Hydroxyquinoline and derivs

When 8-hydroxyquinoline and derivatives of bis(8-hydroxy-quinoline) react with metal ions, coordination complexes and polymers are formed, respectively, which exhibit improved thermal stability. This paper reviews the reaction of first-row transition metal ions with such ligands and their effect on the stabilization of these organic molecules. For the polymers containing divalent Mn, Co, Ni, Cu, or Zn the decomposition temperature is related to the periodic properties of the metal as well as the composition of the ligand to which the metal is coordinated. Trivalent chromium produces a crosslinked polymer when it reacts with bis(8-hydroxy-5-quinolyl)methane, and the thermogram for this polymer is also reported. 

Hydroxyquinoline and derivatives. Trivalent plutonium complexes with 8-hydroxyquino-line (Oxine, Ox) of the formula An(Ox)3 are prepared by precipitation from aqueous solution in the presence of sulyite or dithionite as a reducing agent (to retain An ). Attempts to prepare analogous and Np complexes result in immediate oxidation. 

As chelating agents 8-hydroxyquinoline (and derivatives), dimethylglyo-xime, diphenyldithiocarbazone, sodium diethyldithiocarbamate, sodium N, N phenyl acetyldithiocarbamate, acetylacetone, thenoyltrifluoroacetone, ammonium N-Nitroso-N-phenylthydroxylamine(cupferron), di- n-butyl phos-phoric acid, di(2-ethylhexyl)phosphoric acid, l-nitroso-2-naphthol. 

Little is known quantitatively about substituent effects in the nitration of derivatives of azanaphthalenes. In preparative experiments 4-hydroxy-quinoline, -cinnoline, and -quinazoline give the 6- and 8-nitro compounds, but with nitric acid alone 4-hydroxyquinoline and 2,4-di-hydroxyquinoline react at With nitric acid, 4-hydroxycinnoline... 

Partial rate factors for the nitration of 4-hydroxyquinoline and its derivatives are given in table 10.6. Comparison with the values for quinolinium (table 10.4) show that the introduction of a 4-hydroxy or a 4-methoxy group into the latter activates the 6-position by factors of 3-3 X 10 and 1-6 X 10 , respectively, and the 8-position by factors of 29-5 and 23, respectively. What has been said above makes the significance of partial rate factors which may be calculated for 4-hydroxy-cinnoline uncertain. 

In 1975, Weber and Vogtle showed that open-chained polyethers, 2,6-pyridine-dimethanol, and ortho-xylene derivatives terminated in an 8-quinolinyl group could form stable, 1 1, crystalline complexes with a variety of metal salts. The podands were prepared from 8-hydroxyquinoline and the corresponding dihalides. A typical example is shown in Eq. (7.10). 

There are numerous examples of the conversion of hydroxyquinolines and quinolones into the chloro derivatives using phosphoryl chloride and... 

Pyrimido[l,2-a]quinoline-2-carboxylate (1055, R = Et, R2-R4 = H) was obtained in 50% yield when 2-aminoquinoline was reacted with EMME in boiling Dowtherm A for 20 min (74MIP1). The 6-hydroxy derivative of 1055 (R = Et, R2 = OH, R2 = R4 = H) was prepared in 20% yield when 2-amino-4-hydroxyquinoline and EMME were heated at 170°C for 8 hr (71IJC201). The angular pyrimido[l,2-a]quinoline-2-carboxylate (1055, R = Et, R2-R4 = H) could not be transformed into the linear isomer [77JCS(P1)780],... 

Diazoxine, a red product which accompanies the formation of 8-methoxy-quinoline from 8-hydroxyquinoline and diazomethane, was first encountered by Caronna and Sansone in 1939. Later, it was suggested that the properties of this product were consistent with structure 189 (R = Me, R = R = H). ° Subsequently, this product has been prepared by treatment of the iodide 190 with potassium carbonate, and the betaine structure has been confirmed by spectroscopic and chemical studies. Compound 189 (R = Me, R = R = H) is isolated as hydrated violet-red needles. The UV and visible spectra are strongly dependent on the nature of the solvent the colors of solutions vary from yellow to blue. Bromination gives the 5,7-dibromo derivative (189 R = Me, R = R = Br), which is also obtained from... 

The methyl and benzyl derivatives (289 R = Me, PhCH2 R = H) were described by Claus and Howitz in 1891. Their preparation involves N-alkylation of 6-hydroxyquinoline and base hydrolysis to the quaternary hydroxide which is then desiccated, giving the hygroscopic betaines 289. ° The 2-phenyl derivative (289 R = Me, R = Ph) has been similarly prepared. With methyl iodide, the phenol betaine (289 R = Me, R = H) gives Af-methyl-6-methoxyquinolinium iodide. ... 

Little is known quantitatively about substituent effects in the nitration of derivatives of azanaphthalenes. In preparative experiments 4-hydroxy-quinoline, -cinnoline, and -quinazoline give the 6- and 8-nitro compounds, but with nitric acid alone 4-hydroxyquinoline and 2,4-di-hydroxyquinoline react at C(3).31 With nitric acid, 4-hydroxycinnoline still gives mainly 4-hydroxy-6-nitrocinnoline, but some of the 3-nitro compound can also be isolated.81 51 The change of orientation with reagent could be due to a change to free-base nitration in the more weakly acidic medium, or to the occurrence in nitric acid of nitration via nitrosation.31... 

Azacrown Ethers Functionalized with 8-Hydroxyquinoline and Its Derivatives as Metal-Ion Sensors... 

Extraction techniques that involve a chemical reaction can be classified as nonselective extraction or concentration, when more than one analyte is extracted from the solution by using the organic collectors (e.g., 8-hydroxyquinoline and dithizone derivatives) and selective extraction or separation. The first step in such an extraction technique is the formation of the complex by adding the reagent(s) to the solution of analyte, and after the extraction of the complex in an organic solvent. The problem that can arise in a SIA system with these types of extraction is the precipitate that is formed, and this can contaminate the other sample and also can block the tubing. To avoid these problems, it is necessary either to dilute the sample in such a way that the precipitation equihbria will not be reached and that all the complex will remain dissolved in the solution, or by derivatization of the hgands to... 

It should be noted that some data on complexation of transuranium elements with various N-donor ligands, such as azide ion, isothiocyanate ion, amine-N-polycarboxylic and heterocyclic acids, 8-hydroxyquinoline and its derivatives, were published as early as 1950-1970 [42-77], The quantitative parameters of complexation (number and composition of complexes, stability constants, thermodynamic parameters) were determined using accessible at that time methods (spectrophotometry, potentiometry, ion exchange, solvent extraction). It was shown that transuranium elements in different oxidation states can form complexes with N-donor ligands. However, only presumptive conclusions regarding structure of complexes were drawn at that time,... 

Formation of complexes with ratio M L = 1 3 is observed for the 8-hydroxyquinoline and its derivatives [44]. Americium and plutonium solid compounds were obtained in the form of complexes [Am(Ox)3], [Pu(Ox)3], [Am(DCOx)3], [Am(MCOx)3]. Chelates with halogenated 8-hydroxyquinoline are better extractable from the solution than complexes with 8-hydroxyquinoline. Plutonium (111) easily oxidizes in the presence of 8-... 

Neptunium and plutonium complexes [AnL4] with 8-hydroxyquinoline and its derivatives were obtained in the form of solid compounds (L=Ox, MOx, COx, DCOx) [62], In all cases the coordination number of metal atom is equal to 8, while Th(IV) and U(IV) are known to form complexes H[M(Ox)5] [114], Stability constants were determined by solvent extraction and are equal to logy04=45.28 and logy04=46.O5 for Np complexes with Ox and DCOx, respectively [62],... 

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