Solubilizing groups

Surface activity is not limited to aqueous systems, however. AH of the combiaations of aqueous and nonaqueous phases are known to occur, but because water is present as the solvent phase in the overwhelming proportion of commercially important surfactant systems, its presence is assumed in much of the common terminology of industry. Thus, the water-soluble amphipathic groups are often referred to as solubilizing groups. 

Carboxylate, sulfonate, sulfate, and phosphate ate the polar, solubilizing groups found in most anionic surfactants. In dilute solutions of soft water, these groups ate combined with a 12—15 carbon chain hydrophobe for best surfactant properties. In neutral or acidic media, or in the presence of heavy-metal salts, eg, Ca, the carboxylate group loses most of its solubilizing power. 

Fast Color Salts. In order to simplify the work of the dyer, diazonium salts, in the form of stable dry powders, were introduced under the name of fast color salts. When dissolved in water they react like ordinary diazo compounds. These diazonium salts, derived from amines, free from solubilizing groups, are prepared by the usual method and are salted out from the solutions as the sulfates, the metallic double salts, or the aromatic sulfonates. The isolated diazonium salt is sold in admixture with anhydrous salts such as sodium sulfate or magnesium sulfate. 

Yellow Couplers. The most important classes of yeHow dye-forming couplers are derived from P-ketocarboxamides, speciftcaHy the benzoyl acetanilides (6) (66) and the pi val oyl a ceta n il i des (7) (67). Substituents Y and Z can be used to attach baHasting or solubilization groups as weH as to alter the reactivity of the coupler and the hue of the resulting dyes. Typical coupling-off groups (X) cited in the Hterature are also shown. 

Solvent Dyes. These water-iasoluble dyes ate devoid of polar solubilizing groups such as sulfonic acid, catboxyHc acid, or quaternary ammonium. They ate used for coloring plastics, gasoline, oUs, and waxes. The dyes ate ptedomiaandy azo and anthraquiaone, but phthalocyaniaes and ttiaryHnethane dyes ate also used. 

Several soluble precursor approaches were reported to produce high-molecular-weight soluble precursors, which could be later reacted to remove the solubilizing groups. The introduction of bulky substitutions can reduce crystallinities or even suppress crystallization of a polymer, thereby improving its solubility substantially. Thus, the incorporation of removable substituents provides a strategy for... 

Fullerene derivative 34 substituted with two long alkyl chains (solubilizing groups) and a carboxylic function was used as peripheral subunit for the constructions of the dendrons (Fig. 14). 

Sensitive dienol ether functionality in the diene carboxylate was shown to be compatible with the conditions of the aqueous Diels-Alder reaction (Eq. 12.26).84 The dienes in the Diels-Alder reactions can also bear other water-solubilizing groups such as the sodium salt of phosphoric acid and dienyl ammonium chloride (Eq. 12.27).85 The hydrophilic acid functionality can also be located at the dienophile.86... 

A series of zinc(II) phthalocyanines with other sorts of solubilizing groups in exo or endo positions (carboxyalkyl, carboxyalkoxy, amino acid) has been synthesized and subjected to preliminary in vitro assays.257 Interestingly, the seryl derivative zinc(II) 2,9,16,23-tetrakis(l-car-boxy-2-hydroxyethylaminocarbonyl)phthalocyanine proved to be cytotoxic (i.e., toxic in the dark) which is not so commonly observed with macrocyclic systems. 

Naturally occurring monoterpene alcohols were heated in water without prior deriva-tization with typical biological water-solubilizing groups such as phosphates or glyco-sidic units. Biomimetic reactions that normally would be acid-catalyzed, proceeded on the underivatized compounds in the absence of added acidulant. Cooling of the mixtures rendered the products insoluble, readily isolable and the aqueous phase did not require neutralization before workup. 

Porphyrazines with alkyl or aryl substituents are considerably more soluble than their unsubstituted counterparts (Section III. A). Consequently, various pz isomers with alkyl and aryl substituents, for example, symmetrical M[pz(A4)] and unsym-metrical M[pz(A3B)], have been reported. In particular, the symmetrical species M[pz( A4)] have been used both as vehicles to study the fundamental physical properties of metalated porphyrazines (52) as well as to make double decker or sandwich porphyrazines, cofacial dimers linked with lanthanide metal ions (34), while the unsymmetrical species M[pz(A3B)] have utilized the alkyl-aryl substituents as solubilizing groups and have been applied to all areas of pz chemistry. 

It is important for metal complex compounds to be free from solubilizing groups in order to provide the necessary pigment characteristics. 

A basic nitrogen (although not a prerequisite) is often associated with hERG activity therefore, alternative solubilizing groups should be considered. 

In this chapter we will cover the existing literature on fullerenes for PDT, summarize results from our laboratory and outline future possibilities concerning applications of fullerenes as PS for PDT. Figure 4.1 gives a schematic outline of the PDT applications that have been reported for fullerenes either pristine or functionalized with various solubilizing groups. 

Lavastre s approach is valid, but the use of (a) less reactive brominated arenes and (b) the obvious lack of solubilizing groups restricts the value of this approach. Perhaps all of the 96 polymers would have to be made in a conventional approach and compared to the polymers obtained by the high-through-put method to draw further conclusions. In addition, the fluorescence was measured in situ, in a THF/diisopropylamine mixture in the presence of the Pd-Cu catalyst. That approach may have an intrinsic problem too, because it is known that PAEs are solvatochromic, and as a consequence, the obtained fluorescence data might be biased. However, with some tweaking this is a powerful method to obtain a cornucopia of different structures quickly and without too much synthetic effort, if the monomers are easily available. 

The sulfuric acid esters as compared to the sulfurous esters are the most widely used. In nature they appear as solubilizing groups in... 

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