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

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. (C) 2016 Published by Elsevier B.V.