Color Photography

Kapecki, Jon; Rodgers, James

doi:10.1002/0471238961.0315121511011605.a01

Cited by 3 publications

(3 citation statements)

References 26 publications

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“…Modern color photography has been based mostly on azomethine dyes, which are formed during processing by reaction between coated dye precursors and derivatives of p -phyenlenediamine (PPD) (Scheme ). , As such, these dyes have become the subject of recent experimental, − and theoretical , investigations, aimed at understanding their spectral and photophysical properties.…”

Section: Introductionmentioning

confidence: 99%

Energy Transfer to the Low-Energy Triplet States of 1,3-Dicarbonylazomethine Dyes: The Role of Unique Geometries and Nonadiabatic Behavior

Abu-Hasanayn

Herkstroeter

2001

J. Phys. Chem. A

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The observed kinetics of energy transfer to PhCO-(CdNAr)-CONHPh (1), PhCO-(CdNAr)-COPh (2), and PhCONH-(CdNAr)-CONHPh (3) (Ar ) p-NMe 2 C 6 H 4 ) is consistent with formation of two triplet states for each dye: T 1 and T 2 . A Balzani analysis of the data observed for 1 affords triplet energies of 23.4 ( 1.6 and 38.5 ( 1.7 kcal/mol for T 1 and T 2 , respectively, and requires that T 1 be formed in reactions having substantial nonadiabatic character. A similar result is found for 2. For 3, T 1 and T 2 are estimated at 25.0 and 38.5 kcal/mol, respectively, but formation of 3-T 1 is found to be largely adiabatic. To rationalize these observations, the dyes have been studied by DFT methods (B3LYP/6-31G*). In the ground state (1-S 0 ) 1 is computed to have a geometry in which the azomethine double bond is coplanar with the anilide fragment but is perpendicular to the carbonyl of the ketone. Similarly, 2-S 0 is calculated to have a twisted 1,3-dicarbonyl arrangement. 3-S 0 , on the other hand, exhibits an intramolecular H-bond between the proton of one anilide and the carbonyl of another, and has a large degree of planarity in the 1,3-dicarbonyl moiety. For all compounds, the lowest triplet state (T 1 ) is calculated to have a geometry in which the azomethine bond is twisted by 70°-80°relative to the ground state, and to have a near-planar arrangement between the azomethine and the two carbonyl groups. The calculated lowest triplet energies are (in kcal/mol): 23.0 and 27.5 for two isomers of 1, 25.2 for 2, and 23.4 for 3. The large geometrical differences between the ground and the lowest triplet states are proposed to provide an efficient mechanism for triplet state stabilization, and to stand at the origin of the observed nonadiabatic energy transfer in 1 and 2. The presence of planarized equilibrium concentrations of 3 due to intramolecular H-bonding can explain the greater rates of energy transfer to 3 compared to 1 and 2.

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Section: Introductionmentioning

confidence: 99%

Energy Transfer to the Low-Energy Triplet States of 1,3-Dicarbonylazomethine Dyes: The Role of Unique Geometries and Nonadiabatic Behavior

Abu-Hasanayn

Herkstroeter

2001

J. Phys. Chem. A

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“…Metal chelate solutions are ubiquitous. , For example, iron chelate solutions are used in photography, gas treating, − and plant and human , nutrition. Chelate solutions of calcium, manganese, zinc, and copper, among others, are also used as micronutrients .…”

Section: Introductionmentioning

confidence: 99%

Pure Metal Chelate Solutions by Ion Exchange

George

Chiang

Wilson

2008

Ind. Eng. Chem. Res.

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Aqueous solutions of the industrially important metal chelate ferric N-(2-hydroxyethyl)ethylenediamine-N,N′,N′triacetate (FeHEDTA) have been made by adsorbing an iron salt (nitrate or sulfate) on Dowex MSC-1 cationexchange resin (Na form), flushing out the sodium salt, and eluting with Na 3 HEDTA. The resulting eluate contained FeHEDTA with iron concentrations approaching 2% that were free from sodium salts. Achieving industrially useful iron concentrations (>4.5%) required countercurrent ion exchange using an ISEP system. Careful manipulation of pH was required to prevent plugging due to precipitated iron oxide/hydroxide.

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“…Conventional silver halide photographic systems − are “wet-developed”. That is, some of the chromogenic chemical reagents are supplied externally via developing baths.…”

Section: Introductionmentioning

confidence: 99%

Polymers for Photothermography: Controlled Thermal Release of Color Photographic Developer from Substituted Polystyrene Derivatives

et al. 2006

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A series of functionalized styrenic polymers were synthesized that were designed to release a low molar mass compound, a color photographic developer (a substituted phenylenediamine), when heated. The developer moieties were covalently bound via special protecting groups (“switches”) that were stable at ambient temperature but decomposed to release the developer above 100 °C. In one series, the protecting group consisted of benzylic carbamates, designed to release via a cationic mechanism. In a second series, the protecting groups comprised ethylene linkages set up for 1,2-elimination, and release occurred via an anionic mechanism. Waterborne formulations of the title polymers suitable for coating were prepared via milling, evaporative dispersion, or emulsion polymerization. The polymers were incorporated into silver halide-based photothermographic media, which were capable of forming color images after appropriate exposure and heat treatment, indicating successful controlled release of the developer. This system may be applicable to other controlled-release applications in which a bound compound is to be released when the material is heated.

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Color Photography

Cited by 3 publications

References 26 publications

Energy Transfer to the Low-Energy Triplet States of 1,3-Dicarbonylazomethine Dyes: The Role of Unique Geometries and Nonadiabatic Behavior

Energy Transfer to the Low-Energy Triplet States of 1,3-Dicarbonylazomethine Dyes: The Role of Unique Geometries and Nonadiabatic Behavior

Pure Metal Chelate Solutions by Ion Exchange

Polymers for Photothermography: Controlled Thermal Release of Color Photographic Developer from Substituted Polystyrene Derivatives

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