Tautomery and acid-base properties of some azoderivatives of benzoylacetone |
| |
Authors: | Kamran T Mahmudov Ravan A RahimovMahammad B Babanly Parvin Q HasanovFaig G Pashaev Arzuman G GasanovMaximilian N Kopylovich Armando JL Pombeiro |
| |
Institution: | a Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, TU Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugalb Department of Chemistry, Baku State University, Z. Xalilov Str. 23, Az 1148 Baku, Azerbaijanc Institute of Petrochemical Processes, National Academy of Sciences of Azerbaijan, Hojaly Ave. 30, 1025 Baku, Azerbaijan |
| |
Abstract: | The structural, tautomeric and acid-base properties of the new 1-phenyl-2-(2-hydroxy-3-sulfo-5-chlorophenylhydrazo)butane-1,3-dione (H2L1), 1-phenyl-2-(2-hydroxy-3,5-disulfophenylhydrazo)butane-1,3-dione (H2L2), 1-phenyl-2-(2-hydroxy-3-sulfo-5-nitrophenylhydrazo)butane-1,3-dione (H2L3) and 1-phenyl-2-(2-hydroxy-4-nitrophenylhydrazo)butane-1,3-dione (H2L4) were studied using IR, 1H and 13C NMR spectroscopies and potentiometry. The study reveals that H2L1-4 and the known 1-phenyl-2-(2-hydroxyphenylhydrazo)butane-1,3-dione (H2L5) exist in solution as a mixture of Z-enol-azo-II and hydrazo-III tautomeric forms and that an increase in the solvent polarity shifts the tautomeric balance to the enol-azo form. The thermodynamic parameters of the proton dissociation in H2L1-5 were determined showing that this process is unspontaneous, endothermic and entropically unfavorable. |
| |
Keywords: | Azoderivatives of benzoylacetone Tautomery Thermodynamic parameters |
本文献已被 ScienceDirect 等数据库收录! |
|