2,3-Dihydroxynaphthalene complexes, with

Naphthalenediol. 1,5-Dihydroxynaphthalene or Asurol is a colorless material which darkens on exposure to air. It is manufactured by the fusion of disodium 1,5-naphthalenedisulfonate with sodium hydroxide at ca 320°C in high yield. 1,5-Naphthalenediol is an important coupling component, giving ortho-a2o dyes which form complexes with chromium. The metallised dyes produce fast black shades on wool. 1,5-Naphthalenediol can be aminated with ammonia under pressure to 1,5-naphthalenediamine. 

Intorre and Martell (237) have also studied the formation of mixed chelate species in which the zirconium 1 1 complex with the hexa-dentate chelating ligands, ethylenediaminetetraacetic acid, iV-hydroxy-ethylethylenediaminetriacetic acid, and m7 s-cyclohexanediaminetetra-acetic acid, are shown to take up one mole of the bidentate ligands, l,2-dihydroxybenzene-3,5-disulfonate l,8-dihydroxynaphthalene-3,6-disulfonate 8-hydroxyquinoline-5-sulfonate, and acetylacetone (except ZrHEDTA), to form 8-coordinate 1 1 1 species. At least for the zir-conium-EDTA-l,2-dihydroxybenzene-3,5-disulfonate species, there is evidence for dimerization (230). Additionally, the Zr EDTA complex reacts with one mole of the bidentate ligands, 5-sulfosalicyclic acid, alizarin sulfonate, citric acid, and lactic acid to form 1 1 1 complexes tartaric acid and pyrophosphate ions form complexes which could not be identified. The zirconium-nitriloacetic acid complex in the presence of two moles of oxalic acid or l,2-dihydroxybenzene-3,5-sulfonate also forms 1 1 1 complexes in solution. 

Cyclophanes incorporating the diphenylmethane skeleton (4a) with rigid hydrophobic cavities that complex aromatic guests such as durene and 2,7-dihydroxynaphthalene were described by Kenji Koga (Tokyo). By increasing the distance between the (CH2)n spacers from 3.5 to 6.0i, the host (4b) can be rendered suitable for complexation with large aliphatic guests such as deoxycholate. 

Unique methods based on new principles have been developed within the past 10 years. Threonine (27,28,249) is oxidized by lead tetraacetate or periodic acid to acetaldehyde, which is determined by photometric analysis of its p-hydroxydiphenyl complex or iodometric titration of its combined bisulfite. Serine is oxidized similarly to formaldehyde, which is determined gravimetrically (207) as its dimedon (5,5-dimethyldihydro-resorcinol) derivative or photometric analysis (31) of the complex formed with Eegriwe s reagent (l,8-dihydroxynaphthalene-3,5-disulfonic acid). It appears that the data obtained for threonine and serine in various proteins by these oxidation procedures are reasonably accurate. [Block and Bolling (26) have given data on the threonine and serine content of various proteins. ]... 

They next studied the asymmetric oxidative polymerization of achiral 2,3-dihydroxynaphthalene (Scheme 42). The polymerization of this monomer with CuCl2-(-)-sparteine complex resulted in a low yield and gave a low molecular weight oligomer, whereas the polymerization with CuCl-(S)-Phbox quantitatively gave a polymer with Mn of 10 600-15 300. The enantioselectiv-ity attained in this polymerization, however, was estimated to be low, with 43% ee from the model reaction [169]. When vanadyl sulfate (VOSO -Phbox complex was used instead of the copper catalyst system, the enantioselectivity was improved up to 80% ee [170]. Asymmetric cross-coupling polymerization of two kinds of naphthol derivatives was also reported [171,172]. 

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... 

The crystal structures of many o- and p-chlorophenols, but only of a few m-chloro-phenols, are known. Representative examples are l,5-dichloro-2,6-dihydroxynaphthalene (45), a complex between 3,5-dichlorophenol (46) and 2,6-dimethylphenol , and a complex of p-chlorophenol (47) with 1,4-phenylenediamine. The C—OH bond lengths in 45 and 47 are normal (1.364 and 1.361 A, respectively). The same bond in 46 is significantly longer (1.387 A) for unknown reasons. 

Chromotropic acid (l,8-dihydroxynaphthalene-3,6-disulphonic acid, formula 53.1) gives water-soluble, brown-red titanium complexes which differ in composition and colour according to the acidity of the medium [22]. The pH at which the colour is developed is therefore critical. The solutions are usually buffered with formate (pH 3-3.5) or acetate (pH 4-5). 

Mo(0)Cl2(Tp )] reacts with 1,3-, 1,5-, 1,6-, 2,6-, and 2,7-dihydroxynaphthalene, yielding dinuclear complexes [ Mov(0)Cl-(Tp ilb (l -Ci f)H402)] which have been investigated by UV-vis/NIR spectroscopy and variable-temperature magnetic susceptibility studies.73... 

Chromotropic acid (l,8-dihydroxynaphthalene-3,6-disulfonate) reacts with zirconium(IV) to form a 1 1 complex. The apparent equilibrium constant for this system at pH 2.0 and at a metal ion concentration of 5 X 10 M n 0. M KCl, was calculated to be logAzr = 3.63 (466). The initial report (98) of little or no reaction appears to be incorrect. A nitroso derivative of this ligand reacts with zirconium(IV) to give a red-violet precipitate in weak acid solution (535). 

Complexes of tautomeric forms of dihydroxynaphthalenes with AlBtj are discussed in... 

The first clear evidence of inclusion compounds formed by azacyclophanes, both in solution and in the solid state, with aromatic guests was reported in 1980 for the tetrapro-tonated form of 11, existing in aqueous solution below pH 2. Solid 1 1 complexes were obtained between H4ll + and 1,3-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, naphthalene, p-xylene, and durene from acidic aqueous solution or upon extraction into acidic aqueous solution of substrates dissolved in hexane. Complexation in solution, as evidenced by H NMR spectra, revealed an intimate contact between the interacting partners, which was not observed... 

Studies of the redox equilibria between iron(m) and 1,2-dihydroxynaphthalene-4-sulphonate have been reported. At pH < 2, iron(m) spontaneously oxidizes the catechol, but in more basic solution complexes of iron(ui) with one and two equivalents of substrate were detected. The absence of 1 3 species below pH 7 suggests that the complexes might bind molecular oxygen and that the system is well suited to a catalytic role in the aerial oxidation of organic compounds. 

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