Methanes, triaryl

Die Reduktion von Triaryl-carbinolen zu Triaryl-methanen mit 96%iger Ameisensaure wird selten angewendet1 2. So erhalt man z. B. aus Diphenyl-(4-fluor-phenyl)-carbi-nol Diphenyl-(4-jluor-phenyl)-methan (79% d.Th. F 62-63°), als Nebenprodukt ent-steht 4-Diphenylmethyl-phenol (13% d.Th. F 109—111°)3. 

Two different nucleophiles can be used but lower yields of the triaryl methane leuco dyes containing three different rings are obtained. For... 

Diaryl and triaryl benzylic alcohols generally undergo smooth reduction to the corresponding hydrocarbons. Thus, both diphenyl- and triphenylcarbinol quickly give good to excellent yields of the corresponding substituted methanes when... 

Diaryl- and triaryl-methane dyes also fall into this class [(124) is known as Michler s Hydrol Blue] and a number of the heterocyclic derivatives of these dyes are well known. Introduction of a sulfur bridge into Michler s Hydrol Blue (124) results in the dye Thiopyronine (125) which absorbs at 565 nm. The analogous dye with an oxygen bridge, Pyronine, absorbs at 545 nm and that with an —NH— bridge, Acridine Orange, absorbs at 490 nm (B-76MI11201). 

Trimesitylmethane is an example of isomerism and isomerization in ArgZX systems with C3 symmetry. Pioneering studies on related triaryl-methanes provided valuable observations concerning structure and mechanism of stereoisomerization. 39-41) jn particular, an X-ray diffraction study 41> of dimesityl-(2,4,6-trimethoxyphenyl)methane showed that this compound adopts a propeller conformation in the solid state. A similar conformation was found for triphenylmethane in the gas phase by electron diffraction.42) Nmr evidence is also consistent with such a conformation for triarylmethanes in solution. 39-41) jn the following, we shall briefly describe our experience with trimesitylmethane (7). 43)... 

Basic paper, polyacrylonitrile, modified nylon, polyester and inks applied from acidic dyebaths cyanine, hemicyanine, diazahemi-cyanine, diphenylmethane, triaryl-methane, azo, azine, xanthene, acridine, oxazine, and anthraquinone... 

A new type of triaryl phosphine-functionalized imidazolium salt containing cations such as (6) has been prepared. Palladium complexes of (6) generated in situ have been used successfully in Heck-type reactions of aryl halides with acrylates and of 4-bromotoluene with styrene derivatives.34 The first Heck-type reaction of aryl halides with allenes has been reported. 1,3-Double arylations were observed with 3-substituted-l,2-allenyl sulfones, while 1-monoarylation was favoured with 3,3-disubstituted-l,2-allenyl sulfones.35 It has been shown that the a-arylation of methane-sulfonamides (7) may be achieved using palladium catalysis reaction proceeds through the sulfonamide enolates.36 It is also reported that palladium cross-coupling of alkynes with /V - (3 - i odophe n y I an i I i ncs) may lead to the formation of substituted carbazoles.37... 

Basic Blue 22, and C.l. Basic Red 18. The triaryl methane dye C.l. Basic Violet 3 has a mobile cation that produces resonance structures of comparable energy. 

Studies of the dissociation energy of compounds of the hexa-aryl ethane type to triaryl methane and similar radicals have been made in solution. Ziegler and Ewald, for example, measured the heat of dissociation of hexaphenyl ethane from the temperature dependence of the equilibrium constant. I he equilibrium constant was measured using the extinction coefficient. They obtained a value of 10-12 kcal, depending slightly on the solvent used. Other results for this compound are quoted by Szwarc ] ut they lie within these limits. The values for the dissociation in the vapour phase cannot ]>e obtained, and the corrections required may... 

Basic (cationic) dyes. Basic dyes are water-soluble and produce colored cations in solution. They are mostly amino and substituted amino compounds soluble in acid and made insoluble by the solution being made basic. They become attached to the fibers by formation of salt linkages (ionic bonds) with anionic groups in the fiber. They are used to dye paper, polyacrylonitrile, modified nylons, and modified polyesters. In solvents other than water, they form writing and printing inks. The principal chemical classes are triaryl methane or xanthenes. Basic brown 1 is an example of a cationic dye that is readily protonated under the pH 2 to 5 conditions of dyeing [5]. 

Pigment Blue 24. (Cl 42090). C37H34N209S3Na2. A bright-greenish-blue triaryl-methane pigment. 

The most sensitive spectrophotometric methods for the determination of Re involve the extraction of ion-associates formed by Re04" with basic dyes. From among the triaryl methane dyes, use has been made of Methyl Green (benzene, e = 1.2-10 at 640 nm) [37], fuchsine (formula 27.1) [1] Brilliant Green (benzene, e = 1.010 ) [38], Crystal Violet [39], Victoria Blue 4R (formula 4.28) [40], Rhodamine B [41], Safranine T [42], Nile Blue... 

Shi et al. [161-164] studied a different reaction of an array of triphenylmethane and triarylmethane derivatives such as alkanes, alkenes, alkynes, phosphonates, phosphonic acids and esters, dialkylamines, triaryl acetic acid, triaryl acetonitriles, triaryl acetates, and tetraarylmethanes and published a review of their work [65]. Mainly from product studies they proposed the special case of di-Jt-methane and oxa-di-7u-methane reactions [165], viz. a,a-elimination gives a biaryl and the corresponding carbenes and operates in polar and nonpolar sol-... 

The photochemical reactivity of triaryl systems such as 145 has been studied. The reactions which compounds of this type undergo are of the di-Ti-methane type but involve only phenyl-phenyl interactions. The key reaction is the formation of a carbene by the extrusion of biphenyl following the di-7c-methane process (Scheme The presence... 

Anionic dyes are selected from the group consisting of nitroso compounds, nitro compounds, azo compounds, stilbenes, triaryl-methane compounds, xanthene compounds, quinoline compoimds, thiazole compounds, azine compounds, oxazine compoimds, thi-azine compounds, aminoketone compounds, anthraquinone compounds, indigoid compounds and phthalocyanine compoimds. 

Under similar PTC conditions, Mamoka described the catalytic asymmetric synthesis of triaryl-methanes 107, possessing a chiral aU-carbon quaternary center with excellent ee s (up to 95%), by reaction of trisubstituted enolates derived from 3-aryloxindoles 104 with activated fluorobenzenes 105 in the presence of chiral hifunctional quaternary phosphonium hromide 106 (5% mol) [85]. 

We have used this third strategy to prepare polymeric triaryl-methane dyes chemically bound to condensation polymer backbones. The experimental details and a discussion of some of our results follow. 

The addition of these color-on-demand systems may have an impact on the sensitivity if it interferes the initiation mechanism. Particular reactive initiator radicals (In) can easily abstract a hydrogen from leuco-dyes (XV). This results in the formation of a less reactive triaryl methane radical XVI. Oxidation of this intermediate yields the stable deeply colored cationic structure XVII. Thus, the reactivity/sensitivity of the initiator system reduces requiring to find an agreement between plate sensitivity and color formed. XVI can easily oxidize resulting in formation of the intensively blue-colored triaryl methane cation XVII. 

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