Spectra and halochromism of quinoline nucleus-containing chalcone analogs

Abstract

The electron absorption spectra of 14 quinoline analogs of chalcone are measured in concentrated sulfuric acid. It is shown that not all the compounds studied in that solvent exhibit halochromism because protonation of the quinoline ring system greatly decreases ketone basicity. It is established that replacement of phenyl in the quinoline chalcone molecules by furyl-2, thienyl-2, and 4-chlorophenyl causes a bathochromic shift. Similar replacement of phenyl by 5-nitrofuryl-2, 5-nitrothienyl-2, and 4-nitrophenyl gives rise to a hypsochromic shift, and there is no halochromic coloration.