules has been investigated along with their fluorescent quantum yields. Furthermore we analyzed for band gap energy associated with HOMO-LUMO, through density functional (DFT M06-HF) studies. The experimental observations are in close agreement with the theoretical calculation. All the synthesized compounds were identified on the basis of their NMR, Mass spectral data analyses.