Synthesis, spectral characterisation and antimicrobial activity of new disazo dyes derived from heterocyclic coupling components

Two series of new disazo dyes were prepared by diazotising 4,4'-diaminodiphenylsulphonamide and 4,4'-diaminodiphenylurea and coupling with 3-methyl-1-phenyl-pyrazoline-5-one, 2-methylindole, 8-hydroxyquinoline, 2-phenylindole, 1-methyl-2-phenylindole, 3-amino-1-phenyl-pyrazoline-5-one. These dyes were characterised by ultraviolet–visible, Fourier transform infrared, nuclear magnetic resonance spectroscopic techniques and elemental analysis. The spectral characterisation of the dyes was evaluated with respect to visible absorption properties in various solvents. The effects of acid and base on the visible absorption maxima of the dyes were also reported. In addition, the antimicrobial effect of the dyes was evaluated.     

Synthesis,spectral properties and application of novel disazo disperse dyes derived from polyester waste

Terephthalic dihydrazide was obtained through aminolytic depolymerisation of polyester bottle waste by using hydrazine hydrate. It was further reacted with 4‐aminobenzoic acid in the presence of polyphosphoric acid to obtain a cyclic compound, 4,4′‐[5,5′‐(1,4)‐phenylene)bis(1,3,4‐oxadiazole‐5,2‐diyl)dianiline, having a heterocyclic moiety. Diazotisation of this compound followed by coupling with various N,N‐disubstituted anilines afford a series of novel disazo disperse dyes. The structures of these synthesised dyes were confirmed by elemental analysis and Fourier Transform–infrared, proton nuclear magnetic resonance and mass spectroscopy. Ultraviolet–visible spectra of these azo dyes in different polar solvents showed considerable variation in the wavelength of maximum absorbance (λ_max). Application of these dyes on polyester and nylon fabrics using high‐temperature dyeing methods gave brilliant yellowish red hues with fair to moderate light fastness and very good to excellent wash fastness and sublimation fastness.     

The synthesis,antimicrobial activity and absorption characteristics of some novel heterocyclic disazo dyes

Aniline derivatives were diazotized and coupled with 3-aminocrotononitrile to give the corresponding 2-arylhydrazono-3-ketiminobutyronitriles. Cyclization of these arylhydrazono derivatives with hydrazine monohydrate afforded 5-amino-4-arylazo-3-methyl-1H-pyrazoles which were subsequently diazotised and coupled with malononitrile to yield a series of pyrazolylhydrazonomalononitriles. These compounds were then reacted with hydrazine monohydrate to provide 10, novel, heterocyclic disazo dyes, which were characterized by elemental analysis and spectral methods. The antimicrobial activity and absorption characteristics of the dyes were also examined in detail.     

Dyeing of poly(lactic acid) fibres with synthesised novel heterocyclic disazo disperse dyes

Poly(lactic acid) (PLA) is the first melt‐processable, renewable, sustainable and biodegradable natural‐based synthetic fibre. It has a broad range of uses and combines ecological advantages with outstanding performance in textiles. PLA fibre, as an aliphatic polyester, can be dyed with disperse dyes. Apart from the limited number of commercial disperse dyes, disperse dye exhaustion on PLA is generally lower than that on  poly(ethylene terephthalate) (PET). In this study, new heterocyclic disazo disperse dyes, substituted with methyl, nitro and chloro groups at their ortho‐, meta‐ and para‐ positions, synthesised in our previous study, were applied to PLA and PET fibres to examine their dyeing performance, and colour fastness and dye exhaustion properties. Different shades of yellow, orange, reddish brown and brown were obtained. Most of the synthesised novel heterocyclic disazo disperse dyes exhibited good build‐up properties with high K/S levels on both fibres. Para‐ bonding substituent provided higher K/S values than meta‐ and ortho‐ positions for –NO₂ and –Cl substituents for both fibres. Overall, the most synthesised novel heterocyclic disazo disperse dyes in this study exhibited good build‐up properties with high K/S, exhaustion and wet fastness levels on both PLA and PET fibres.      

Synthesis of some new heterocyclic systems derived from 2-acetylbenzimidazole

The named compound was reacted with thiosemicarbazide and/or semicarbazide to produce the corresponding condensation products II and V respectively. Reaction of II with chloroacetic acid in ethanol containing anhydrous sodium acetate yielded III. Condensation of III with aromatic aldehydes yielded the corresponding arylidene derivatives (IV). Oxidation of the semicarbazone V with selenium dioxide gave 2-(1,2,3-selenadiazole-4-yl)benzimidazole (VIa, b) while with thionyl chloride it gave 2-(1,2,3-thiadiazole-4-yl)benzimidazole (VIIa, b). The chalcones of 2-acetyl and/or 1-methyl-2-acetylbenzimidazole were condensed with hydrazine hydrate, phenylhydrazine and/or hydroxylamine to produce 2-(5-aryl-1(H)-pyrazolin-3-yl)-, 2-(5-aryl-1-phenyl-2-pyrazolin-3-yl)- and 2-(5-aryl-2-isoxazolin-3-yl)benzimidazole (IX, X, XI) respectively.     

Synthesis and spectroscopic properties of novel azo dyes derived from phthalimide

A set of azo dyes has been synthesised using N -substituted phthalimides as diazo components. 3,5-Dibromo- N -substituted-phthalimidylazo derivatives were cyanated by cyanodehalogenation to give dicyano analogues. All of the synthesised intermediates and dyes have been characterised by mass spectrometry, ¹H-NMR or elemental analyses. The gamut of colour of the prepared dyes spanned much of the visible spectrum: absorption maxima of the dyes in formamide were observed in the range 436 to 609 nm. Consistent with results seen in previous studies of non-phthalimido monoazo disperse dyes, replacement of dibromo groups with dicyano functions in the phthalimide-based set led to large bathochromic shifts in absorption maxima, as did the introduction of acetylamino groups onto the coupler ring ortho to the azo link. However, switching an N -propyl function on the imido ring for a benzyl or 3-cyanopropyl substituent had little effect on absorption maxima. Good correlations between the observed absorption maxima of certain dyes and those of model analogues predicted by Pariser–Parr–Pople molecular orbital calculations were observed when steric effects were absent.     

Synthesis of disperse dyes derived from 1-Cyano-2-substituted-3-azabenzanthrones

Several disperse dyes have been synthesized by reaction of 6-chloro-1-cyano-2-substituted-3-azabenzanthrones by Ullmann reaction with various amines. The dyes thus obtained have been examined for their absorption characteristics and their dyeing behaviour on polyester.     

五元杂环取代BODIPY染料的合成及光谱性能研究

以吡咯和2-呋喃甲醛、2-噻吩甲醛为原料,经缩合、氧化、环化反应合成了含新型五元杂环的BODIPY荧光染料,进一步溴化分别得到两种一溴代染料,所有合成的染料分子均通过质谱、核磁等手段进行了结构表征,并测试了这些染料的吸收光谱和发射光谱.结果表明:所有染料随着溶剂极性的增大表现出一定的溶剂化效应,吸收和发射波长变化不大(...     

Dyeing of polyester and its blends with some disazo dyes derived from the disodium salt of chromotropic acid and their chelates with transition metal ions

Disazo dyes derived from the disodium salt of chromotropic acid and their chelates with metal ions were applied on polyester, polyester/cotton and polyester/wool blend fibres as disperse dyes. The fastness to washing, perspiration, rubbing and light of the resultant dyeings were measured. The bonding of dye or its complexes to the fibre and the effect of substituent groups on the colour fastness of the dyes are discussed.     

The synthesis and characterization of heterocyclic azo dyes derived from 5-N,N-dialkylamino-2,2′-bithiophene couplers

Heterocyclic azo dyes were synthesized by diazotation of several substituted anilines and coupling with 5-N,N-dialkylamino-2,2′-bithiophenes to give 4-phenylazo-5-N,N-dialkylamino-2,2′-bithiophenes. This reaction contrasts with the behavior of 5-alkoxy-2,2′-bithiophenes towards aryldiazonium salts which provides 5-phenylazo-5-alkoxy-2,2′-bithiophenes. The thermal stability of the derivatives was evaluated using thermogravimetric analysis and their solvatochromic behaviour was investigated in several solvents of different polarity. The experimental results indicate that the heterocyclic azo dyes could be used as thermally stable, solvatochromic probes.     

Cyanine dyes of new heterocyclic ring systems: Synthesis and structure-spectra studies

New cyanine dyes including monomethine cyanine dyes (simple cyanine dyes) and trimethine cyanine dyes (carbocyanine dyes) incorporating benzo[2,3-b; 2′,3′-b′]bispyrazolo[4,5-b]-1,4-(oxa-, thia-, and pyra)-zine-6,12-dione were prepared. Structure-spectra studies were carried out via measuring the electronic visible absorption spectra of these dyes in 95% ethanol. Structural confirmations were determined through elemental analysis, IR, ¹H NMR spectroscopy and MS spectral data at the Micro Analytical Center, Cairo University.     

Synthesis, absorption characteristics and solvatochromism of some novel heterocyclic cyanine dyes

Novel heterocyclic monomethine, bis monomethine, trimethine and bis trimethine cyanine dyes incorporating benzo [2,3-b; , - ] bis furo [3,2-d] pyrazole nuclei were synthesised. The absorption characteristics of the prepared cyanines were studied and determined through measuring their electronic visible absorption spectra in 95% ethanol. The solvatochromism of some of the synthesised dyes was investigated.     

Novel azo dyes derived from phthalimide. Part 1: Synthesis and spectroscopic properties

A series of azo dyes has been synthesised based on N -alkylphthalimide diazo components featuring one of three different alkyl groups. An analogous set of dyes was prepared in which the N -alkylphthalimidylazo systems bore an o,o -dibromo-substitution pattern. In these cases, cyanodebromination was performed to give the corresponding dicyano analogues. All the synthesised intermediates and dyes were characterised by mass spectrometry, proton nuclear magnetic resonance spectroscopy and elemental analysis. The absorption maxima of the dyes in dimethylformamide (N,N-dimethyl ∼) were observed to be in the range 435–608 nm and found to be consistent with results seen in previous studies of conventional monoazo disperse dyes. Replacement of both halogens in the dibromo-substituted dyes with cyano groups led to large bathochromic shifts (128–141 nm) in absorption maxima. Bathochromism was also observed when acetylamino groups were present on the coupler ring ortho to the azo link. However, variation of the N -alkyl function on the imido ring from n -butyl to sec -butyl and iso -propyl had little effect on absorption maxima, values being similar to that reported for the parent N -unsubstituted analogue.     

Monoazo disperse dyes derived from mononitro-dichloro-2-aminobenzothiazoles

Nitration of dichloro-2-aminobenzothiazoles afforded the corresponding mononitro derivatives. Diazotisation of these and coupling to N-substituted anilines gave red to reddish-blue dyes for polyester. The colour of the dyes is discussed with respect to the relative orientation of the nitro and chloro substituents. Data on dyes from a trichloro- and a nitro-trichloro-2-aminobenzothiazole are also reported.     

Synthesis and properties of some novel pyrazolone-based heterocyclic azo disperse dyes containing a fluorosulfonyl group

A series of heteroarylazo disperse dyes derived from pyrazolones and fluorosulfonyl anilines were synthesized, and their thermal and spectral properties were investigated with respect to the effect of substituents on absorption spectra, halochromism, and solvatochromism. Heteroarylazo disperse dyes, which contain a nitro group instead of a fluorosulfonyl group para to the azo group in the diazo component, were also synthesized for comparative purpose. The fluorosulfonylarylazopyrazolone dyes had absorption maxima at shorter wavelength and showed lower extinction coefficients than the nitroarylazopyrazolone dyes. The synthesized dyes also exhibited positive halochromism and solvatochromism, so the absorption bands of the dyes moved toward longer wavelengths as the acidity or polarity of the solvent increased. 4-Fluorosulfonyl-substituted dyes generally showed lower thermal stability than their 4-nitro-substituted analogs, because the lower electron-withdrawing power in the diazo components tended to decrease the polarizability and dipole interactions.     

The light fading mechanism of dyes derived from rhubarb extract

The effect of relative humidity and mordanting on the fading kinetics and colour change of dyes derived from rhubarb extract on wool and silk has been investigated. Wool samples showed negligible change in colour even after 100 h of exposure, whereas silk samples became significantly darker. Relative humidity in the range of 10–45% and mordanting did not appear to affect the rate of fading on both the fibres. However, the rate and extent of change in colour (ΔE) on exposure was different for different mordants. The high resistance of the dye to light fading indicates that the dye is present in a highly aggregated form in silk and wool.     

Novel heterocyclic intermediates for new dyes and pigments

The synthesis of two new heterocyclic ring systems of the phenoxazine type is described. These are the 1,4,9-triazaphenoxazine and 1,4,6-triazabenzo[b]phenoxazine. The preparation of the parent ring of 1,4,9-triazaphenoxazine ring system is also reported. Spectroscopic data are in agreement with the assigned structures and the mechanistic pathway to these novel heterocycles is also presented. These ring systems provide a new framework for the development of novel dyes and pigments of the phenoxazine class.     

PZT components derived from polysulphone spinning process

The present paper deals with the development of lead zirconate titanate (PZT) fibres, pearls and fibre fragments, for their use as active phase in piezocomposites. As new a approach, the green ceramic components are shaped by polysulphone spinning, allowing for effective and flexible forming over a wide range of different geometries and sizes. The correlation between processing parameters, e.g. the slurry composition, nozzle size and operation velocity, and the resultant shape of ceramic components is analysed. Sintered piezoceramic parts show a dense microstructure. Performance data are evaluated on PZT/epoxy composites. Measurement results of strain, polarisation and piezoelectric coupling are given and discussed. The developed PZT components are seen as key for the creation of smart and lightweight structural components. Further, free formed PZT components open new design approaches for sensing and actuating devices and ultrasound transducers.     

Synthesis and electronic spectra of some azo disperse dyes derived from N-2,2,2-trifluoroethyl-1,2,3,4-tetrahydroquinoline

Several monoazo dyes suitable for transfer printing have been prepared from N-2,2,2-trifluoroethyl-1,2,3,4-tetrahydroquinoline and compared with their N-ethyl counterparts. The presence of a trifluoroethyl group brings about considerable improvements in lightfastness properties on both polyester and nylon. Electron withdrawal by the trifluoroethyl substituent leads to hypsochromic shifts of the visible absorption band and also results in a marked positive halochromism.