Dye Chemistry Research Articles

Improving Contrast Ratio in Color Filters for AMLCD Devices

ABSTRACTThe widespread use of pigmented color filters in the AMLCD industry has focused attention on their deficiencies, which include marginal film transmittance, significant depolarization and generally poor imaging characteristics for the corresponding imaging resists. These limitations result in diminished color filter contrast and curtailed brightness for the AMLCD device. Incremental color filter contrast improvements have been generated through use of smaller pigment particles which reduce, but do not eliminate, light scattering. As standard pigment synthetic and grind processes give only small color contrast gains, at a cost of protracted pigment manufacture time, another route to more significant gains in color filter contrast is probably necessary. The work herein describes our attempt at defining one viable approach to real improvements in the key color filter responses of reduced depolarization and improved color contrast.Our approach employs colorants prepared from colloidal suspensions of nanosized, mono-dispersed, dense silica spheres to which appropriate red, green and blue dyes are sorbed. Subsequent dispersion of each colorant nanocomposite in carrier polymer and photoimaging chemistry yields the corresponding negative-tone red, green and blue imageable photoresist. The synthesis and use of monodispersed colorant colloids has been described by Giesche and Matijevic for this and other related areas, but their utility is limited to applications not addressing the more advanced color filter requirements mentioned above. To those ends, our work focused on the synthesis, formulation and optical testing of nanocomposite colorant particles ranging from 10–30 nm in size, using dye chemistry which bridges compatibility between both silica nanosphere and carrier polymer, resulting in clear, highly transparent color films. Two independent optical tests comparing the color contrast on nanocomposite red films with coatings of similar transmittance prepared from reference red pigment dispersion provided rationalization that light scattering is significantly reduced in the nanocomposite film, as evidenced by the 3–10 fold increase in the color contrast ratios.

Environmental chemistry of dyes and pigments

Partial table of contents: WASTEWATER TREATMENT METHODS. Carbon Adsorption of Dyes and Selected Intermediates (A. Reife & H. Freeman). Ozonation (M. Matsui). Use of Electrochemical Technology to Remove Color and Other Contaminants from Textile Mill Effluents (A. Wilcox, et al.). The PACT System for Wastewater Treatment (D. Hutton, et al.). WASTE MINIMIZATION/SOURCE REDUCTION. Reduction of Textile Wastewater Using Automatic Process Control, Recycle, and Filtration (J. Porter). Membrane Filtration Techniques in Dyestuff Recovery (J. Elliott). WASTEWATER ANALYSIS. Mass Spectrometry in the Analysis of Dyes in Wastewater (L. Betowski, et al.). REGULATORY ISSUES. U.S. Safety, Health, and Environmental Regulatory Affairs for Dyes and Pigments (H. Smith). Index.

Imaging exocytosis and endocytosis

From the secretion of neurotransmitters via synaptic vesicles to the expulsion of cellular waste via contractile vacuoles, exocytosis and its sequel, endocytosis, are being explored with a variety of new optical tools. Fluorescent markers, especially styryl dyes such as FM1-43 (which reversibly labels endosomal membranes), have been used to follow exo- and endocytic events in many cell types. Even though the development of new dyes is still largely empirical, some theoretical principles have emerged to guide future dye chemistry. Moreover, advances in optical imaging technology that augment conventional fluorescence microscopy are appearing. For example, interference reflection microscopy (which requires no flurophore) and total internal reflection microscopy have recently been used to observe single exocytic events at the contact point between a glass coverslip and the plasma membrane.

Alcian blue. Now you see it, now you don't.

A brief outline of the history and chemistry of the copper pthalocyanin-based Alcian blue dyes highlights the adverse effects of commercial secrecy and entrepreneurial dishonesty on the use of these valuable histochemical and biochemical reagents in the biological sciences. The acquisition of detailed and validated chemical structures required the avoidable expenditure of much time that otherwise would have been spent on new research. The combination of this chemical knowledge with experiments on isolated polyanions, using critical electrolyte concentration (CEC) techniques, established a molecular recognition paradigm of Alcian blue usage in histochemistry. New reagents (Cuprolinic and Cupromeronic blues) were synthesised to investigate and support the hypothesis that Alcian blue did not intercalate with DNA. They were made with the important additional aim of using them in electron microscopy of polynucleotides (in the case of Cuprolinic blue) and non-nucleotide polyanions, such as sulphated proteoglycans in extracellular matrices (in the case of Cupromeronic blue). The cationic groups of Alcian blue are easily removed in very mild conditions, producing insoluble blue pigment in situ (ingrain dying). This reaction underlies its unique capability to stain in repeated cycles, thus greatly amplifying sensitivity of detection of substrates present in very small amounts in tissues and on electrophoretic strips etc.

Industrielle Bedeutung der Vilsmeier-Haack-Reaktion in der Farbstoffchemie

Vilsmeier–Haack Formylation Reaction – Importance in Colour Industry The Vilsmeier-Haack reaction which has been discovered in 1927 is being used in industry to formylate alkylated aromatic amines and related compounds. Roughly 2000 tons of formylation products are yearly produced in the world. Preferably they are used as building blocks in dye chemistry. Many classes of dyes like cyanines, coumarin dyes, merocyanines, cationic dyes, color formers or dyes for non linear optical applications are being obtained from „Vilsmeier”︁ products. Different conditions of the Vilsmeier-Haack reaction and alternative routes for the introduction of a formyl group are discussed in this progress report.

A World of Color: Investigating the Chemistry of Vat Dyes

The study of vat dyes involves an application of oxidation-reduction chemistry. Here this chemistry of vat dyes is thoroughly explored using Inkodye as the group of vat dyes.

The Chemistry of Fabric Reactive Dyes

This article is written for high school chemistry teachers who wish to introduce the activity of tie dyeing to show its application to organic chemistry. It discusses the processes and the chemistry involved in the various steps of tie dyeing fabric with procion MX (dichlorotriazine), a commonly used fabric reactive dye. The preparation of the solutions, the purpose of each chemical, the structural diagrams of several colors of the dye, and the chemical reactions with the fabric are included in the article.

Thirty-five years of studies on the chemistry of polymethine cyanine dyes

Studies on the chemistry of polymethine cyanine dyes carried out since 1958 at the East China University of Science and Technology (formerly the East China University of Chemical Technology) are reviewed. The dyes studied include polymethine cyanine dyes used in photography and dye lasers. Kinetic studies of the formation of polymethine dyes, and the theory of sensitization are also described.

Cyclic Carboxylic Imide Structures as Structure Elements of High Stability. Novel Developments in Perylene Dye Chemistry

Cyclic Carboxylic Imide Structures as Structure Elements of High Stability. Novel Developments in Perylene Dye Chemistry

Robert Hill, 2 April 1899 - 15 March 1991

Robert Hill will always be remembered for his fundamental contributions to the study of photosynthesis, but his originality in the scientific sphere was the reflection of an unusual personality, which will not be so easily remembered without a written record. He was almost invariably known affectionately as Robin, by family, friends and colleagues alike, although his closest friends tended to address him simply as Hill, in the pre-war manner. The scientific outlook was a deep seated part of Robin’s nature, but he was also an artist and craftsman. The different aspects of his life merged into one another with no sharp distinctions. He was trained primarily as a chemist, but in the inter-war years he was one of the pioneers who applied chemical skills and insight in attempts to understand living things, and thus established biochemistry on a sound basis as an independent discipline. His great love was for plants. At the old farm in Barton where he made his home, he grew all the plants needed for his experimental work in the laboratory. For Robin Hill this meant growing any plant with some particular biochemical interest. Among them were the traditional dye plants, such as madder and woad, and he became a well known expert in the chemistry of the natural dyes. Plants and landscapes were the usual subjects of his watercolour sketches. Some of these could be seen hanging in the house, but he was too modest to explain to visitors that he had not only painted the pictures but had also made the pigments himself. He spent the whole of his working life in Cambridge. He had a highly individual lecturing style which could occasionally verge on the histrionic, but his shyness came to dominate. He would stand with his attache case open on the bench in front of him, spectacles cocked on his forehead, and from time to time would duck down, for protection from the audience, as it were. These antics were amusing but distracting, and may partly explain why he never achieved a university appointment. He existed on a series of fellowships until he was eventually rescued by the Agricultural Research Council, and taken on to their external staff in 1943.

Quantitative multicomponent spectral analysis using neural networks.

Recent developments in dye chemistry and modern optics have made simultaneous measurement of multiple intracellular ion species possible1. Analysis of optical spectra from intact tissues is complicated because of the presence of multiple components. Quan­titative descriptions of these components are required to apply these techniques to analyti­cal chemistry and cellular physiology. Ratio methods2 have been applied to many areas of quantitative optical signal measurement because the quantitative data is independent of dye concentration, path length and light source intensity. However, it is known that the ratio method can give erroneous results3 without special attention to the choice of the op­timal wavelengths for these methods. Full spectra carry all the information needed for qualitative and quantitative analysis. Methods like principal component regression (PCR) and partial least-squares (PLS), which have been used for full spectra calibration in most chemometrics literature4,5, or multicomponent stripping for image applications 6,7,8 need heavy computation times to perform their optimization processes.

Some recent advances in kinetic studies in dye chemistry

The importance of kinetic studies in dye chemistry is emphasized. The high pressure liquid chromatographic method, thin layer chromatograph-double scanning and proton NMR technique used to determine the rates of chemical changes are reviewed.

Dyes for Optical Recording

Abstract Dyes for optical recording systems such as laser optical recording systems, laser printing systems, cycolor and related systems, xerography and so on are reviewed. Infrared absorbing (IR) dyes are newly designed for laser optical recording systems such as DRAW and erasable type recording systems. The chemistry of IR dyes developed the new fields in dye chemistry. Many of functionalities in dye chromophores are newly developed for optical recording systems such as PHB and cycolor systems. New technology has developed new dye chemistry and new characteristics of dye chromophores advanced the technology for new optical recording systems.

The technology—science interaction: Walter Reppe and cyclooctatetraene chemistry

This is another paper about science and her powerful companion (technology), to use A. W. Hofmann's colourful phrase. Whereas most papers on the interaction of science and technology deal with the transfer of knowledge from academic science to industrial technology, this paper is about the contribution of an industrial researcher to academic chemistry. The boost Reppe's research gave to the study of aromaticity parallels the impact of the early synthetic dye chemistry on structural organic chemistry. This case study suggests that we cannot draw a clear distinction between ‘pure’ and ‘applied’ chemistry, in the laboratory at least.

Radiation chemistry of cyanine dyes: oxidation and reduction of merocyanine 540

Merocyanine 540 (MC) shows promise as a treatment for certain types of leukemia. It is shown that MC readily undergoes one-electron reduction under pulse radiolytic conditions. The {pi}-radical anion, produced by reduction with hydrated electrons and 2-hydroxypropyl radicals, disproportionates rapidly (k = 1.9 {times} 10{sup 9} M{sup {minus}1}s{sup {minus}1}) under anaerobic conditions but reduces O{sub 2} to superoxide ions (k = 1.6 {times} 10{sup 9} M{sup {minus}1}s{sup {minus}1}) in aerated solution. The dye reacts with trichloromethylperoxyl radicals (k = 9 {times} 10{sup 8} M{sup {minus}1}s{sup {minus}1}) to form several products, one of which is believed to be an adduct formed by addition of CCl{sub 3}OO{sup {sm bullet}} to the bridgehead carbon atom of the benzoxazole subunit. This species decays via first-order kinetics (k = 4.0 {times} 10{sup 3} s{sup {minus}1}) under pulse radiolytic conditions to form cleavage products. A second primary product is believed to arise from addition of CCl{sub 3}O{sub 2}{sup {sm bullet}} to the polymethine chain to form an {alpha}-amino carbon-centered radical capable of reducing O{sub 2} to superoxide ions. Preliminary studies indicate that the breakdown products are cytotoxic and could be important intermediates for the known antiviral activity of MC.

海洋生物色素

海洋生物色素

ChemInform Abstract: A New Chromophoric and Redox‐Responsive Ionophore Containing a Tricyanovinyl Moiety.

AbstractAccording to a reaction well known in the field of dye chemistry, TCNE (I) reacts with anilines (II) to give products (III) which are examined by UV‐VIS and cyclic voltammetry.

The Chemistry and application of dyes

The Chemistry and application of dyes

A highly fluorescent simultaneous azo dye technique for demonstration of nonspecific alkaline phosphatase activity.

We describe a fluorescent histochemical technique for detection of nonspecific alkaline phosphatase (APase) in cells. The technique utilizes standard azo dye chemistry with naphthol AS-MX phosphate as substrate and fast red TR as the diazonium salt. The reaction product is a highly fluorescent red precipitate. Pre-implantation mouse embryos were used to establish optimal fixation and staining protocols and the specificity and sensitivity of the method. Fixation was in 4% paraformaldehyde for 1 hr, as glutaraldehyde induced autofluorescence of the cells. Maximal discriminable staining was detected after 15-20 min in the stain solution. The stain solution itself proved to be non-fluorescent, thus allowing visual observation of the progress of the staining reaction by fluorescence microscopy in its presence. To test the specificity of this fluorescent APase stain, a variety of cell types of known APase reactivity were stained by this protocol. Mouse lymphocytes and STO fibroblasts were negative, whereas F9 teratocarcinoma cells, intestinal epithelial cells, and rat fetal primordial germ cells were all found to be highly positive for APase activity, in agreement with published results on APase localization in these cells.

The chemistry of special dyes for electro‐optical applications

The chemistry of special dyes for electro‐optical applications