Synthesis, electronic spectra, and solvatochromic behaviour of 4-arylidene-1-(2,4-dinitrophenyl)-3-methyl-2-pyrazolin-5-ones

SAID A. IBRAHIM and M. S. K. YOUSSEF. Can. J. Chem. 62, 2841 (1984). The uv-visible electronic spectra of 4-arylidene-l-(2.4-dinitrophenyl)-3-methyl-2-pyrazolin-5-ones have been studied. The different bands observed have been assigned to the proper electronic transition. Solvatochromic behaviour of these compounds is investigated by studying their visible spectra in organic solvents of different polarities. The longer wavelength band displayed by para-hydroxy derivative is assigned to an intermolecular CT transition. The solvated H-bond complexes formed between ethanol or DMF and the para-hydroxy derivative are investigated. Transition moment (kTL). A G , and Kr values of these complexes have been determined.