Indicator dyes phthalocyanine

Dyes and Pigments. Several thousand metric tons of metallated or metal coordinated phthalocyanine dyes (10) are sold annually in the United States. The partially oxidized metallated phthalocyanine dyes are good conductors and are called molecular metals (see Semiconductors Phthalocyanine compounds Colorants forplastics). Azo dyes (qv) are also often metallated. The basic unit for a 2,2 -azobisphenol dye is shown as stmcture (11). Sulfonic acid groups are used to provide solubiHty, and a wide variety of other substituents influence color and stabiHty. Such complexes have also found appHcations as analytical indicators, pigments (qv), and paint additives. 

Custom modifications have previously been developed whereby a non-fluorescent chromophore can be attached to the DNA sequence to provide a strong SE(R)RS signature which is indicative of the DNA sequence present. This has been done previously using DABCYL, phthalocyanines and black hole quenchers (BHQs) as well as specifically designed simple azo dyes which contain moieties to aid in their binding ability to metal surfaces such as the benzotriazole motif which has been shown to be very effective at complexing onto silver nanoparticles [12, 13, 40, 41]. 

With regard to cellulosic fibres, the simplest test for the dyes which will probably be present, ignoring unlikely ones such as acid or basic dyes, is to boil for 1 to 2 minutes with a 5 per cent caustic soda solution. If a considerable quantity of colour is stripped a substantive dye is indicated, and it will probably be an azo dye if the colour of the fresh sample is destroyed by boiling for 2 minutes with Formosul G. If, on the other hand, very little or no dye is stripped, the inference is that the material has been dyed with a sulphur, vat, or reactive dye. When boiled for 1 to 2 minutes with Formosul G and a few drops of sodium hydroxide solution, azoic or reactive dyes are virtually stripped. They can, however, be distinguished because only reactive dyes and certain phthalocyanine derivatives, usually recognizable by their distinctive colour, will withstand the following treatment (Giles et. al., J.S.D.C., 1962, 78, 126) ... 

Nimmo et measured the Raman scattering of copper phthalocyanine in pressed silver, KBr, Cu, and A1 disks. This is a dye producing intense signals at concentrations as low as 10 M The ratio of intensities measured for the four substrates was about 10 < 1 1 2, respectively, which indicates (very) small enhancements for silver. Note, however, that the authors did not show that such silver disks exhibit SERS for normal Raman scatterers. 

Certain materials, such as many phthalocyanines [45], can only be deposited during each upstroke (Z-type deposition) and others only during each insertion (X-type). The type of deposition followed by a particular material affects the properties of the resulting LB films due to symmetry restrictions for second-order physical effects such as piezoelectricity or optical second-harmonic generation. The bilayer unit (equivalent to the unit cell in a crystal) is symmetric for Y-type deposition but non centric for Z- and X-type modes, as indicated in Figure 12.12. Unfortunately, several researchers have found that Z- and X-mode multilayers are often temporally unstable, although the zwitterionic dyes of Ashwell prove to be one of the exceptions [46]. 

The term probe is normally used as a synonym of label. Thus, in contrast to labels, probes respond to their microenvironment or to a chemical species. Those probes responding to a chemical species such as oxygen, an ion, or to pH are also referred to as indicators. In this article, both terms will be used indistinctly. Different classes of fluorescent labels are available. Low molecular weight dyes include xan-thene (rhodamines, fluoresceins), cyanine, coumar-ins, sulfonated pyrenes, and metal phthalocyanine compounds, while high molecular weight labels include phycobiliproteins and other luminescent proteins. 

Two basic polyelectrolytes were chosen for film deposition, i.e. poly(alylamine) hydrochloride (PAA) and poly(sterenesulfonate) sodium salt (PSS) both purchased from Aldrich. Organic indicators, namely, cyclo-tetrachromotropylene tetra-sulfonic sodium salt (CTCT) (synthesised at Sheffield University [19]), Copper Phthalocyanine tetra-sulfonic sodium salt (CuPc), Thymol Blue (TB) sodium salts (purchased from Aldrich) were embedded into the polymer matrix. Chemical formula of all compounds used are shown in Fig. 1. Aqueous solutions of 1 mg/ml concentration of the above polyions and organic dyes were used for film deposition. 

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