Thiazolylazo Dye Research Articles

The syntheses, photophysical properties and pH-sensitive studies of heterocyclic azo dyes bearing coumarin-thiophene-thiazole.

This study reports the synthesis of two novel thiazolylazo dyes (4 and 5) bearing coumarin-thiophene moiety. UV-Vis spectroscopy was used to investigate the photophysical properties of 4 and 5 in different solvents. The dyes displayed good potential for hydroxide sensing in different mediums. The reversibility was also studied, and it was found that 4 and 5 could be reverted to their original state by adding acid. Furthermore,the acidochromic properties were studied in protic and aprotic media. Both dyes displayed a good acidochromic response in DCM. Moreover, 4 and 5 were investigated for pH sensing, and it was found that both compounds displayed changes in absorption spectra in a basic media. The theoretical calculations were carried out to investigate the deprotonation and protonation mechanisms using density functional theory (DFT). The thermal properties of the dyes were investigated using thermogravimetric analysis (TGA). The results showed good thermal stability up to around 200°C.

Synthesis, characterization, and multifunctional applications of novel metal complexes based on thiazolylazo dye

AbstractHerein, a novel ligand, namely, N,N‐dimethyl‐4‐((4‐(pyridin‐2‐yl)thiazol‐2‐yl)diazenyl)aniline, and its solid Mn (II), Co (II), Ni (II), and Cu (II) complexes have been synthesized and characterized. The photophysical properties of the thiazolyl azo ligand, L, have been investigated in various solvents of different polarities. The absorption and fluorescence maxima of the ligand show a strong dependence on the solvent polarity. The metal ions sensing response to Mn (II), Co (II), Ni (II), and Cu (II) ions were also investigated in ethanolic solutions. The novel solid complexes of hexacoordinate Mn (II), Co (II), Ni (II), and Cu (II) of the ligand have the molar ratio 2:1 (M:L) and general chemical formula [M2(L)(H2O)4Cl4]·nH2O. The presence of metal–metal interaction was proved by the low magnetic moment values μeff of metal complexes. The UV–Vis spectra of the ligand and its metal complexes displayed bands characteristic to different types of transitions inside the molecules. The metal complexes show additional absorption bands of very low intensity around 650–690 nm attributed to d–d transitions within the metal ion indicating octahedral geometry. The geometry of the ligand and its complexes was also theoretically confirmed using the DMOL3 program and density functional theory (DFT). The free ligand and its metal complexes have been studied for their DNA‐binding properties using steady‐state absorption and emission techniques. They demonstrated successful binding properties against CT‐DNA in an intercalative mode. Additionally, the ligand and its metal complexes have also been successfully applied to polyester fabrics as disperse dyes. Multifunctional properties such as color representation, colorimetric data (L*, a*, b*, C*, h*, K/S), and fastness properties of the dyed samples have been discussed and evaluated in detail. These dyes have proven their efficiency in dyeing polyester fabrics, as they give satisfactory results in fastness properties, colorimetric data. Moreover, the antioxidant and antitumor activities for the synthesized compounds were evaluated.

Preparation, spectroscopic and anticancer studies of metal antibiotic Chelation Ni(II), Cu(II) and Zn(II) 4,5-dimethyl Thiazolylazo complexes

This work included synthesis of new ligand 2-[2-(4,5-Dimethyl thiazolyl)azo]-4,6-dimethyl phenol (DMeTADMeP) by coupling of diazonium salt of 2-amino-4,5-dimethyl thiazole with (2,4-dimethylphenol). Also, preparation of new series of chelate complexes of Ni(II), Cu(II) and Zn(II) metal ions were also prepared by mixing solution of metal salts with solution of ligand at mole ratio[ M:L] [1:2] for Ni(II), Cu(II) and Zn(II) metal ions. The structures of the azo dye ligand and its metal complexes were confirmed by various analytical techniques like by UV-visible, FT-IR, Mass spectroscopic, 1H-NMR, 13C-NMR, (C.H.N.S) element analyses, molar conductance, FESEM and XRD diffraction studies. The antibacterial and antifungal activity of thiazolyl azo dye and its metal complexes were shown activity towards both bacterial Escherichia coli (gram negative), streptococcus (gram positive) and Penicillium as antifungal. The results shows that this kind of compounds plays an important role in the rate of inhibition of the growth of bacterial. The anticancer activity was also conducted of the (DMeTADMeP) and Cu(II)-complex by cells cytotoxicity and screen for in vitro antitumor activity against human Hepatocellular cancer. The results indicated that this type of this compounds play an important role in the rate of inhibition of the growth cells of cancerous, undoubtedly the possibility of using them as anti-cancer drugs in the field of medicine and pharmacy.

Synthesis, Spectral Properties And Anticancer Studies of Novel Hetrocyclic Azo Dye Ligand Derived From 2-Amino-5-methyl thiazole with Some Transition Metal Complexes

This research included preparation of the thiazolyl azo ligand 2-[2-- (5-Methyl thiazolyl)azo]-4-Ethoxy phenol (MeTAEP) and their metal complexes which was prepared by coupling of diazonium salt produced from diazonited 2-amino-5-methyl thiazole and 4-Ethoxy phenol, New series of chelate complexes of Cu(II), Ag(I) and Au(III) metal ions were also prepared by mixing solution of metal salts with solution of ligand at mole ratio[ M:L] [1:2] for Cu(II) and [1:1] for Ag(I) and Au(III) metal ions. The synthesized compounds were confirmed by elemental analysis, molar conductance measurments, magnetic susceptibility, Mass spectrum, 1H- NMR,13C- NMR, FTIR, UV-Visb., (TGA), FESEM and X-ray diffraction studies. The biological activity of thiazolyl azo dye ligand and its complexes were tested against the sensitive organisms Escherichia coli (gram negative), streptococcus (gram positive) as antibacterial and Aspergillus Niger and Penicillium. sp as antifungal, The anticancer activity of the(MeTAEP), Ag(I) and Au(III) complexes were screened for in vitro; antitumor activity against human breast cancer.

Synthesis of novel biologically active thiazole dyes and their applications

PurposeThis study aims to focus on the possibility of developing new thiazole azo dyes with good colouristic application properties, biological and pharmacological activities.Design/methodology/approachCoupling of curcumin with different aromatic diazonium salts of 2-amino thiazole derivatives, such as 2-aminobenzothiazole, 2-amino-5-phenylthiazole, 2-amino-5-methylthiazole and 2-amino-5-nitrothiazole-produced novel azo dyes. Structures of all synthesised dyes were fully confirmed via spectroscopic and analytical methods. Those compounds were examined for their antimicrobial, anticancer and antioxidant activities. They were applied on polyester fabrics and, subsequently, their dyeing properties, light, washing, perspiration, rubbing and sublimation fastness were determined.FindingsPrepared dyestuffs were suitable for dyeing polyester fabrics. It was found that all prepared dyes possess high colour strength, as well as good overall fastness properties. Meanwhile, the synthesised compounds exhibited good biological and pharmacology activity.Research limitations/implicationsSynthesis of these four azo dyes for textile dyeing was not conveyed earlier.Practical implicationsThaizolyl disperse dyes were responsible for giving better colour assessment and fastness properties on polyester fabrics.Social implicationsAlthough, most of synthesis eco-friendly dyes are expensive, they are showing a good antimicrobial and anticancer activity.Originality/valueIt gave straightforward approach to synthesise novel thiazolyl azo dyes with good biological, pharmacology activities, good colour assessment, and fastness properties.

Colorimetric detection of histidine in aqueous solution by Ni2+ complex of a thiazolylazo dye based on indicator displacement mechanism

A colorimetric naked-eye chemosensor for histidine (His) was established by mixing a thiazolylazo dye and Ni2+ in a 1:1 M ratio (TAMSMB-Ni2+). Due to the interaction of Ni2+ with His, TAMSMB was regenerated upon the addition of His to TAMSMB-Ni2+ to lead a significant hypsochromic shift in absorption spectra accompanied by a visual color change from red to yellow which can be directly observed by the naked eye. On the other hands, other amino acids did not trigger any significant changes in absorption properties and solution color. Moreover, it exhibited the selective recognition of His without obvious interference from other amino acids. Thus, TAMSMB-Ni2+ can act as a simple and efficient colorimetric chemosensor for His with sensitivity and selectivity in aqueous solution.

Identification of tautomeric intermediates of a novel thiazolylazonaphthol dye – A density functional theory study

The recently synthesized thiazolylazo dye, 1-[5-benzyl-1,3-thiazol-2-yl)diazenyl]naphthalene-2-ol called shortly BnTAN, is studied by density functional theory (DFT) in three tautomeric forms in order to explain the available 1H NMR, UV–Vis and FTIR spectra. An experimentally observed IR band at 1678 cm−1, assigned to the CO bond stretching vibration, supports the notion that BnTAN retains in the less stable keto-form even in the solid state due to an ultrafast single-coordinate intramolecular proton transfer. This finding is also in a good agreement with an X-ray crystallography analysis which indicates an intermediate position of the proton between the –OH and –N=N– groups. Calculations also show that some experimentally observed 1H NMR signals could be considered as being averaged values between theoretically calculated chemical shifts for the corresponding protons in the keto- and enol-tautomers. At the same time the UV–Vis spectra are almost insensitive to the tautomerization processes as the main single band absorption at 500 nm is present in all tautomers according to our TD DFT simulations. The minor differences in spectral features of the long-wavelength visible region are also noted and discussed with respect to the manifestation of the less stable tautomer form.

A simple non-extractive green method for the spectrophotometric sequential injection determination of copper(ii) with novel thiazolylazo dyes.

This work introduces two new thiazolylazo dyes 1-[(5-benzyl-1,3-thiazol-2-yl)diazenyl]naphthalene-2-ol (BnTAN) and 1-[5-(4-sulfonamidobenzyl-4-methyl-1,3-thiazol-2-yl)diazenyl]naphthalen-2-ol (SABnMeTAN) as possible reagents for spectrophotometric determination of copper(ii) in water samples in the form of a chelate complex. The substances were synthesized for the first time and characterized using the NMR technique. The main characteristics of ligands, such as molar absorption coefficients and protonation constants, were evaluated spectrophotometrically. A non-extractive sequential injection spectrophotometric method for the determination of copper(ii) in the presence of Triton X-100 was developed. The linear range of the calibration plot was observed from 0.063 to 1.270 mg L−1 and the detection limit was 0.044 mg L−1. The SIA method was compared with the respective manual method and applied for the determination of copper(ii) in tap and river water.

Synthesis of some transition metal complexes with new heterocyclic thiazolyl azo dye and their uses as sensitizers in photo reactions

A new heterocyclic thiazolylazo dye ligand, 2- [¯2-(4, 5- dimethyl thiazolyl) azo ] -4-Ethoxy Phenol (DMeTAEP), (LH) was synthesized by the diazotization of 4.5-dimethyl thiazolylazonium chloride and coupling with 4- Ethoxy phenol in alkaline alcoholic solution under suitable optimized experimental conditions to yield a new azo dye ligand. The structure of ligand and its complexes was prepared from Co(III), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Ag (I) and Au(III) ions. They confirmed by XRD, SEM, (TG-DTG) thermal analysis, 1H-NMR,UV–visb, mass and FT-IR spectroscopic methods, elemental analysis, atomic absorption, magnetic susceptibility and molar conductance. The mole ratio [M: L], it was also studied which was 1:1 for Ag (I) and Au (III) complexes and 1:2 The rest of the metal complexes. The isolated solid complexes are found to have the general formula [M (L)2 ] Cln.mH2O, where n = 1, m = 0 when M = Co (III) and n = 0, m = 1 when M = Ni (II), and Hg(II) while n = 0 and m = 0 when M = Cu (II), Zn (II), Cd (II) and ]ML (H2O)] of Ag(I) – complex but Au(III)-complex structural formula was [Au(L)Cl] Cl conductivity measurements for prepared complexes showed 1:1 electrolyte for Co(III(and Au(III) complexes and non – electrolyte the rest of complexes. The spectral and analytical data revealed that this ligand behaves as a tridentate chelating agent and coordination number of all metal ions were found to be six except for Ag (I) and Au (III) which was four. The activities of complexes were examined as sensitizers in the photocatalytic reaction of p-nitro aniline (PNA) which is used as a model of water pollutants.

Zn(II) and Cd(II)-azido/thiocyanato complexes with thiazolylazo dye and triphenylphosphine: synthesis, characterization and fluorescence

[M(L)(PPh3)2X2] [where M = Zn(II) or Cd(II); L = 4-(4′-phenyl, 2′-thiazolylazo)chlorobenzene (L1 ), 4-(4′-phenyl, 2′-thiazolylazo)bromobenzene (L2 ), 4-(4′-phenyl, 2′-thiazolylazo)iodobenzene (L3 ); PPh3 = triphenylphosphine; X = or NCS−] have been prepared. The complexes were characterized by microanalyses, molar conductance, IR, UV–vis, 1H NMR, 31P NMR, and mass spectral studies. IR spectra reveal that L1–3 coordinate bidentate via azo and thiazole nitrogens. An octahedral geometry is proposed for all the complexes. Thermal behavior indicates that the thiocyanate complexes are more stable than the azide complexes. All the complexes exhibit blue-green emission as a result of fluorescence from the intraligand (π → π ∗) emission excited state.

Synthesis, spectral characterization, thermal and photoluminescence properties of Zn(II) and Cd(II)-azido/thiocyanato complexes with thiazolylazo dye and 1,2-bis(diphenylphoshino)ethane

A series of complexes of the type [M( L)(dppe)X 2]; where M = Zn(II) or Cd(II); L = 4-(2′-thiazolylazo)chlorobenzene ( L 1 ), 4-(2′-thiazolylazo)bromobenzene ( L 2 ) and 4-(2′-thiazolylazo) iodobenzene ( L 3 ); dppe = 1,2-bis(diphenylphosphino)ethane; X = N 3 − or NCS − have been prepared and characterized on the basis of their microanalysis, molar conductance, thermal, IR, UV–vis and 1H NMR spectral studies. IR spectra show that the ligand L is coordinated to the metal atom in bidentate manner via azo nitrogen and thiazole nitrogen. An octahedral structure is proposed for all the complexes. The thermal behavior of the complexes revealed that the thiocyanato complexes are thermally more stable than the azido complexes. All the complexes exhibit blue-green emission with high quantum yield as the result of the fluorescence from the intraligand emission excited state.

Synthesis, characterization and photoluminescence properties of copper(II)–azido/thiocyanato complexes with thiazolylazo dye and1,2-bis(diphenylphosphino)ethane

Abstract A series of copper(II) complexes of the formula [Cu(L)(dppe)(N3)2] (1a–3a) and [Cu(L)(dppe)(NCS)2] (1b–3b) (where L = 4-(2′-thiazolylazo)chlorobenzene (L1); 4-(2′-thiazolylazo)bromobenzene (L2) and 4-(2′-thiazolylazo)iodobenzene (L3); dppe = cis-1,2-bis(diphenylphosphino)ethane) has been prepared and characterized on the basis of their elemental analysis, molar conductance, magnetic moment, IR, UV–vis and 1H NMR spectral studies. The electrochemical behaviour of the complexes showed that the redox responses of copper(II) complexes shifted to more negative potential in order of decrease in electron withdrawing nature of the substituent on the azo ligands. All the complexes exhibit intraligand (π→π*) fluorescence in blue-green region with high quantum yield in DMF solution.

Copper(II) complexes of thiazolylazo dye with triphenylphosphine and or NCS− as coligands: synthesis, spectral characterization, electrochemistry and luminescence properties

A series of copper(II) complexes [Cu(L1 or L2 or L3)(PPh3)2(N3)2] (1a–3a) and [Cu(L1 or L2 or L3)(PPh3)2(NCS)2] (1b–3b) (where L1 = 4-(4′-phenyl,2′-thiazolylazo)chlorobenzene, L2 = 4-(4′-phenyl,2′-thiazolylazo)bromobenzene, and L3 = 4-(4′-phenyl,2′-thiazolylazo)iodobenzene) have been prepared and characterized on the basis of microanalytical data, molar conductances, magnetic moments, UV-Vis, infrared, and ESR spectra. On the basis of electronic spectra and magnetic susceptibility octahedral geometry has been proposed for the complexes. The ESR spectral data provide information about their structures on the basis of Hamiltonian parameters and degree of covalancy. The electrochemical behavior of the complexes showed that the redox responses of Cu(II) complexes shifted to more negative potential with decrease in electron-withdrawing substituents on the azo ligands. Complexes exhibit blue-green emission with high-quantum yield.

Thiazolylazo dyes and their application in analytical methods

An overview is presented on thiazolylazo dyes and their analytical applications in the determination, preconcentration or separation of trace metal ions. The article summarizes conventional analytical methods based on spectrophotometry, solid phase extraction, liquid chromatography and liquid–liquid and cloud point extraction. Both in-batch and on-line procedures are considered. General properties about these ligands are also commented on. Finally, the use of thiazolylazo dyes in procedures involving electroanalytical and other methods is presented.

A Stable Trinuclear Zinc Cluster Assembled from a Thiazolylazo Dye and Zinc Acetate: Preparation, Structural Characterization and Spectroscopic Studies

AbstractA thiazolylazo dye, 5‐(diethylamino)‐2‐(2‐thiazolylazo)phenol (HL), containing potential tridentate binding sites was synthesized in high yield and well characterized. In solution, the reaction of zinc acetate and the deprotonated ligand, L–, results in the instantaneous formation of the supramolecular trinuclear species [Zn3L2(OAc)4] (1). UV/Vis and 1H NMR spectroscopic titration experiments in solution confirmed that the ligand and zinc salt interact spontaneously with each other and produce exclusively the polymetallic complex with the metal‐to‐ligand ratio of 3:2. The crystal structures of both the ligand and coordination complex are reported in this paper. The aromatic part of HL is planar and, significantly, the intermolecular C–H···π hydrogen bonds and thiazo ring‐S···π weak interactions observed here should be responsible for the orthorhombic space group P212121. The structure of 1 reveals a linear trinuclear zinc cluster. The two L– units are linked to three zinc atoms in an N2O tridentate mode, and the four acetate anions are chelated to three metal centers as bridges to result in two pentacoordinate and one hexacoordinate zinc centers. The resulting bridging Zn1–Zn2–Zn1A array is linear by symmetry, with a nonbonding Zn···Zn distance of 3.390 Å and a Zn1···Zn2···Zn1A angle of 180.0°. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Synthesis of new 5-thiazolyl azo-disperse dyes for dyeing polyester fabrics

Diazotized aryl amines were coupled with 2-aminothiazoles 1 and 2 to give the corresponding thiazolylazo dyes 3 and 4, respectively. 2-Amino-5-arylazothiazoles 5 reacted with chloroacetyl chloride to afford the chloro-acetamide derivatives 6 which further reacted with 2-mercaptobenzothiazole to furnish a new series of 5-arylazothiazolyl dyes 7. The azo structure of the dyes (rather than the tautomeric hydrazo structure) was assessed by ab initio DFT calculations at the B3LYP/6-31G* level. These dyes were applied to polyester fabric as disperse dyes and their fastness properties were evaluated.

Metallized thiazolylazo dyes as optical recording materials

A series of metallized thiazolylazo dyes have been designed and synthesized. Smooth films on optical glass and single-crystal silicon were prepared using the spin-coated method. The UV-Vis absorption spectra of the dyes were measured in solution and in films. The optical constant (complex refractive index N= n+ ik) of the films on single-crystal silicon has been determined using a scanning ellipsometer. The variation of the complex refractive index, N, with wavelength, λ, was obtained. From the value of n, k and the thickness of the dye films, the variation of the reflectance vs dye film thickness was then calculated. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) of the nickel thiazolylazo dye showed a clear threshold of thermal decomposition with a sharp exothermic park. Static optical recording tests were carried out. The results show that the nickel thiazolylazo dye is more suitable for use in short-wavelength diode-laser optical recording.

Complex Formation between Monolayers of a Novel Amphiphilic Thiazolylazo Dye and Transition Metal Ions at the Air/Water Interface

The novel amphiphile 5-(octadecyloxy)-2-(2-thiazolylazo)phenol (TARC18) formed a stable condensed type monolayer at the air/water interface. When transition metal ions such as Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) were present in the aqueous subphase, 1:1 complexes of TARC18 with the above metal ions were formed in the monolayers at the air/water interface. The formation of these complexes was verified by measurements of the π−A isotherms and the absorption spectra of the monolayers at the air/water interface in situ. The TARC18 monolayer showed strong ability to incorporate the Cu(II) ion in the subphase, resulting in a larger limiting area and lower collapse pressure of the monolayer on the subphase containing Cu(II) ion in comparison with those on the subphase containing the other metal ions. Moreover, the Cu(II) ion was predominantly bound to the TARC18 monolayer when all the above ions coexisted in the subphase.

Distribution Equilibria of Metal Chelates with Thiazolylazo Dyes between Two Phases Formed from an Aqueous Micellar Solution of a Nonionic Surfactant

A dilute aqueous micellar solution of poly(oxyethylene)=4-nonylphenyl=ether with oxyethylene units of 7.5 (average, PONPE-7.5) was separated into two phases (aqueous and surfactant) at room temperature. The partition constants of thiazolylazo dyes and their metal chelates between the two phases were determined at 293K and an ionic strength of 0.1(NaClO4). Though a linear relationship was obtained between the partition constants of the chelating reagents in the extraction with PONPE-7.5 and those in the ordinary extraction with octanol, such a relationship was not obtained for the chelates. This suggested that the properties of the PONPE-7.5 phase as an extracting solvent were different from those of ordinary organic solvents.

Preparation of soluble ternary heteroazo dye complexes for the spectrophotometric determination of trace uranium(VI)

The complexing ability of typical pyridylazo, quinolylazo and thiazolylazo dyes with uranium(VI) in aqueous ethanol media are investigated in the presence and absence of aromatic carboxylic acid. Uranium(VI) forms solubilized ternary complexes with PAN, PAR, TAM, 5-Br-PADAP, 3,5-diBr-PADAP and QADAP in 48% ethanol solution containing sufficient amounts of sulfosalicylic acid and triethanolamine buffer (pH 7.8). Aromatic carboxylic acids contribute to expel the coordinated water molecules from the uranium (VI) moiety and their chelating effects have been explained by ternary complex formation. An increase in molar absorptivity and no shift in the wavelength of maximum absorbance are observed for all uranium(VI) complexes investigated. The 1∶1 stoichiometry of uranuim(VI) and heteroazo dye in the binary complex does not change through ternary complex formation. The molar absorptivity of the uranium(VI)-3,5-diBr-PADAP-sulfosalicylic acid ternary complex at 595 nm is 8.4×104l mol−1 cm−1 and Beer's law is valid up to 2.5gmg ml−1 of uranium(VI). The interferences due to coexisting metal ions can be effectively masked by addition of CyDTA or Ca-CyDTA.