4-phenylenediamine-alcohol complexes

In 1998, Loehlin and co-workers [44] reported the structures of five new crystals of the super-tetrahedral type formed by complementary amines and alcohols. They described the H-bonding networks of three complexes of the diamine type with monoalcohols 4-phenylenediamine (5)-phenol (16) (ratio 1 2, as in 5 16), 4-phenylenediamine (5)-4-phenylphenol (17) (ratio 1 2, as in 5 17), and 4-phenylenediamine (5)-4-chlorophenol (18) (ratio 1 2, as in 5 18) (Scheme 6). Two complexes of 4-phenylenediamine with diols were also reported 4-phenylenediamine (5)-2,6-dihydroxynaphthalene (19) (ratio 1 1, as in 5 19), and 4-phenylenediamine (5)-l,6-hexanediol (20) (ratio 1 1, as in 5 20). The H-bonded networks were... 

Ruthenium complexes catalyze the reaction of primary alcohols with o-phenylenediamine. The catalyst apparently has dual roles in promotion of cyclization and oxidation of the alcohol to aldehyde <91CL1275>. A novel palladium-catalyzed carbonylation of iodobenzene has been linked to base-induced coupling and cyclization with o-phenylenediamine to give 2-arylbenzimidazoles without having to use an arylcarboxylic acid (Scheme 152) <93JOC7016>. 

The Cu(II) complex with polyaniline (emeraldine base) exhibits a higher catalytic efficiency for the dehydrogenative oxidation of cinnamyl alcohol into cin-namaldehyde. Iron(III) chloride is similarly used instead of copper(II) chloride. The catalytic system is applicable to the decarboxylative dehydrogenation of man-delic acid to give benzaldehyde. The cooperative catalysis of polyaniline and cop-per(II) chloride operates to form a reversible redox cycle under oxygen atmosphere as shown in Scheme 3.4. The copper salt contributes to not only oxidation process but also metallic doping. The reduced phenylenediamine anionic species appear to be stabilized by the metallic dopants. 

Integrated systems refer to heterogeneous films on electrodes designed to contain a mixture of constituents with different functions. For instance, electrocatalysis of organics were successfully achieved with the incorporation of catalytic monomers in carbon paste matrix. Examples are oxidations of alcohol by ruthenium 0x0 complex [59] and ascorbic acid by catechol or aminophenol [60], p-phenylenediamine, or tetramethyl-p-phenylenediamine [61], and Prussian blue [62]. A CME prepared... 

Martin-Matute and coworkers described Cp Ir(III) complexes having hydroxyl-, ether-, and alkoxide-functionahzed NHC ligands, and their application in the N-alkylation of amines with primary and secondary alcohob [66]. In particular, the hydroxyl-functionalized complex dbplayed excellent catalytic outcomes, a broad substrate scope, and allowed amines to be alkylated with alcohob at temperatures as low as 50 °C. Indeed, thb hydroxyl-functionalized complex b one of the best catalysts known to date. The authors proposed a metal-ligand bifunctional mechanism for the iV-alkylation of amines with alcohob using this complex, which involves the formation of alcohol/alkoxide intermediates. Complex 38 (Figure 10.10) proved to be excellent for the A/,N -dialkylation of p-, m-, and 0-phenylenediamine with primary alcohob. The authors observed that the dimetal-lic compound 38 performs better than the monoiridium one, suggesting that a cooperative effect between the two metab may be at play [94]. 

Whilst there are no reports in the literature of crystalline products having been obtained from the interactions of adrenochrome with o-phenylenedi-amine. Auterhoff and Hamacher have prepared a phenazine derivative (103) by the interaction of o-phenylenediamine with rubreserine (66) (a compound structurally similar to the aminochromes) [193]. In the same paper, the authors describe the reaction of rubreserine with ammonia in alcohol at reflux temperatures. A complex mixture of products including the phenoxazone derivative, eserine blue was obtained [193]. 

Along with such complexes, their patent included a wide variety of compounds that contain platinum bound through adjoining aromatic amines. Many of these are based on substituted o-phenylenediamine where the substituting group, Ri, can be an acid, alcohol, sulfonic, or other compoimd that can subsequently be connected to a polymer through a condensation or addition reaction of the complex (31). 

Another example was reported in 2012 by the group of Liu. Dinuclear iridium(I) complexes with a bridging saturated dicarbene ligand turned out to be efficient catalysts for the N,N -dialkylation of phenylenediamines with various alcohols (Fig. 24). Interestingly, with simple [Ir(COD)Cl]2 as catalyst, the intermediate imino—amino compound was predominantly formed. The authors claim the much higher selectivity for the diamino product... 

Figure 24 N,N -Dialkylation of phenylenediamines with alcohols catalyzed by a din-udear lr(l) complex.

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