Functional dye

M. Okawara, N. Kuroki, and T. Kitao, Kinousei-Sikiso no Kagaku (The Chemisty of Functional Dyes), CMC, Tokyo, 1981. 

Functional dyes (1) of many types are important photochemical sensitizers for oxidation, polymerization, (polymer) degradation, isomerization, and photodynamic therapy. Often, dye stmctures from several classes of materials can fulfiH a similar technological need, and reviewing several dye stmctures... 

M. Kubota et al., Chemistry of Functional Dyes, p. 223, Mita Press, Tokyo (1989). 

The first chapter of the book deals with leuco-spiropyrans and related spiro compounds, which constitute one of the classes of leuco compounds not of the redox type. Such materials are photochromic, and are of major technical importance. The author, Hiroyuki Nakazumi of the Department of Applied Chemistry at the University of Osaka Prefecture, is well known for his researches in functional dye chemistry, particularly photochromic materials, and he provides a very useful update of the field, covering mechanisms, synthesis, spectra and applications, together with a useful section on approaches to near-infrared absorbing photochromic dyes. 

Another noted and prolific Japanese author in the field of functional dyes, Masaru Matsuoka of the Laboratory of Materials Science, Kyoto Women s University, has written the second chapter, dealing with leuco-quinone dyes. These are the traditional redox leuco systems employed for so many years in the vat dyeing industry, and this chapter is an invaluable review of the chemistry of these systems, drawing on recent mechanistic and structural investigations. Applications considered include not only textile dyeing, but also other more specialized areas, such as hair dyeing, color formers, and photoimaging materials. 

Apart from recapture of the injected electrons by the oxidized dye, there are additional loss channels in dye-sensitized solar cells, which involve reduction of triiodide ions in the electrolyte, resulting in dark currents. The Ti02 layer is an interconnected network of nanoparticles with a porous structure. The functionalized dyes penetrate through the porous network and adsorb over Ti02 the surface. However, if the pore size is too small for the dye to penetrate, that part of the surface may still be exposed to the redox mediator whose size is smaller than the dye. Under these circumstances, the redox mediator can collect the injected electron from the Ti02 conduction band, resulting in a dark current (Equation (6)), which can be measured from intensity-modulated experiments and the dark current of the photovoltaic cell. Such dark currents reduce the maximum cell voltage obtainable, and thereby the total efficiency. 

Functional chemicals, 20 712 Functional dyes, anthraquinone, 9 338-341 Functional failures, 15 476 Functional fluids, alkanolamines from nitro alcohols, 2 119... 

Z. Yoshida, Y. Shirota (eds.), Chemistry of Functional Dyes, Vol. 2,60-67, Mita Press Tokyo, 1993. 

Rurack K, Bricks JL (2001) Towards simple and efficient molecular reporters combining electron transfer and charge transfer in functional dyes of donor-acceptor-spacer-donor constitution. Arkivoc xi 31 10... 

In this section, we present the most important molecular families that have been designed by various groups in order to fulfill these requirements. We will group the materials in different classes by symmetry according to their molecular core. A variety of functional dyes have been linked to each of the cores, the properties and applications of which will be discussed in Section IV. 

Few groups of chromophores exhibit absorbance or fluorescence activity due to electronic transitions in the NIR region. Furthermore, very few dyes are commercially available that could be used in probe applications. The limited commercial availability of NIR-absorbing fluorophores, especially functionalized dyes, is probably the major obstacle in the further development of NIR OFCD. However, the synthesis of several NIR dyes has been reported 39 3 and has been applied successfully in NIR... 

Compound 322 is a functional dye that decomposes to methylene blue in biological systems, and it is used in diagnostics. The thiourea analogues 323 and 324 were synthesized in the hope they would be more stable than 322 and cause less background noise, but this was unfortunately not the case <1996BCJ1423>. 

Santra S, Dutta D, Moudgil BM (2005) Functional dye-doped silica nanoparticles for bioimaging, diagnostics and therapeutics. Food Bioprod Process 83 136-140... 

Functional dyes - p YES, SENSITIZING] (Vol 8) -from anthraqumones [DYES, ANTHRAQUINONE] (Vol 8)... 

Spectral sensitizing dyes are considered functional dyes to distinguish them from conventional colorants. The absorption of radiation by a functional dye causes some additional function(s) to occur, and in many... 

Functional dyes of many types are important photochemical sensitizers for chemical reactions involving oxidation, polymerization, (polymer) degradation. isomerization, and photodynamic therapy. Often, dye structures from several classes or materials can fulfill a similar technological need, particularly for laboratory or small-scale reactions where production efficiency may be of secondary importance. Commercial photochemical technology, however, is more selective and requires photochemical efficiency, ease of product separation, and lack of unwanted side reactions to an extent similar to that required by imaging processes. In addition, reusability of the spectral sensitizer is also preferred in commercial photochemical reactions. 

T Nagamura, M Miura, H Fugita, H Sakaguchi, T Sonoda, H Kobayashi, D Mat-sunaga. Third International Symposium Functional Dyes, P 32. Santa Cruz, CA, 1995. 

During the last decade, the phenomenal rise in high-tech industries has fuelled the need for novel high-tech (functional) dyes having special properties. These hi-tech applications can bear higher costs than traditional dye applications, and this has facilitated the evaluation and use of more esoteric dyes (see Chapter 6). 

The salt load and discoloration of wastewater from dyeworks using reactive dyes often attract criticism on environmental grounds. With mono functional dyes, the fixation yield in exhaustion dyeing processes is in the region of 60 %. 

Functional dyes may be classified in several ways. Here, they are discussed according to their application. However, before doing this, it is pertinent to consider briefly the interactions of functional dyes with various agents. This enables a particular phenomena to be associated with each application. 

Functional dyes are designed to interact with electromagnetic radiation, pH, electricity, heat, pressure and even frictional forces. Each of these interactions is discussed, beginning with the most important interaction, that with electromagnetic radiation. 

Electromagnetic Radiation. Functional dyes interact with electromagnetic radiation in the near-UV (300-400 nm), visible (400-700 nm), and near-IR (700-1500 nm) to produce a variety of effects required for hi-tech applications. The more important effects are described briefly, including their main applications. 

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