Preparation, Characterization and Analytical Studies of novel Azo dyes and Diazo dyes

The amino {4-hydroxy-3-[(E)-{4-[(5-methylisoxazol-3-yl) sulfamoyl] phenyl} diazenyl] phenyl} acetic acid (1) and the amino {4-hydroxy-3,5-bis[(E)-{4-[(5-methylisoxazol-3-yl) sulfamoyl] phenyl} diazenyl] phenyl} acetic acid (2) were Prepared. The resulting azo and diazo dyes were then characterized using m.p., IR, UV-visible, mass spectrum and 1H-NMR spectrum. Analytical studies were carried on the azo dye (1) and the diazo dye (2). The best solubility of (1) and (2) was in methanol and ethyl acetate respectively, with no deviation from the linear relationship in each dye, which is due to the fact that the effect of the dielectric constant is the main factor that can control the shift of the absorption beaks. Though, the pH effects of (1) and (2) in a range of buffer solution were showed one and two isopiestic points respectively. Calculation of the ionization (pKa) and the protonation (pKp) constants by using the half height method was associated to the nitrogen atom and the OH-groups respectively. The pKp1, pKa1 and pKa2 were also intended. But, the value of the pKp2 was absent in the azo dye (1) and seems to be equal to 2.5 in the diazo dye (2). These results were indicated the suggested ionization scheme in acidic and basic medium of each dye. Furthermore, the dyes with different concentrations have harmless, nontoxic and no haemolysis effects.

Molecular Docking Study of Some Nitro Diazo Dye Derivatives as Antiviral Candidates of COVID-19

In this study, the computerized molecular docking method was used to investigate the interactions of five nitro diazo dye derivatives 1-5 with COVID-19, CLpro, RAF and PLpro as very important viral proteins to target the coronavirus SARS-CoV-2. Among the used diazo dyes, compound 5 showed the highest binding free energies and the lowest inhibition constants Ki with all studied proteins, and it exhibits a large effect to inhibit the activities of the RAF and COVID-19. Therefore, compound 5 may be useful as an antiviral candidate that worth more trials for COVID-19 disease. The binding sites of compound 5 with the tested viral proteins were evaluated.

Microwave-assisted synthesis of disazothiazolone dyes as antibacterial agents and their application in polyester printing

Purpose This study aims to represent a successful simple method for the synthesis of some novel dyes based on thiazole derivatives and their applications in textile printing. Design/methodology/approach 2-(benzo[d]thiazol-2-ylmethyl)thiazol-4(5H)-one compound is prepared by convention heating and microwave technique then used as a coupling agent, which reacts with different diazonium Salt to form diazo dyes. Findings The synthesized diazo dyes are confirmed via spectral data (IR,1H-NMR, 13C-NMR and Mass spectra). The dyes are used to print polyester fabric. The obtained results clarified that the prints have good color strength, brilliant color and highly durable antibacterial activity. Originality/value The authors designed efficient synthesis for some novel thiazolone dyes. The novel procedure features short-reaction time, very good yields and a simple workup. The authors studied the antibacterial activity and their application in printing polyester fabrics.

Angle-Sensitive Photonic Crystals for Simultaneous Detection and Photocatalytic Degradation of Hazardous Diazo Compounds

Congo Red (CR) and Amido Black 10B (AB-10B) are anionic diazo dyes, which are metabolized to produce a bioaccumulative and persistent carcinogen, benzidine. In this regard, an angle sensitive sensor composed of photonic crystal supported photocatalyst was fabricated for the simultaneous detection and photocatalytic degradation of diazo dyes from aqueous solutions. Reflectance spectroscopy was used in the detection of CR and AB-10B, which was based on the emergence of the incident angle dependent reflection peaks from the TiO2 coated two-dimensional photonic crystal (2D-PhC) surfaces and their subsequent quenching due to the presence of dye molecules whose absorbance peak intensity overlapped the reflection peak intensity of TiO2 at the respective angle. Interestingly, ultraviolet (UV) mediated photocatalytic degradation of CR and AB-10B was achieved using the same TiO2 coated 2D-PhC surfaces. 2D-PhC underneath the TiO2 layer was able to confine and localize the light on the TiO2 coated 2D-PhC surface, which enhanced the light absorption by dye molecules on the TiO2 surface and the photocatalytic efficiency in the degradation of CR and AB-10B. Finally, this proof-of-concept study demonstrated the fabrication of copolymer film based photonic crystal supported photocatalytic device, which can be used for developing miniaturized sensors competent in on-field detection and degradation of pollutants.

Biophysical Study for the Interactions of Some Diazo Dyes with Human Serum Albumin

The biophysical interactions between the human serum albumin HSA and three synthesized diazo dyes 1-3 have been investigated by thermodynamic parameters and molecular docking technique. The binding constants Kb were calculated and the compounds were ranked according to their docking free energy. Different interactions were elucidated at the active site of the protein. Among these interactions is the hydrogen bonding which plays an essential role in the interaction with the protein. Both the theoretical and practical studies have agreed that diazo dye 1 has the strongest interaction with the active site.