Synthesis of highly fluorescent coumarinyl chalcones derived from 8-acetyl-1,4-diethyl-1,2,3,4-tetrahydro-7H-pyrano[2,3-g]quinoxalin-7-one and their spectral characteristics

A series of novel coumarin based chalcones were synthesized by the classical crossed aldol condensation reaction of 8-acetyl-1,4-diethyl-1,2,3,4-tetrahydro-7H-pyrano[2,3-g]quinoxalin-7-one and various substituted benzaldehydes. These novel ketocoumarin derivatives having a 1,4-diethyl-1,2,3,4-tetrahydroquinoxaline framework exhibited brilliant fluorescence. The novel chalcones absorbed in the range of 458-523 nm in various solvents. The wavelength of maximum absorption of these chalcones was found to be significantly longer than their simple acyl derivative known in the literature. The dyes displayed longer wavelength of absorption in the high polarity solvents compared to non-polar solvents. Thermogravimetric analysis of the chalcones revealed that the chalcones possess good thermal stability.     

The synthesis and characterization of novel,aza-substituted squarylium cyanine dyes

Several squarylium cyanine dyes derived from benzothiazole, benzoselenazole and quinoline were synthesised and the central four member ring functionalized by substitution of one of the oxygen atoms by benzylamine, aniline, 3-iodoaniline, N,N-dimethylhydrazine and 2-aminosulfonic acid groups. All of the ensuing, novel aza-substituted dyes displayed strong absorption within the range 651–709 nm.     

Visible absorption spectra of some novel heteroarylazo disperse dyes derived from 2-hydroxy-1,4-naphthoquinone

Synthesis of eight novel heteroarylazonaphthoquinone dyes has been carried out by diazotisation of a range of heterocyclic amines in nitrosyl sulphuric acid and coupling these on to 2-hydroxy-1,4-naphthoquinone. The dyes have been characterised by elemental analysis and spectroscopic methods. The effect on the visible absorption spectrum of the substituents present, and external influences such as solvents, pH and temperature, has been investigated in detail.     

Organosoluble semi-alicyclic polyimides derived from 3,4-dicarboxy-1,2,3,4-tetrahydro-6-tert-butyl-1-naphthalene succinic dianhydride and aromatic diamines: Synthesis,characterization and thermal degradation investigation

Semi-alicyclic polyimides (PI-1–PI-4) have been prepared from a newly-developed alicyclic dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-6-tert-butyl-1-naphthalene succinic dianhydride (TTDA) and various aromatic diamines. The asymmetrical alicyclic tetralin structure in TTDA endowed the derived PI resins good solubility in various organic solvents. They were soluble not only in polar aprotic solvents but also in solvents with low boiling points including dichloromethane and tetrahydrofuran. Flexible and tough PI films were successfully cast from their N-methyl-2-pyrrolidone (NMP) solution except PI-1 derived from TTDA and 4,4′-oxydianiline (ODA). The PI films exhibited good optical transparency in the ultraviolet and visible light region with optical transmittances around 80% at a wavelength of 400 nm. The PI films showed good thermal stability up to 400 °C in nitrogen, after that they thermally decomposed rapidly. The thermal degradation behaviors of the PIs were investigated by means of thermogravimetric analysis-mass spectrometry (TG-MS), thermogravimetric analysis-Fourier transform infrared spectrometry (TG-FTIR) and the real time FTIR spectra (RT-FTIR) analysis techniques. The results revealed that the decomposition of PI-1 (as a representative) took place mainly in the range of 450–550 °C. The major degradative fragments at 500 °C were clearly identified as the tert-butyl-substituted tetralin moiety and its dealkylation products. Therefore, it can be deduced that for the TTDA-PIs, the single bond bridge attached the maleic anhydride and tetralin anhydride units in TTDA moiety might break first during the heating; thus producing the tetralin fragments.     

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.     

空气氧化一锅法合成1,2,3,4-四氢吲哚[2,3-b]喹喔啉

为了探索喹喔啉新的合成路线,以吲哚醌和环己二胺为原料,在空气中氧气的作用下合成了1,2,3,4-四氢-6H-吲哚[2,3-b]喹喔啉,共合成衍生物12个,产率为39%~70%,所合成的化合物通过红外、核磁、质谱进行了表征。结果说明合成了目标产物。此外,对化合物9-氟-1,4-二氢-6H-吲哚喹喔啉(Ⅰl)和9-甲基-1,4-二氢-6H-吲哚喹喔啉(Ⅰm)进行了X射线衍射测试,对晶体结构进行了分析。     

A novel fluorescent bisazomethine dye derived from 3-hydroxyquinoxaline-2-carboxaldehyde and 2,3-diaminomaleonitrile

A novel bisazomethine Schiff base was synthesised by the condensation of 3-hydroxyquinoxaline-2-carboxaldehyde and 2,3-diaminomaleonitrile. ¹H NMR, ¹³C NMR, HPLC and FT-IR studies revealed that the compound exists in two major tautomeric forms. The Schiff base exhibits positive absorption and fluorescent solvatochromism and displays dual fluorescence with large stoke shifts. Cyclic voltammetric analysis of the compound in 1:1 methanol–THF was influenced by scan rate. Thermal analysis of the compound was undertaken using TG–DTA and DSC.     

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.     

The synthesis, characterization, thermal and optical properties of copper, nickel, and vanadyl complexes derived from azo dyes

Two, novel, tetradentate Schiff-base ligands, namely bis-5-phenylazosalicylaldehyde diethylenetriimine and bis-5-[(4-methoxyphenyl)azo]salicylaldehyde diethylenetriimine, as well as their Cu²⁺, Ni²⁺, and VO²⁺ complexes, were synthesized and characterized using elemental analysis, infrared and also UV–Visible spectroscopy, ¹HNMR and mass spectra. The thermal stability of the free ligands and the related metal complexes, as determined using differential scanning calorimetry and thermal gravimetric analysis, were found to be thermally stable upto 240–275 °C depending on the type of ligand and the central metal atom. The λ_max of the ligands and their transition metal complexes in the region 300–800 nm are discussed. The novel metal complexes offer potential for application as recording media owing to both their absorption spectra in the blue-violet light region and high thermal stability.     

Synthesis and characterization of novel polymers derived from gluconolactone

A novel synthesis of vinyl monomers derived from D ‐gluconolactone, an interesting precursor obtained from D ‐glucose, is reported. The derivatization of D ‐gluconolactone is carried out by first reacting methacrylic acid with a diamine in water, followed by in situ amidation of the sugar compound. Three monomers containing different lengths of alkylamido groups between vinyl and sugar residues, have thus been obtained and homopolymerized with various free‐radical initiators. The resulting polymers were analysed by viscometry and were found to exhibit polyelectrolyte behaviour. Their structures were confirmed by NMR and consist of a predominantly syndiotactic structure. Copolymerization of the gluconamidoalkyl ammonium methacrylates with other hydrophilic monomers such as methacrylamide and vinylpyrrolidone was also achieved. © 2001 Society of Chemical Industry     

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.     

Development of novel fluorescent offset ink based on coumarin dyes: Synthesis and properties

Novel fluorescent inks based on coumarin dyes used in offset printing techniques were developed, and their considered chemical and physical properties were investigated. First, the influences of very long alkyd resin, maleic varnish, and phenolic varnish substrates and dye concentrations on the fluorescence properties of these dyes, and secondly, the effects of the presence of fluorescent dyes on the physical properties of inks were examined. Accordingly, two offset inks were prepared: one with an obtained optimum formulation possessing the strongest fluorescence emission in alkyd resin and maleic varnish with a weight ratio of 60:40, and one without fluorescent dyes. Their physical properties, such as rheological behavior, tack, and ink-in-water emulsification, were studied. Both inks showed Newtonian behavior, and the dye induced small increases in the viscosity, thixotropy, and tack values of the fluorescent ink.     

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 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.     

Synthesis and characterization of sulphonated polymer derived from 6FDA-ODA polyimide

Summary 6FDA-ODA polyimide was sulfonated with concentrated sulfuric acid at room temperature in order to convert the polymer into proton-conducting polymer. The sulfonation process was supervised with UV-vis. The results indicated that the reaction carried out quickly and was agreement with the analysis of resulted polymer. The sulfonation degree can be controlled by reaction time. The structure of the resulted polyelectrolytes were analyzed and confirmed by NMR, FT-IR. There are two weight-loss steps at 300 and 500 °C in TG curves, which correspond to the presence of two degradation processes for –SO₃H and polymer backbone. It indicated that the sulfonated polyimide had good thermo stability. The solubility of sulfonated polymer are also discussed.     

The synthesis and characterization of novel carboxyl telechelic microspheres

A series of novel carboxyl telechelic microspheres (CTMs) with different length of oligo-caprolactone telechelic chains are readily prepared via a three-step approach involving: (1) the hydrolytic oligomerization of ε-caprolactone, (2) the esterification of oligo-caprolactone with maleic anhydride, and (3) the suspension polymerization of maleic acid polycaprolactone ester acid (MAPCLA) with divinylbenzene. The CTMs, which are water swellable, spherical, and porous, contain carboxyl functionalities of 1.0 to 4.2 mEq/g (dry), which are found to be lower swelling change (during conversion of ionic form) and higher exchange efficiencies than those of the Emerk. IV resin. The intermediate products, oligo-caprolacton, and MAPCLA are characterized by the acid–base titration, hydroxyl value titration, and infrared and ¹H nuclear magnetic resonance analysis, respectively. The morphology and porous of CTMs are also tested by scanning electron microscopy and Brunauer-Emett-Teller technology. The effects of the length of the telechelic chains and the degree of crosslinking (divinylbenzene), as well as the amount of porogen (toluene), on the physical and chemical parameters of the CTMs are also described. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:205–216, 1998     

The synthesis,crystal structure and photophysical properties of three novel naphthalimide dyes

Three new naphthalimide derivatives containing an electron-donor moiety (carbazole), 4-carbazolyl-N-methyl-1,8-naphthalimide, 4-carbazolyl-N-cyclohexyl-1,8-naphthalimide and 4-carbazolyl-N-phenyl-1,8-naphthalimide were synthesized and crystal structures confirmed. Crystallographic data revealed that the interplanar angles (θ) of the carbazole and naphthalimide moieties were, respectively, 70.7° and 66.5°. The UV–vis absorption and photoluminescent spectra of the systems in n-hexane, CHCl₃, tetrahydrofuran and CH₂Cl₂ were investigated. The lowest absorption band of the naphthalimide molecular centered at 400–420 nm was assigned to charge-transfer transition with emission at ≈440 nm in n-hexane and at ≈560 nm in CH₂Cl₂.     

The relationship between solid-state fluorescence intensity and molecular packing of coumarin dyes

The solid-state fluorescence intensity of coumarin dyes depends on the substituents present at the 4- and 7-positions. 7-(Diethylamino)coumarins showed higher solid-state fluorescence quantum yield (Φ_f(ss) = 0.29–0.40) than 7-aminocoumarins (0.01). In the case of julolydyl coumarins, a 4-methyltetramethyljulolydyl derivative also displayed high Φ_f(ss) (0.34), this being greater than that observed for both 4-(perfluoroalkyl)tetramethyljulolydyl (0.09 and 0.10) and 4-methyljulolydyl derivatives (0.01). X-ray crystallographic analysis suggested that coumarin dyes bearing network hydrogen bonds and/or π–π stacking show weak solid-state fluorescence whereas coumarin dyes having isolated monomer- and dimer-type stacking show intense fluorescence. 4-(Perfluoroalkyl)tetramethyljulolydyl derivatives displayed medium fluorescence intensity owing to isolated monomer-type packing with little intermolecular interactions operating between adjacent molecules.     

Polyimides derived from nonaromatic monomers: synthesis, characterization and potential applications

A number of mixed aromatic/cycloaliphatic as well as fully nonaromatic polyimides have been prepared. Whereas all the poly(amic acids) derived from nonaromatic diamines involved salt-formation during the initial stages of the polymerization, the majority of these eventually formed homogeneous, highly viscous polymer solutions. Only in a few select cases involving all nonaromatic monomers traditional solution polymerization was unsuccessful. The polyimide derived from hexafluoroisopropylidene diphthalic anhydride (6FDA) and trans- 1,4-diaminocyclohexane (DACH) yielded films with tough mechanical properties, a glass transition temperature of 360°C, good solvent resistance, and a low dielectric constant of 2.6. Thermal stability of this polyimide as determined by thermal gravimetric analysis in both air and nitrogen was quite good, exhibiting a weight loss of only 0.07 wt%/h at 350°C under isothermal conditions in nitrogen. However, mechanical properties as a function of thermal aging in both air and nitrogen indicated a maximum use temperature of only 350°C under inert conditions and less than 300°C in the presence of oxygen.     

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.