Triphenylamine, reactions

D) No general reaction can be cited for the preparation of crystalline derivatives of Class (iii). Triphenylamine, when nitrated in acetic acid with fuming nitric acid, gives tri-/>-nitrophenylamine, m.p. 280°. The presence of substituents in the phenyl groups may however complicate or invalidate nitration. 

Reaction of disulfonium dication 34 with electron donor aromatic compounds also affords products of substitution at the sulfonium atom. For example, reaction of dication 34 with aniline, phenol and triphenylamine leads to the corresponding para-substituted sulfonium salts 86 (Scheme 32).97... 

Some apparent anomalies in Table XII are the divergent results of reactions 1 and 4. In reaction 1 the alkyl sodium was generated in situ and the difference in the result may be due to the reaction of something other than the alkyl sodium. The exclusively meta dimetallation reported for reaction 4 is also anomalous since a purely inductive deactivation of the ring should give at least some of the para isomer. Another anomaly is the meta orientation in reaction 8. The nitrogen of triphenylamine is not very basic, however, and might not participate in the special mechanism proposed for reaction at the ortho position. 

Triphenylamine (TPA), AWW W -tetramethyl-p-phenylenediamine (TMPD) and dimethylaniline (DMA) have been popular substrates for reaction under pulse radiolysis conditions. One of the earlier reports dealt with the formation of the radical cation of TMPD by reaction (k = 3 x 108 M 1 s 1) with the peroxy radical derived from oxidation of methylene chloride (CHCI2O2) by pulse radiolysis26. DMA is also oxidized to its radical cation by the same reagent (k = 2.5 x 107 M 1s 1). Since then it has been... 

However, the cell in Fig. 9.2(b) has a disadvantage in that the concentration of the electrogenerated substance decreases with increasing distance from the OTE surface. Because of this, simulation of the reaction is very difficult, except for the first order (or pseudo-first-order) reactions. For more complicated reactions, it is desirable that the concentration of the electrogenerated species is kept uniform in the solution. With a thin-layer cell, a solution of uniform concentration can be obtained by complete electrolysis, but it takes 30 s. Thus, the thin-layer cell is applicable only for slow reactions. For faster reactions, a column-type cell for rapid electrolysis is convenient. Okazaki et al. [7] constructed a stopped-flow optical absorption cell using one or two column-type cells (Fig. 9.4) and used it to study the dimerization of the radical cations (TPA +) of triphenylamine and the reactions of the radical cation (DPA +) of 9,10-diphenylanthracene with water and alcohols. Using the stopped-flow cell, reactions of substances with a half-life of 1 s can be studied in solutions of uniform concentrations. 

Oxidative cleavage by means of electrochemically generated cation-radicals is also possible thus benzyl ethers may be cleaved and carboxylates decarboxylated using cation-radicals of brominated triphenylamines in acetonitrile containing a weak base.34 35 Such as indirect reaction makes it... 

The stability of the semireduced Eosin radical produced by reduction with triethanolamine is similar to that reported for the radical in aqueous solution [209], Our results indicate that the lifetime is substantially shorter when it is generated by reduction with triphenylamine. We attribute this difference to the ability of the triethanolamine radical cation to form the a-amino radical by loss of a proton, as shown below, thus preventing the reaction of the radical by reverse electron transfer (Eq. 18). 

The nitration of triphenylamine derivatives by Cu(N03)2 in acetic anhydride at room temperature proceeds readily, introducing up to three nitro groups.22 Reaction... 

Triphenylamine derivatives are known to be efficient hole transport materials and are widely used in organic light-emitting devices. Thelakkat et al. reported the synthesis of a 2,2-bipyridine ligand capped with polyfvinyl-triphenylamine) at both ends.97 The polymer chain was synthesized by the atom transfer radical polymerization of 4-bromostyrene using 4,4-bis (chloromethyl)bipyridine as the initiator (Scheme 18). The bromide groups were then replaced by diphenylamine in the presence of palladium catalyst. Polymer 33 was then obtained by the metalation reaction. 

Molecular Recognition and Chemistry in Restricted Reaction Spaces. Photophysics and Photoinduced Electron Transfer on the Surfaces of Micelles, Dendrimers and DNA [N. J. Turro, J. K. Barton, D. A. Tomalia, Acc. Chem. Res. 1991, 24, 332], Self-Assembly in Synthetic Routes to Molecular Devices. Biological Principles and Chemical Perspectives A Review [J. S. Lindsey, New J. Chem. 1991,15, 153], Amorphous molecular materials synthesis and properties of a novel starburst molecule, 4,4, 4 -tri(N-phenothiazinyl)triphenylamine [A. Higuchi, H. Inada, T. Kobata, Y. Shirota, Adv. Mat. (Weinheim, Ger.) 1991, 3(11), 549-550],... 

The ability of trichlorogermane as an acid to form stable organic salts having the GeCl3 anion was first observed in the study of the reaction of HGeCl3 with triphenylamine. It was found that at room temperature their interaction lead to the formation of an unusual iminium salt, i.e. trichlorogermanate 3,5-fe(trichlorogermyl)cyclohexylidenediphenyliminium 1 in 92% yield (equation 2)35,36. 

A change in the conditions under which the reaction between triphenylamine and HGeCl3 is carried out leads to the formation of other products. For instance, when the temperature of the reaction is increased from 20 to 80 °C and there is a 4 to 5-fold molar excess of HGeCl3, the cis-1, which is initially formed, is converted into the formal hydrogenation product l-diphenylamino-3,5-bis(trichlorogermyl)cyclohexane 60, which is isolated with a yield of 53% in the form of the methylated derivative 61 (equation 49). 

Triphenylamine (125 g) was dissolved in 5 L ethyl alcohol, HgO (150g) added at 60°C, followed by (100 g), and the reaction refluxed 2 hours. Thereafter, the mixture was hot filtered, the residue washed with acetone, and upon cooling, crystals deposited. The crystals were purified by chromatography using silica gel with toluene and 52 g product isolated. 

A number of organic solutes undergo reaction with AICI3. For example, aromatic amines dissolve in the room-temperature molten electrolyte butylpyridinium chloride. Triphenylamine (TPA) shows two stages of oxidation upon polarographic examina-... 

A fundamental route for the preparation of simple tetraalkylphosphonium salts is the reaction of a tertiary phosphine with a haloalkane or other substrate upon which a simple nucleophilic substitution reaction can occur. (In comparing phosphorus nucleophiles with the corresponding nitrogen-centered nucleophiles, it must be remembered that the phosphorus is significantly more nucleophilic than is the nitrogen. For example, while triphenylamine is devoid of nucleophilic character in reaction with ordinary haloalkanes, triphenylphosphine exhibits high reactivity.) Reactivity of the phosphorus in such nucleophilic substitution reactions, as with other types of nucleophiles, decreases with increasing substitution about the electrophilic site of the substrate. 

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