Color Formers Research Articles

Liquid chromatography–mass spectrometry analysis of dyes formed by in situ oxidative methods then purified by absorption and extraction from hair wefts

The dye mixtures formed from three commercial hair colour formers were purified by absorption onto human hair wefts, washed and dried, extracted with dichloromethane:trifluoroacetic acid (75:25) and then analysed by liquid chromatography–mass spectrometry. Only 1–2 dyes were identified from each complex mixture of commercial aromatic amines along with a broad UV absorption mainly consisting of mixtures of quaternary ammonium salts from shampoos and some surfactants. Mecetronium ethyl sulfate and didecyldimethylammonium chloride were the main ammonium salts.

Optical and structural dynamical behavior of Crystal Violet Lactone – Phenolphthalein binary thermochromic systems

Several binary composites based on Crystal Violet Lactone (CVL) color former and Phenolphthalein (PPht) developing agent dissolved in 1-tetradecanol (TD) were studied in order to determine how different ratios between components influence the thermochromic behavior of the composites. The color dependence on temperature was investigated in direct relationship with structural changes and interactions between components. The stoichiometry of the colored complex was determined from diffuse reflectance data and confirmed by means of steady state fluorescence measurements and temperature modulated differential scanning calorimetry. The color former: developing agent molar ratio equal to 1:2.5 was determined to ensure the reversibility of the process in optimal conditions. The characteristics of the color path and the influence of thermal history during thermochromic transition were analyzed from the variations of CIELAB color parameters during successive heating/cooling cycles. Dynamic colorimetric properties of the thermochromic binary composite containing the components in optimum ratio are described by four characteristic temperatures in the hysteresis.

ChemInform Abstract: Syntheses and Properties of Pyridocarbazole Quinonoid-Type Near-Infrared Colour Formers.

New pyridocarbazole quinonoid-type colour formers that can immediately produce intense absorption bands in the near-IR region on simultaneous metal chelate complexation-oxidation processes are synthesised.

Reversible multi-coloring reaction of spironaphtooxazine controlled by long-chain molecule

A novel reversible multi-colored (red, violet, blue and yellow) film was realized using a typical photochromic dye (the color former) and docosylphosphonic acid (the color developer). A mixture of the color former/color developer exhibiting reversible multi-coloring reactions was controlled by heat-treatment of the solid phase. The structure and crystalline state of the film mixtures were investigated by UV–vis spectroscopy, X-ray diffraction and high-resolution electron diffraction measurements. The color of the films was controlled by the structural type of the photomerocyanine-form (protonated zwitterionic, zwitterionic and quinoid). The mechanism of the multi-coloring reaction was concluded to be the chemical combination of color formers and color developers, which produces red and violet colors, and when the coloration-temperature acts to separate the color formers from the color developers, yellow color appears. Furthermore, the color of the film changed from yellow to blue upon 360 nm light irradiation.

A Novel Color Former Organogel for Radiation Detection Systems

Abstract A novel leuco phenoxazine color former containing l-phenylalanine at the protecting group was prepared for radiation detection systems. It forms elongated self-assembled fibers in common organic solvents, leading to that efficient gelation. FE-SEM and FT-IR of the xerogel showed the color former formed a three-dimensional net-like structure. The color former organogel showed sufficient sensitivity to γ rays that it can be used for imaging in heavy particle radiotherapy and has good potential for three-dimensional radiation detection systems.

Modifications of Color Formers for Placement in Different Layers in a Single-Sheet Thermal Imaging System

A single-sheet multilayer thermal imaging system consists of three color-forming layers comprising materials that are transformed from a colorless crystalline form to a colored amorphous form by heating. The color-forming layers are separated by thermally insulating layers, allowing for independent addressing of each color-forming layer (i.e., without any undesired color formation in other layers). The temperature required for the conversion from the colorless to the colored form is different for each of the color-forming layers. It may be difficult, however, to find suitable color-forming molecules having the right properties for image formation (e.g., chromophore and stability characteristics) as well as an optimum melting temperature. Incorporation of additional components into the color-forming layers allows the placement of the same color-forming crystalline material in any layer of the imaging system, eliminating the constraint of its intrinsic melting temperature.

Quality and shelf life of packaged fresh sliced mushrooms stored at two different temperatures

The sensory and microbiological quality of sliced mushrooms (Agaricus bisporus L.) packaged in films of perforated and non-perforated PVC and stored at 3 and 9ºC, was studied. The carbon dioxide and oxygen content inside the packages, colour, weight loss, sensory attributes, mesophiles, Pseudomonas, Enterobacteriaceae, aerobic and anaerobic spore formers were determined. The atmosphere generated with the perforated PVC film was similar to that of air atmosphere at 3 or 9ºC. T.he non-perforated PVC film generated inside the packages CO2 : O2 concentrations of 3.4% : 8.1% at 3ºC and CO2 : O2 concentrations of 4.5% : 0.15% at 9ºC. Browning of mushrooms was lower at 3 than at 9ºC. The quality of sliced mushrooms packaged in perforated PVC and stored at 3ºC was adequate after 9 days. However, at 9ºC, the slice deformation and brown blotches incidence were severe after 9 days. The atmosphere generated with non-perforated PVC inhibited aerobic microorganism growth compared to mushrooms packaged in perforated PVC. At 3ºC, the shelf life of mushrooms packaged in non perforated PVC was around 13 days. However, the extremely low O2 atmospheres generated at 9ºC was accompanied by off-odours and growth of anaerobic spore formers, although the appearance of sliced mushrooms was acceptable.;

Modifications of Color Formers for Placement in Different Layers in a Single-Sheet Thermal Imaging System

A single-sheet multi-layer thermal imaging system consists of three layers of color-forming components, which are transformed from a colorless crystalline to a colored amorphous form during the imaging process. The temperature required for the conversion to the colored form is different for each of the color formers. These color-forming layers are separated by thermally-insulating layers that are required for addressing each color-forming layer independently, without any undesired color formation in other layers. The conversion temperatures of the crystalline materials can be altered by incorporation of additional components into the color-forming layers. Such additional components allow the placement of the same color-forming, crystalline material in different layers of the imaging system, eliminating the constraint of its intrinsic melting temperature.

Photostabilization of Leuco Dyes: Counter-ion Effect on the Light Fastness of Color Formers

Color formers are given considerable attention as functional dyes for heat- and/or pressure-sensitive recording media and printed textiles. Numerous potential metal complexes were synthesized to prolong the life of colored species. The protecting effect of these compounds against the photofading was examined on cellulose. It was found that the zinc or nickel salts of hydroxyarylcarboxylates bearing an amphoteric counter-ion effect can be applied as effective stabilizers against the fading of color formers.

Photostabilization of organic thermochromic pigments. Part 2: Effect of hydroxyarylbenzotriazoles containing an amphoteric counter-ion moiety on the light fastness of color formers

Color formers are extensively used in information-recording systems or thermochromic systems for textiles, but their light fastness properties are poor; improvement of light fastness is therefore being sought. Various kinds of stabilizer were synthesized in an attempt to prolong the life of colored species derived from color formers. The retarding effect of these compounds towards photofading was investigated on cellulose. It was found that hydroxyarylbenzotriazoles bearing groups that are capable of acting as amphoteric counter-ions play an important role in improving the light fastness of colorants for imaging and data-recording systems. Both zinc and nickel 3-(2-benzotriazolyl)-2-hydroxy-1-naphthoates and derivatives are proposed as effective stabilizers against the fading of color formers.

Photostabilization of organic thermochromic pigments: Action of benzotriazole type UV absorbers bearing an amphoteric counter-ion moiety on the light fastness of color formers

Color formers are extensively used in information recording systems or thermochromic systems for textiles, but their light fastness properties are poor. The improvement of light fastness is therefore being sought at the present time. Various kinds of stabilizers have been synthesized to prolong the life of colored species derived from color formers. The retarding effect of these compounds towards photofading was investigated on cellulose. It was found that the UV absorbers bearing the groups capable of acting as an amphoteric counter-ion play a very important role in improving the light fastness of colorants for imaging and data recording systems. Zinc and nickel 5-(2-benzotriazolyl)-2,4-dihydroxybenzoates and the derivatives have been proposed as effective stabilizers against the fading of color formers.

Synthesis and Radiation Sensitivity of Phenoxazine Type Color Formers Including Thiol Ester Protective Group

ABSTRACT 3,7-Bis(N,N-diethylamino)-10-(phenylthio)carbonylphenoxazine (1a) and its analogs (1b–f) were synthesized and the color change after γ irradiation was investigated. The color change of acetonitrile solutions of 1a ([1a]0 = 1.0 × 10−3 M) after γ irradiation was identified by naked eyes at the dose of 20 Gy. Phenylthio-substituted compound 1a showed more significant absorbance increase than phenoxy-substituted compound, 3,7-bis(N,N-diethylamino)-10-phenoxycarbonylphenoxazine (2a). The C‒S cleavage in 1a by γ irradiation was revealed to occur more easily than the C‒O cleavage in 2a. The sensitivity of the color formers (1a–f) to γ rays was correlated with the stability of the thiyl radicals generated in the reaction.

Molecular Design, Synthesis and γray Detection of Novel Color Formers Having

Novel color formers 2 containing phenazine moiety for γray detection were designed based on the shades of chromophore 1. Color formers 2a-2c were synthesized from aromatic amines 4, 5 and 6 or dye 9·Cl- or 10·Cl- as starting materials. Acetonitrile solution of 2a, 2b or 2c was changed into corresponding colored form 1a-1c by γirradiation. Identification of the structures of 1 was carried out with electronic absorption and mass spectrometry. 1a, 1b or 1c showed magenta, red or yellow shade respectively. Substituent R1-R4 introduced into 1 affected a remarkable shift of absorption maximum within visible range.

Development of a Polymer Film Containing a Leuco-Phenoxazine Color Former for .GAMMA. Ray Detection

A polymer film containing a leuco-phenoxazine color former, 3,7-bis(N,N-diethyl amino)-10-(2,2,2-trichloroethoxycarbonyl)phenoxazine (1) was fabricated for the detection of γ rays. The colorless film containing 1 tinged with blue by γ irradiation. Polymethyl methacrylate (PMMA, 3) film containing 10 wt% of 1 (thickness: 0.8 mm) gave remarkable color change at a dose of 10 Gy. The absorbance change at 644 nm observed in the PMMA film containing 1 after ? irradiation was 3.7 times larger than that at 658 nm in the polystylene (PS, 4) film. The PMMA film was stable at room temperature in a dark place for at least 30 days. Thus, sensitive, thermal-stable, and easy handling γ ray detection system is realized.

New developments in the stabilization of leuco dyes: effect of UV absorbers containing an amphoteric counter-ion moiety on the light fastness of color formers

Color formers are extensively used in information recording systems or thermochromic systems for textiles, but their light fastness properties are poor. The improvement of light fastness is therefore being sought at the present time. Various kinds of stabilizers have been synthesized to prolong the life of colored species derived from color formers. The suppressing effect of these compounds towards photofading was investigated on cellulose. It was found that the UV absorbers bearing the groups capable of acting as an amphoteric counter-ion play very important role in improving the light fastness of colorants for imaging and data recording systems. Zinc and nickel 2,4-dihydroxybenzophenone-3-carboxylates have been proposed as effective stabilizers against the fading of color formers.

Chromophoric potential of the 4(3H)‐quinazolinones: a review

The last few decades have seen significant developments in the use of heterocyclic compounds in dyestuff and pigment chemistry. The design of newer heterocyclic systems has been a major target area and has focused on economically viable synthesis, absence of effluent problems and freedom from carcinogenic and mutagenic effects. The present article reviews the chemical and patent literature on the chromophoric potential of the 4(3H)‐quinazolinone ring system, including dyes, pigments, fluorescent brightening agents, luminescent inks, electroluminescent devices, photographic couplers, colour formers and photographic fog inhibitors.

Development of Novel Color Former Containing Phenoxazine Moiety

A novel phenoxazine color former, 3, 7-bis(N, N-diethylamino)-10-(2, 2, 2-trichloroethoxycarbonyl)phenoxazine (1), was synthesized. Acetonitrile solution of colorless 1 was observed to give blue cation 2a by γ irradiation of 10 Gy. Little absorbance changes were observed when the blue shade solution was kept for 6 d after γ irradiation. Compound 1 showed excellent sensitivity to γ rays and the resulting cation 2a was stable enough to provide a candidate for a novel dosimetry system.

1H and 13C NMR Detection of the Carbocations or Zwitterions from Rhodamine B Base, a Fluoran-Based Black Color Former, Trityl Benzoate, and Methoxy-Substituted Trityl Chlorides in the Presence of Alkali Metal or Alkaline Earth Metal Perchlorates in Acetonitrile Solution

Abstract The cleavage of C–O bonds in two fluoran-based dyes by the addition of alkali metal (M+ = Li+, Na+) and alkaline earth metal (M2+ = Mg2+, Ba2+) perchlorates in acetonitrile solution was examined by means of UV-visible absorption and 1H and 13C NMR spectroscopy at room temperature. Although the 1H NMR signals of the xanthene part of Rhodamine B base (3′,6′-bis(diethylamino)fluoran) were shifted toward lower fields, those of the isobenzofuran (or the benzoate) part were not shifted much upon the addition of M+ and M2+. The appearance of 13C signals at 163.6 and 162.4 ppm (vs TMS) in the presence of Li+ and Ba2+, respectively, confirmed the formation of the zwitterions from Rhodamine B base. The assignments of the 1H and 13C signals were performed by the HMBC method. The colored zwitterion of a practical black color former, 2′-anilino-6′-dibutylamino-3′-methylspiro[3H-isobenzofuran-1, 9′-(9H)xanthene]-3-one, was produced by the addition of M+ and M2+. The 13C NMR signals at 162.2 and 159.8 ppm in the presence of 2.0 mol dm-3 Mg(ClO4)2 and Ba(ClO4)2, respectively, gave conclusive evidence of the formation of the sp2-hybrid carbon center for the black color former. The interaction between the metal ions and the zwitterions from the fluoran-based dyes decreased as Mg2+ > Ba2+ > Li+ > Na+. The 1 : 1 complex formation constants with the metal ions for both dyes were evaluated based on the UV-visible absorption data. The smaller formation constants of the black color former, compared with those of Rhodamine B base, indicate some more difficulty in the cleavage of the γ-lactone ring, which is probably based on the asymmetric structure of the compound, i.e, only a single dibutylamono-group at the 3′- and 6′-positions. The evidence for the formation of both the trityl cation and the benzoate ion was obtained by the 1H NMR signals from trityl benzoate in the presence of Mg(ClO4)2 in CD3CN containing a small amount of CF3SO3D. The C–Cl bond cleavage of 4-methoxy, 4,4′-dimethoxy, and 4,4′,4′′-trimethoxytrityl chlorides, through the chemical interaction between Ba2+ and Cl- in acetonitrile soluition, was justified by our 13C NMR results.

ChemInform Abstract: Color Intensity Control in Polymers Using Triarylmethane Leuconitriles as Color Formers.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Color intensity control in polymers using triarylmethane leuconitriles as color formers

Several triarylmethane leuconitriles have been synthesized. Color formation rates of triarylmethane dyes from corresponding leuconitriles have been compared in various media. Routes to color-on-demand processes are discussed.