Chromophores materials

S2) investigating single crystals 3) considering doped chromophore materials with (inert) host crystals... 

When utilized in the vision process, the Rhodonine chromophores are formed into a liquid crystalline state on the surface of a substrate, known generically as the protein opsin. It appears that the chromophores are held to the opsin substrate by very weak bonds of the hydrogen bond type. This linkage does not disturb the unique electronic configuration of the chromophoric material. 

Figure 5.3.5-1 The devolution of the properties of candidate chromophoric materials. The shaded area on the right highlights the unique properties of the chromphores of vision. This is the only state in which the functional properties of the chromophores can be determined in the laboratory. The shaded area in the upper left is only shown for completeness and will not be discussed in detail. See text.

The net effect of the spaceframe stmcture used in vision is that the overall absorption spectrum of a multilayer section of chromophore material is considerably broader on a relative basis than that measured for a single monolayer of chromophore. 

Figure 5.3.5-1 The devolution of the properties of candidate chromophoric materials. 26...

Although the synthesis of each chromophore material is to some extent unique (and hence requires individual description which is beyond the scope of this review), most chromophores used for device prototyping involve amine donor moieties. Thus, once a large quantity of aldehyde-terminated amine do-nor/partial bridge material has been synthesized, it can be reacted via Knoeve-nagel condensation with a variety of acceptor groups to form different series of chromophores. The acceptor in Schemes 1-4 is 3-cyano-5,5-dibutyl-2-dicy-anomethylene-4-methyl-2,5-dihydrofuran (which we refer to as the cyanofuran, CF, acceptor). This is synthesized by a literature method [213]. 

A uniform electric field distribution across the sample is extremely important for achieving device quality materials. Unfortunately, real chromophore materials do not always behave as uniform insulator materials. We have already demonstrated that ionic impurities can dramatically reduce the effective electric field felt by chromophores. The presence of spatially and temporally varying nonuniform space charge distributions leads to nonuniform poling fields. The resulting nonuniform chromophore order can lead to light scattering. 

It has been reported that a yellow substance is liberated from crystalline, sweet-potato beta-amylase when the enzyme is subjected to gel filtration on Sephadex at pH 8.8 in the presence of pyrophosphate buffer. The chromophoric material can also be obtained by treating the enzyme with acetic acid, and can readily be reattached. 

Figure 3.109 shows a general scheme combining distinct disciplines in TP photosciences. It demonstrates the interdisciplinary cooperation needed to become an accepted scientific field in both academic and industrial areas. It demonstrates the workflow, starting from basic research including theory, synthesis, and chromophore characterization. Development of TP chromophores, materials needed for TP application, and methods and equipment required in TP photosciences will require interdisplinary work by theoretical scientists, organic chemists, polymer chemists, physical chemists, and physicists. 

Samples. All samples of chromophore materials were obtained from other researchers and used without further pu cation. Sources included Dr. W. A. Feld, Wright State University, Dr. Susan Ermer, Lockheed Martin Co., Dr. Robert Miller, IBM and Dr. Alex Jen, ROI Technology. The sources of each sample will be given when the results are presented. 

A special mention has to be made concerning the PVC-wood composites subjected to accelerated weathering they retained their initial mechanical properties in a higher proportion than the originating polymer [35, 58, 59]. The possible explanation of this behavior may be that the photo-oxidation takes place only at the surface of the composite where wood particles, considered as a chromophore material because of the presence of carbonyl groups, undergo photochemical degradation. Hence, all composite samples exhibited a more intense discoloration than the neat PVC. 

Minato, S., and Werbin, H., 1971, Spectral properties of the chromophoric material associated with the deoxyribonucleic acid photoreactivating enzyme isolated from baker s yeast. Biochemistry 10 4503. 

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