title: Synthesis, structural characterization and tautomeric properties of some novel bis-azo dyes derived from 5-arylidene-2,4-thiazolidinone.
abstract: Nine new bis-azo dyes derived from 5-arylidene-2,4-thiazolidinone have been synthesized in two steps using Knoevenagel condensation and diazotization-coupling reaction. The structures of the compounds were confirmed by UV-vis, IR, (1)H NMR and (13)C NMR spectroscopic techniques. The spectral characterizations demonstrate that there is an equilibrium between the azo (T1) and hydrazine (T2 and T3) tautomers for all prepared dyes in solutions. In addition, the solvatochromic behavior of the prepared dyes was evaluated using polarity/polarizability parameter (π(*)) in various solvents. The UV-vis absorption spectra of dyes show a bathochromic shift with increasing polarity and base strength of the solvents. Finally, the effects of acid and base on the UV-vis absorption spectra of the dyes with different substituent in diazo component are reported.
authors.affiliation: Department of Chemistry, Faculty of Sciences, University of Guilan, PO Box 41335-1914, Rasht, Iran. Electronic address: a_mohammadi@guilan.ac.ir.
authors.forename: Asadollah
authors.initials: A
authors.lastname: Mohammadi
authors.affiliation: Department of Chemistry, Faculty of Sciences, University of Guilan, PO Box 41335-1914, Rasht, Iran.
authors.forename: Mastaneh
authors.initials: M
authors.lastname: Safarnejad
mesh_terms: D001391:Azo Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D004396:Coloring Agents / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013237:Stereoisomerism; D053778:Thiazolidines / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D053778:Thiazolidines
keywords: 2,4-Thiazolidinonedione; Bis-azo dye; Solvent effect; Spectroscopy; Substituent effect; Tautomerism