113443-75-7Relevant academic research and scientific papers
New arylhydrazones of β-diketones and their optical and thermal properties
Ma, Zhen,Maharramov, Abel M.,Aliyev, Ismayil A.,Aliyeva, Irada N.,Kopylovich, Maximilian N.,Amanullayeva, Gunel I.,Mahmudov, Kamran T.,Pombeiro, Armando J.L.
, p. 16 - 20 (2012)
New arylhydrazones of β-diketones, 2-(2-(4,4-dimethyl-2,6- dioxocyclohexylidene)hydrazinyl) benzoic acid (1) and (Z)-ethyl-2-(2-(2- nitrophenyl)hydrazono)-3-oxobutanoate (2), have been synthesized by reaction of activated β-diketones with the corresponding aryldiazonium salts, and characterized by IR, 1H and 13C NMR spectroscopies and elemental analysis. In DMSO solution, 1 is stable exclusively in the hydrazone form, while 2 exists in DMSO and H2O solutions as a mixture of enol-azo and hydrazone tautomeric forms. In the latter case, an increase in the solvent polarity shifts the tautomeric balance to the enol-azo form. Solvatochromic, thermal and photoluminescent properties of 1, 2 and the known related 2-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)benzoic acid (3), (2-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)phenyl)arsonic acid (4), (Z)-2-(2-(1,3-dioxo-1-phenylbutan-2-ylidene)hydrazinyl)benzoic acid (5) and 5-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)-2,3-dihydrophthalazine-1,4-dione (6) were studied. The obtained UV-vis absorption spectra confirm that m depends on the solvent and on the nature of AHBD, but no clear correlation was found. Upon heating, 1-3, 5 and 6 are stable up to 474 K and decompose in two steps whereas 4 decomposes in three steps starting from 343 K. The kinetic parameters of the thermal decomposition were estimated suggesting a low rate of the thermal decomposition. Compounds 2 and 3 exhibit luminescence with intense emission bands with maxima at λem of 466.0 (λex = 318 nm) and 532.5 nm (λex = 315 nm), respectively, while compounds 4 and 6 show low-intensity bands at λem of 501 (λex = 396 nm) and 503 nm (λex = 389 nm). Compounds 1 and 5 display no photoluminescence.
