Azo Dye Derivatives Research Articles

Synthesis and biological activities of Bis alkyl 1,3,4-oxadiazole incorporated azo dye derivatives

3,5-Bis(alkyl-1,3,4-oxadiazole-2-yl azo dyes were synthesized by a multi-step reaction sequence. Structures of newly synthesized compounds were characterized and confirmed by IR, NMR, and Mass spectral studies. The synthesized compounds were screened for their antimicrobial and in vitro antioxidant properties. The results of this investigation revealed that the newly synthesized compounds are potent antibacterial and antioxidant agents. All the synthesized compounds exhibit significant biological activity and certainly hold a greater promise for discovering potent biologically active molecules.

Synthesis of Some Novel Bis 1,3,4-Oxadiazole Fused Azo Dye Derivatives as Potent Antimicrobial Agents

bis(5-(furan-2-yl)-1,3,4-oxadiazol-2-yl)azo dyes were synthesized by multistep reaction sequences, which is diazotized and coupled with different napthols and quinoline. Structure of newly synthesized compounds were characterized and confirmed by IR, NMR and Mass spectral studies. The newly synthesized azo dye fused with (5-(furan-2-yl)-1,3,4- oxadiazole) were screened for their acute toxicity and gross behavioral studies and in-vitro anti-microbial activity. Synthesized compounds exhibit significant biological activity and can certainly hold greater promise in discovering safer biologically active molecules.

Synthesis of Some Novel Bis 1,3,4-Oxadiazole Fused Azo Dye Derivatives as Potent Antimicrobial Agents

Synthesis of Some Novel Bis 1,3,4-Oxadiazole Fused Azo Dye Derivatives as Potent Antimicrobial Agents

ChemInform Abstract: Synthesis and Characterization of Novel Color Chemosensors Based on Azo Dyes for Possible Application in Opioid Pharmacology.

AbstractCoupling of morphine and 6‐acetylmorphine with aromatic diazonium salts gives novel azo dye derivatives (I) and (II) in good yields.

Spectrophotometric determination of aqueous acidity constants of three azo dyes

Abstract The two successive steps acidity constants of three azo dye derivatives D1–D3, were determined by a spectrophotometric method using 0.10 M KNO3 as supporting electrolyte in water solvent. The electronic spectra of the compounds were recorded in the course of their pH-metric titration with a standard base solution. The protolytic equilibrium constants can be solved very satisfactorily from absorbance data, by combining the data obtained in the spectrometric determinations with graphic methods as the absorbance diagrams. An A-diagram shows the relative absorbance changes at two wavelengths as a function of the pH. For a one-step system, the absorbance at any wavelength must be proportional to the absorbance at any other wavelength, so an A-diagram for all wavelength combinations for such a system must be linear (rank, s=1). However, if a system is governed by two or more equilibria, the A-diagrams corresponding to multi-step titrations will change direction every time a new equilibrium becomes dominant in the system. Analysis of the each uniform sub-region can then be used in evaluating of the corresponding equilibrium. A-diagrams for all wavelength combinations suggest that these systems have the rank two(s=2). The results revealed that the Ka(1) and Ka(2) values of different azo dyes follow the order D3>D2>D1.

Wlasciwosci pigmentow kompozytowych SiO2/barwnik i ich zastosowanie w kauczuku silikonowym

The modification of silica performed by mechanical frictioning of dyes into its surface occurring during intensive mixing has led to stable composite pigments (Table 1). Azo dye, antraquinone, perylene and indigothiazyne derivatives were used as dyeing agents. ,,Surface crayoning of silica reduces its specific surface area, particle aggregation tendency, and the formation of structures. It also lowers the filling activity towards silicon rubber thereby altering the interphase interaction resulting in an uneven dispersion of the composite pigments in the elastomer (Table 2, 3, Fig. 2, 3). Vulcanizates filled with the modified silica exhibited an increased resistance to color changes caused by weathering, however, their mechanical resistance decreased in comparison with rubber filled with unmodified silica (Table 4, 5).

Carbonic anhydrase inhibitors. Diazenylbenzenesulfonamides are potent and selective inhibitors of the tumor-associated isozymes IX and XII over the cytosolic isoforms I and II

A series of diazenylbenzenesulfonamides, azo-dye derivatives of sulfanilamide or metanilamide incorporating phenol and amine moieties, were tested for inhibition of the tumor-associated isozymes of carbonic anhydrase (CA, EC 4.2.1.1), CA IX and XII. These compounds showed moderate-low inhibitory activities against the cytosolic isoforms CA I and II (offtargets) and excellent, low nanomolar inhibitory activity against the transmembrane CA IX and XII ( K Is in the range of 3.5–63 nM against CA IX and 5.0–69.4 nM against CA XII, respectively). The selectivity ratio for inhibiting the tumor-associated CA IX over the offtarget CA II was in the range of 15–104 for these diazenylbenzenesulfonamides, making them among the most isoform-selective inhibitors targeting tumor-associated CAs (over the ubiquitous CA II). Since CA IX/XII were recently shown to be both therapeutic and diagnostic targets for hypoxic solid tumors overexpressing these proteins, such compounds held promise for the management of hypoxic tumors, which are largely non-responsible to classical chemo- and radio-therapy.

Synthesis and Spectroscopic Studies on Azo-Dye Derivatives of Polymetallic Lanthanide Complexes: Using Diazotization to Link Metal Complexes Together

Heteronuclear tetrametallic lanthanide complexes have been synthesized from stable complexes by diazotization and azo-compound formation. Luminescence spectroscopy has been used to show that the complexes used as building blocks are stable under the reaction conditions.

Potentiometric and Spectroscopic Studies of Sulfonamide Azo-Dye Complexes with some Transition Metal Ions and Uranium

Molecular structure of the azo-dye derived from sulfonamide was synthesized. The elucidation of ligand and complex structures were studied by electronic, infrared and 1H NMR spectroscopies. Proton-ligand constants of sulphonamid azo-derivatives and the stability constant of Mo (III), VO (II), UO2 (II) and Co (II) metal ions with sulfonamide azodye derivatives have been determined potentiometrically in 0.1 M KCl and 30% (v/v) ethanol-water mixture. The data are discussed in terms of the electronic character of the substituents and of the change in temperature. The pK 1-H values have been found to increase with increasing electron donating nature of the subsituents. The evaluated dissociation processes are non spontaneous, endothermic and entropically unfavourable. The order of the stability constants of the formed complexes was found to be Mo 3+ > VO 2+ > UO2 2+ > Co 2+ . The influence of substituents on the stability of the complexes was examined on the basis of an electron repelling property of the substituent. The effect of temperature on the stability of the formed complexes was studied and the corresponding thermodynamic parameters (∆G, ∆H and ∆S) were evaluated and discussed. The stoichiometries of these complexes were determined conductometrically and indicated the formation of 1:1 and 1:2 (metal:ligand) complexes.

Investigation of 3-amino-1,2,4-triazole azodye derivatives as reagents for determination of mercury(II)

AbstractThe reaction of mercury(II) with 3-(2,4-dihydroxyphen-1-ylazo)-1,2,4-triazole (HL1), 3-(2-hydroxy-5-methylphen-1-ylazo)-1,2,4-triazole (HL2), 3-(2-hydroxy-5-ethoxycarbonylphen-1-ylazo)-1,2,4-triazole (HL3), 3-(2-hydroxy-5-acetylphen-1-ylazo)-1,2,4-triazole (HL4), 3-(2-hydroxy-5-formylphen-1-ylazo)-1,2,4-triazole (HL5), and 3-(2-hydroxy-5-bromophen-1-ylazo)-1,2,4-triazole (HL6) was studied. A new, direct, and simple procedure was suggested for the spectrophotometric determination of mercury(II) based on its complexation reaction with HL1-HL6. The best reagent was found to be HL3 due to its high sensitivity and selectivity. In aqueous media of pH 9.0 containing 40 vol. % of methanol, Hg(II) reacts with HL3 to form a 1:2 (Hg(II) · HL3) complex having a sensitive absorption peak at 490 nm with the molar extinction coefficient of 3.31 × 104 L mol−1 cm−1 using 4 × 10−4 M of the reagent. Beer’s law is obeyed over the range from 0.00 µg mL−1 to 12.04 µg mL−1 of mercury(II). The proposed method was applied in the determination of mercury(II) in tap water, seawater and synthetic seawater samples, without the need of prior treatment, with satisfactory results.

Photo-induced molecular alignment of azo dye derivative

Photo-induced molecular alignment behavior of azo dye derivative (sodium 4,4′-bis (4-hydroxy-3-carboxy-phenylazo) benzidine-2,2′-disulphonate: SD1) was investigated using SD1 film prepared by spin-coating method. As-prepared SD1 film was composed of an amorphous layer with smooth surface. Upon linearly polarized UV light irradiation, the film surface was roughened slightly and X-ray diffraction measurement and transmittance electron microscope observation indicated that SD1 molecules crystallized with orientation. Molecular plane of SD1 aligned parallel to the substrate surface along the normal to the polarization direction of irradiated UV light through the trans– cis and cis– trans isomerizations of the azobenzene chromophore.

RP TLC of some newly synthesized azo-dye derivatives

The chromatographic behavior of series of azo-dye derivatives has been studied by RP C 18 TLC with water-methanol, water-acetone, water-dioxane, and water-acetonitrile mobile phases. The mechanism of retention was investigated and the retention constants, R M 0 , were determined by extrapolation. Correlations between retention constants, R M 0 , and lipophilicity, C 0 ( C 0 = R M 0 /m) and log P (ACD log P ) were investigated. Better correlations were obtained between C 0 and log P than between R M 0 and log P . These C 0 values may be use as a measure of the lipophilicity of the compounds investigated.The effect of mobile phase pH on retention of azo-dye derivatives was studied in RP C 18 TLC with diluted acetic acid-methanol, 20 + 30 ( v/v ) as mobile phase. Different methods were used to measure mobile phase pH. p K a values were determined on the basis of the relationships between analyte retention and mobile phase pH. Because the investigated azo dyes are newly synthesized compounds these p K a value...

Coupling between the Tropospheric Photochemistry of Nitrous Acid (HONO) and Nitric Acid (HNO3)

Environmental Context.Nitrous acid (HONO) is formed in the troposphere in urban, rural and remote environments via several uncertain heterogeneous and photochemical processes that involve nitric acid (HNO3). A recently recognised process is initiated by the deposition and migration of HNO3 within snow-pack surfaces to form nitrate anions (NO3−). Photo-reduction of NO3− followed by acidification of the nitrite (NO2−) photo-product leads to emissions of gas-phase HONO. Seasonal observations at Halley, Antarctica are consistent with the formation of HONO via this process, which is potentially of global significance because much of the Earth’s land (and sea) surface is covered with snow and is sunlit for much of the year. Both HONO and HNO3 significantly influence the production of ozone (O3), which acts as a greenhouse gas in the troposphere, via their respective roles as a source of hydroxyl radicals (OH•) and as a sink for OH• and nitrogen dioxide (NO2). Abstract.The tropospheric photochemistry of nitrous acid (HONO) and its coupling with that of nitric acid (HNO3) in urban, rural and remote atmospheres are highlighted in terms of established and uncertain homogeneous and heterogeneous sources and sinks, together with known and potential effects and impacts. Observations made at Halley, Antarctica, via optical detection of an azo dye derivative of HONO are consistent with snow-pack photochemical production of HONO, which has potential significance for the production of hydroxyl radicals (OH•) and ozone (O3) on regional and global scales. Recent developments in measurement methods for HONO and HNO3 are also highlighted. It is now timely to conduct a formal intercomparison of the methods in order to evaluate and enhance their capabilities, and to validate the growing body of HONO and HNO3 data obtained in urban, rural and remote locations.

Photoinduced ordering and anchoring properties of azo-dye films

We study both theoretically and experimentally the anchoring properties of photoaligning azo-dye films in contact with a nematic liquid crystal depending on the photoinduced ordering of azo-dye molecules. In the mean field approximation, we found that the bare surface anchoring energy depends linearly on the azo-dye order parameter and the azimuthal anchoring strength decays to zero in the limit of vanishing photoinduced ordering. From the absorption dichroism spectra measured in azo-dye films that are prepared from an azo-dye derivative with polymerizable terminal groups we obtain the dependence of the dichroic ratio on the irradiation dose. We also measure the polar and azimuthal anchoring strengths in nematic liquid crystal (NLC) cells aligned by the azo-dye films and derive the anchoring strengths as functions of the dichroic ratio, which is proportional to the photoinduced order parameter. Although linear fitting of the experimental data for both anchoring strengths gives reasonable results, it, predicts vanishing of the azimuthal anchoring strength at some nonzero value of the azo-dye order parameter, in contradiction with theory. By using a simple phenomenological model we show that this discrepancy can be attributed to the difference between the surface and bulk order parameters in the films. The measured polar anchoring energy is found to be an order of magnitude higher than the azimuthal strength. Our theory suggests that the quadrupole term of the spherical harmonics expansion for the azo-dye-NLC intermolecular potential might be of importance for the understanding of this difference.

Titanium dioxide mediated photocatalytic degradation of two selected azo dye derivatives, chrysoidine R and acid red 29 (chromotrope 2R), in aqueous suspensions

Photocatalytic degradation of two selected dye derivatives, chrysoidine R and acid red 29, has been investigated in aqueous suspensions of titanium dioxide under a variety of conditions. The degradation was studied by monitoring the change in substrate concentration employing UV-spectroscopic analysis and decrease in total organic carbon (TOC) content as a function of irradiation time. The degradation was studied under a variety of conditions such as reaction pH, catalyst concentration, substrate concentration, different types of TiO 2 and in the presence of electron acceptors such as hydrogen peroxide (H 2O 2) and ammonium persulphate (NH 4) 2S 2O 8 besides molecular oxygen. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst Degussa P25 was found to be more efficient as compared with other photocatalysts. The degradation products were analysed by GC/MS analysis technique, and probable pathways for the formation of different products have been proposed.

Toxicological effect of indole and its azo dye derivatives on some microorganisms under aerobic conditions

Azo dyes are ubiquitous commercial chemicals that present unique environmental problems. The azo dyes in particular can undergo natural anaerobic degradation to potentially carcinogenic amines. They pose a major problem for water-treatment plants downstream. One strategy to remidate polluted surface contaminants is to make use of the degradative capacity of bacteria rather than using destructive chemical reactions. Therefore, pathogenic and non-pathogenic microorganisms namely; Bacillus thuringiensis, Bacillus subtilis, Bacillus megaterium, Proteus vulgaris, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Saccharomyces cerevisiae have been chosen and the toxicological effect of indole and its azo dye methyl derivatives on these microorganisms was studied under aerobic conditions. While these compounds have showed remarkable activity against B. megaterium, B. subtilis, B. thuringiensis and S. aureus, they did not exhibit any activity against P. vulgaris. However, indole acted as an inhibitor on all of these compounds specially the Gram negative bacterium P. aeruginosa.

Semiconductor-mediated photocatalysed degradation of two selected azo dye derivatives, amaranth and bismarck brown in aqueous suspension

Semiconductor-mediated photocatalysed degradation of two selected azo dye derivatives such as amaranth ( 1) and bismarck brown ( 2) has been investigated in aqueous suspension by monitoring the change in substrate concentration employing UV spectroscopic analysis technique as a function of irradiation time. The degradation was studied under different conditions such as types of TiO 2, pH, substrate concentration, catalyst concentration, and in the presence of electron acceptors such as hydrogen peroxide (H 2O 2), potassium bromate (KBrO 3) and ammonium persulphate (NH 4) 2S 2O 8 besides air. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst Degussa P25 showed comparatively highest photocatalytic activity. The dye derivative, bismarck brown ( 2) was found to degrade faster than amaranth dye ( 1).

Semiconductor-mediated photocatalytic degradation of anazo dye, chrysoidine Y in aqueous suspensions

The photocatalytic degradation of an azo dye derivative, chrysoidine Y (1), was investigated in aqueous suspensions of titanium dioxide and zinc oxide by monitoring the change in substrate concentration employing UV spectroscopic analysis and decrease in total organic carbon content as a function of irradiation time under a variety of conditions. The degradation of the dye was studied under different conditions such as pH, catalyst concentration, substrate concentration and in the presence of electron acceptors such as hydrogen peroxide (H 2O 2) and potassium bromate (KBrO 3) besides molecular oxygen. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst Degussa P25 was found to be more efficient as compared with zinc oxide

Anchoring properties of photoaligned azo-dye materials.

The photoinduced alignment of a liquid crystal (LC) on films of azo dyes was studied for the liquid crystal display applications. In order to improve the alignment stability of the photoaligned dye (SD-1), the azo-dye derivative with polymerizable terminal groups was synthesized (SDA-1). The films of SDA-1 exhibit good photoalignment properties and ultraviolet stability after thermal polymerization. We investigated the anchoring coefficient for polar and azimuthal energy for both azo-dyes SD-1 and SDA-1 using a differential method developed by us. The polar and azimuthal anchoring strengths of azo-dye aligning materials are comparable with those of usual polyimide aligning materials. The electro-optic response of a 90 degrees twisted LC cell remains almost the same after heating up to 200 degrees C, i.e., the anchoring energy remains considerably high.

P‐104: Aligning Layers Using Azo Dye Derivatives for Liquid Crystal Devices

AbstractThe photo‐induced alignment of an azo dye film and liquid crystal (LC) alignment on it are discussed for the liquid crystal display applications. Considerable dichroism is induced in the azo dye SD1 film not only by polarized UV light but also by obliquely incident non‐polarized UV light irradiation. It was found that sulfo groups in the azo dye molecule play an important role in the LC alignment on the film. Large pretilt of LC on the photo‐aligned film was achieved simultaneously, because the azo dye molecules can be easily reoriented out of the film plane by obliquely incident non‐polarized light irradiation. In order to improve stability of the photo‐aligned film, a monomer derived from the azo dye was synthesized. After thermal polymerization, the film of it also exhibit good photo‐alignment properties. Improvement of durability against light exposure and moisture was observed in the LC cell using it.