Color Formers Research Articles

Novel Color Formers Having a Phenothiazine Moiety.

Novel Color Formers Having a Phenothiazine Moiety.

X-ray crystal structure analysis and atomic charges of color former and developer: 4 colored formers

A phthalide ring (benzene+γ-lactone ring) of a colorless fluoran color former is cleaved by adding the electrophilic H+. This ring becomes a benzene ring D and a carboxyl group as a colored form, and one ring of the xanthene ring skeleton performs a quinonoid form (colored form). The crystal and molecular structures of three colored forms of 2-anilino-3-methyl-6-(N-cyclohexyl-N-methylamino)-9-(o-carboxyphenyl)xanthene C34H33N2O3+·Cl− (1), 2-o-chloroanilino-6-dibutylanilino-9-(o-carboxyphenyl)xanthene C34H34N2O3Cl+·Cl− (2) and 2-anilino-6-(N-ethyl-N-p-tolyl)amino-9-(o-carboxyphenyl)xanthene C36H30N2O3+·C2H6·Cl− (3) complexes were determined by single-crystal X-ray diffraction analysis. The xanthene rings of colored forms 1–3 have coplanar geometry compared with colorless forms. The benzene rings D make small angles with the xanthene ring skeleton so that the colorless forms were almost perpendicular. The C⋯O contacts between the cleaved C(sp3) spirocarbon C6 and two oxygens of the carboxyl group have 2.600(7)–2.842(7)Å. The π electron density migration occurred from the auxochrome HCl attached to the phthalide ring to the xanthene ring. Atomic net charges of the base nitrogen N1 of side chains R1 and R2 indicate positive value and the charges toward N1 to C6 also indicate the alternative system. The anions Cl− of 1–3 have strong N2–H⋯Cl contacts with the base atom N2 of R5 side chains.

Influence of metal quinolinecarboxylates on the image-stability of colorants for information recording systems

Metal complexes of carboxylic acids were prepared, and the protecting effect of these compounds towards the photofading of colour materials derived from colour formers was examined on cellulose. It was proposed that nickel or zinc salts of 8-hydroxyquinoline-2-carboxylic acid and its derivatives can be applied as effective stabilisers against the photofading of indicator dyes in heat- (or pressure-) sensitive recording systems. These metal carboxylates were also found to be very useful for stabilising the coloured form of spironaphthoxazine.

Reversibly thermochromic systems based on pH-sensitive functional dyes

Composites formulated from pH-sensitive colour formers mixed with fatty acid co-solvents and acidic developers have been prepared and their thermochromic properties investigated. Possible explanations for the thermochromic effect have been considered and evidence is presented in support of a mechanism based on phase changes occurring within the compositions during heating and cooling.

13C NMR and Electronic Absorption Spectroscopic Studies on the Equilibrium between the Colorless Lactone and the Colored Zwitterion Forms of a Fluoran-Based Black Color Former

Abstract The equilibrium between the colorless lactone (L) and the colored zwitterion (Z) forms of the fluoran compound 1, which has been widely used as a typical black color former in data-recording systems, has been studied by 13C NMR and electronic absorption spectroscopies. Fluoran 1 showed no visible absorption in aprotic solvents, while a black color appeared in phenolic solvents. The 13C NMR and signal of the spiro carbon of 1 in CDCl3 appeared at 84.2 ppm, indicating that 1 exists substantially as L in aprotic solvents. In phenol d6 at 50 °C, the signal of the spiro carbon in 1 shifted to a lower magnetic field and appeared in the sp2-hybridization region (δ = 162.7), suggesting that in phenol-d6 a cleavage of the C(spiro)–O bond in the lactone ring occurs and that the ring-opened Z form is produced. The equilibrium between L and Z depended strongly on the temperature and solvents. The high temperature and inhibition of the solute (1)–solvent interaction by steric hindrance, self-association and intramolecular chelation of the solvent shifted the L–Z equilibrium toward L. The thermodynamic parameters for the equilibrium reaction in phenolic solvents were also estimated.

X-ray crystal structure analysis and atomic charges of color former and developer: 3. Color formers

The crystal and molecular structures of four color formers of 2′-amino-6′-dibutylamino-3′-methylspiro[isobenzofuran-1(3H),9′[9H]xanthen]-3-one C 34H 32N 2O 3 ( 1), 2-anilino-3′-methyl-6′-N-ethyl-N-(4-methylphenyl)aminospiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3-one C 36H 30N 2O 3 ( 2), 2′-anilino-3′-methyl-6′-dibutylaminospiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3-one C 31H 28N 2O 3 ( 3) and 2′( o-chloroanilino)-6′-di-n-butylaminospiro[isobenzofuran-1(3H),(9′-[9H]xanthene]-3-one C 35H 35N 2O 3Cl ( 4) have been determined by single-crystal X-ray diffraction analysis. Atom–atom nonbonded potential energy calculations and semiempirical quantum chemical calculations have been performed. The xanthene rings of 1 to 4 are slightly bent and the phthalide rings are planar. The phthalide ring moieties are almost perpendicular (88.7(4)–89.9(1)°) to the xanthene rings. The bond lengths C6–O2 are apparently extended from the normal C(sp 3)–O (lactone) length. Atomic net charges around spirocarbon C6 and toward N1 to C6 indicate a weak alternating system in colorless form. As the xanthene ring has a planar geometry, π electron density migration will easily occur from the auxochromes attached to the phthalide ring to the xanthene ring by introducing H + at the C6 position. © 1997 Elsevier Science B.V.

Design of Diphenylether Diazonium Salt and Application to Dual Color Direct Thermal Recording.

We have designed and synthesized diphenylether diazonium salts as red color formers for a black-red dual color direct thermal recording system. The diphenylether diazonium salts obtained form red color via a coupling reaction with Naphthol-AS or yellow color via a coupling reaction with Naphthol-ASI4G. The color forming abilities of papers coated with the mixture of coupler, organic base, thermo-sensitizer and microcapsule incorporating the derivatives were examined. The derivative having normal butyl chain could be encapsulated in high amounts and formed vivid red color. Combined with another black color-forming diazonium salt, black-red dual color direct thermal recording was achieved.

X-ray crystal structure analysis and atomic charges of color former and developer: 2. Color formers

The crystal and molecular structures of 2′-amino-6′-dibutylamino-3′-methylspiro[isobenzofuran-1(3 H), 9′[9 H]xanthen]-3-one ( 1), 2′-amino-6′-( N-cyclohexyl- N-methylamino)-3′-methylspiro[isobenzofuran-1(3 H), 9′[9 H]xanthen]-3-one ( 2) and 2′-(2-chlorophenyl)amino-6′-dibutylaminospiro[isobenzofuran-1(3 H), 9′[9 H]xanthen-3-one ( 3) have been determined by single-crystal X-ray diffraction analysis. Atom-atom non-bonded potential energy and semiempirical quantum chemical calculations have been performed. The xanthene rings of 1 to 3 are slightly bent and the phthalide rings are planar. The phthalide ring moieties are almost perpendicular (88.9(1)–93.5(5)°) to the xanthene rings. The bond lengths C(6)O(2) are apparently extended from the normal C(sp 3O (lactone) length. The temperature factors for one butyl group C(32)C(35)) of 1 increase gradually toward the terminal carbon. The temperature factors for C(30)C(33) of 2 indicate large vibrations and these are reflected in short bond lengths. Two butyl groups of 3 are disordered and these CC bond lengths are short and long alternately. Atomic net charges around spirocarbon C(6) and toward N(1) to C(6) indicate the weak alternative system in the colorless form. As the xanthene ring has a planar geometry, the π electron density migration will easily occur from the auxochromes attached to the phthalide ring to the xanthene ring.

X-ray crystal structure analysis and atomic charges of color former and developer: 2. Color formers

The crystal and molecular structures of 2′-amino-6′-dibutylamino-3′-methylspiro[isobenzofuran-1(3 H), 9′[9 H]xanthen]-3-one (1), 2′-amino-6′-( N-cyclohexyl- N-methylamino)-3′-methylspiro[isobenzofuran-1(3 H), 9′[9 H]xanthen]-3-one (2) and 2′-(2-chlorophenyl)amino-6′-dibutylaminospiro[isobenzofuran-1(3 H), 9′[9 H]xanthen-3-one (3) have been determined by single-crystal X-ray diffraction analysis. Atom-atom non-bonded potential energy and semiempirical quantum chemical calculations have been performed. The xanthene rings of 1 to 3 are slightly bent and the phthalide rings are planar. The phthalide ring moieties are almost perpendicular (88.9(1)−93.5(5)°) to the xanthene rings. The bond lengths C(6)O(2) are apparently extended from the normal C(sp 3)O (lactone) length. The temperature factors for one butyl group C(32)C(35)) of 1 increase gradually toward the terminal carbon. The temperature factors for C(30)C(33) of 2 indicate large vibrations and these are reflected in short bond lengths. Two butyl groups of 3 are disordered and these CC bond lengths are short and long alternately. Atomic net charges around spirocarbon C(6) and toward N(1) to C(6) indicate the weak alternative system in the colorless form. As the xanthene ring has a planar geometry, the π electron density migration will easily occur from the auxochromes attached to the phthalide ring to the xanthene ring.

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 novel approach for improving the light fastness of crystal violet lactone

Colour formers are important as functional dyes for imaging and data recording systems. Metal complexes of substituted arylsulphonic acids or arylcarboxylic acids have been synthesised to prolong the life of coloured species derived from crystal violet lactone. The suppressing effect of these compounds towards photofading was investigated on cellulose. It was found that zinc and nickel salts of 2,6‐dihydroxybenzoic acid and its derivatives can be applied as effective stabilisers against the fading of crystal violet lactone. The protecting effect of phenyl esters against fading was also examined.

Photostabilisation of colour formers for heat‐sensitive recording systems: Effect of counter‐ions on the photofading of fluoran dyes

AbstractFluorans are given considerable attention as functional dyes for heat‐and/or pressure‐sensitive recording media. Numerous potential metal complexes were synthesised to prolong the life of coloured species. The protecting effect of these compounds against the photofading was examined on cellulose. It was found that the zinc or nickel salts of 3,5‐dihydroxy‐2‐naphthoic acid and its derivatives can be applied as effective stabilisers against the fading of fluoran dyes.

Naphthoquinone methide-type near-IR colour formers: their synthesis and oxidation properties

New colourless naphthoquinone methide-type near-IR colour formers 1 have been synthesized, which immediately exhibit intense absorption in the near-IR region upon oxidation by p-benzoquinone. The colour development has been investigated using the stopped-flow technique. In the presence of a basic catalyst, NEt3, oxidation of 1 gave the corresponding carbonyl cyanide derivatives 3 as the major products.

Synthesis and colour development properties of indoaniline-type near-IR colour formers

New indoaniline-type near-IR colour formers have been synthesized as stable compounds, which on metal chelate complexation–oxidation, immediately exhibit intense absorption in the near-IR region. This colour development has been investigated using the stopped-flow technique.

Synthesis and properties of 6-substituted quinoline-5,8-dione colour formers

New 6-substituted quinoline-5,8-dione colour formers which immediately produce intense absorption bands in the visible and near-IR regions on simultaneous metal chelate complexation–oxidation processes have been synthesized. The rapid spectral changes which they undergo have been investigated by using the stopped-flow technique.

Syntheses of Naphthoquinone Methide-type Near-IR Color Formers

Abstract New naphthoquinone methide-type near-IR color formers have been synthesized, which immediately exhibited intense absorption in the near-IR region on oxidation. The color development has been investigated using the stopped-flow technique.

Syntheses of pyrido[2,3-a]phenothiazine-type near-IR colour formers

New pyrido[2,3-a]phenothiazine-type near-IR colour formers have been synthesized, which on metal chelate complexation–oxidation, immediately exhibit intense absorption in the near-IR region. This colour development has been investigated using the stopped-flow technique.

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.

情報記録用色素の化学と新展開

Recent trends in the chemistry and applications of functional dye materials for information recording are reviewed. Colorants for hard copy systems and optical recording media are the most important applications in this field. Molecular design of dye chromophores can be conducted by molecular orbital method to estimate their absorption spectra, dipole moment, transition moment, and so on. And then, material design induced from physical properties of dyes in molecular level can be attained. On the other hand, material design evaluating the macroscopic properties such as conductivity, thermal and photochromic properties of dye aggregates or crystals can not be achieved yet. Empirical and experimental approaches to correlate the macroscopic properties of dye aggregates with chemical structure are anticipated to advance the material science of dye chromophores. The chemistry of color former, cycolor system, decolorizable toner, radical photography, dry type photography, diazo materials, OPC and related chemicals are summarized. Dyes for D2 T2, optical recording media for DRAW, photochromic dye and dye for PHB are also presented.

Photostabilisation of colorants for imaging and data recording systems: effect of metal carboxylates on the lightfastness of colour formers

Metal complexes of hydroxycarboxylic acids or dicarboxylic acids were prepared and the protecting effect of these compounds towards the photofading of colour materials derived from colour formers was examined on cellulose. It is proposed that nickel or zinc salts of 1-hydroxy-2-naphthoic acid and its derivatives can be applied as effective stabilisers against the photofading of indicator dyes in pressure- (or heat-)sensitive recording systems. These metal carboxylates were also found to improve the image stability of the indicator dyes.