الملخص الإنجليزي
Seven new derivatives (14-20) of 5,7-diaryl-8-hydroxyquinoline (1) were successfully synthesized using Suzuki cross coupling reaction. The chemical structures of the seven derivatives (14-20) were confirmed from IR, 'H-NMR, 'C-NMR and mass spectrometry spectral data. The absorption and emission characteristics of the complexes of these compounds (14-20) with aluminum ion in methanol were investigated. Introducing electron withdrawing and electron donating phenyl groups at the C-5 and C-7 positions of 8-hydroxyquinoline (1) nucleus resulted in significant changes in the fluorescence spectra of the prepared aluminum complexes of these ligands. A shift of the maximum emission wavelength was observed depending on the attached phenyl group. Substitution of electron withdrawing phenyl groups at positions 5 and 7 of the quinoline ring shifted the fluorescence maximum wavelength from 2 to 39 nm towards blue (blue shift or hypsochromic shift) compared to 5,7-diphenyl-8-hydroxyquinoline (13) as in compounds 14, 17, 18, 19 and 20. On the other hand, substitution of electron donating phenyl groups at positions 5 and 7 of the quinoline ring shifted the fluorescence maximum wavelength from 1 to 25 nm towards red (red shift or bathochromic shift) compared to 5,7-diphenyl-8 hydroxyquinoline (13) as in compounds 15 and 16. In addition, 5,7-diphenyl-8 hydroxyquinoline (13) exhibited a red shift of 22 nm in the fluorescence maximum compared to the parent 8-hydroxyquinoline (1). Moreover, the fluorescence quantum yield (OE) of aluminum complexes of all 8-HQ (1) aryl-derivatives (13-20) has been increased significantly in a range of 11% to 461% relative to the parent 8-HQ (1).
