Copper complexes 8-hydroxyquinoline

In acidic solution, the degradation results in the formation of furfural, furfuryl alcohol, 2-furoic acid, 3-hydroxyfurfural, furoin, 2-methyl-3,8-dihydroxychroman, ethylglyoxal, and several condensation products (36). Many metals, especially copper, cataly2e the oxidation of L-ascorbic acid. Oxalic acid and copper form a chelate complex which prevents the ascorbic acid-copper-complex formation and therefore oxalic acid inhibits effectively the oxidation of L-ascorbic acid. L-Ascorbic acid can also be stabilized with metaphosphoric acid, amino acids, 8-hydroxyquinoline, glycols, sugars, and trichloracetic acid (38). Another catalytic reaction which accounts for loss of L-ascorbic acid occurs with enzymes, eg, L-ascorbic acid oxidase, a copper protein-containing enzyme. 

The list ends here other heterocycles have failed to gain significance as coupling components for diazonium salts. The only exception is 2,4-hydroxyquinoline, which is used as a starting material for a copper complex pigment (Sec. 2.10.1.1). 

Terminally metallizable dyes (30) are obtained by the interaction of a diazonium salt and a coupling component containing a chelating system, for example salicylic acid, catechol, salicyl-aldoxime or 8-hydroxyquinoline, and their coordination chemistry is typical of these compounds. Such dyes were rarely used as preformed metal complexes but were usually applied to cotton and then converted to their copper complexes on the fibre to improve their fastness to wet treatments. A typical example is the blue dyestuff (31). 

In the photometric determination of copper, a coupling product formed between the diazonium salt from 2-amino-pyridine and resorcinol, or 4-(2-pyridinylazo)-l,3-benzenediol 21, has been used. Here the formed copper complex under acetate buffer exhibits an absorption peak at 520 nm, which is measured photometrically <2003KPU28>. Similarly for photometric determination of iron(ll), a coupling product formed between the diazonium salt of 2-amino-4,6-dihydroxypyrimidine and 8-hydroxyquinoline, or 6-hydroxy-2-(8-hydroxy-7-quinolinyl)azo-4(l//)-pyrimidinone 22, has been used. This reagent forms a blue complex with iron(n) ions with an absorption maximum at 625 nm that does not interfere with the presence of other metals <2003KD95>. 

N-Arylation of pyridones. The Cu-mediated ChanLam reaction <1999T12757> can be used for N-arylation of pyridones or pyridazinones. Alternative methods use Pb(OAc)4ZnCl2 <2004TL8781> or catalytic amounts of a copper(II) hydroxyquinolinate complex under standard UllmannGoldberg reaction conditions <2006TL149>. 

HYDROXYQUINOLINE COPPER COMPLEX MILMER OXIME COPPER OXINE COPPER OXINE CUIVRE OXYQUINOUNOLEATE de CUA RE (FRENCH) QUINONDO... 

Copper complexes (152) of o-hydroxy-o -(p-aminoethylamino)diarylazo compounds have been prepared ° by the reaction of the corresponding o-chloro-o -hydroxydiarylazo compounds and ethylenediamine in the presence of copper(II) ions (c/. Section 58.2.3. l(iii)(c)). Dyestuffs of this type have been evaluated on nylon but are reported to have very poor fastness properties. Copper complexes such as (153) have been preparedby similar methods. Other, related tetradentate diarylazo compounds, e.g. (154), (155) and (156), are obtained by the reaction of a suitable diazonium salt with the appropriate diarylamine. Chromium(III) and cobalt(III) complexes of dyes of this type, in which the coordination sphere of the metal is completed by a colourless bidentate ligand such as ethylenediamine, salicylic acid or 8-hydroxyquinoline, are reported to have dyeing properties on wool similar to those of the comparably charged 2 1 complexes derived from tri-... 

Incorporation of metal ions into porphyrins is affected by other compounds in solution. Lowe and Phillips (25) found that copper(II) ions were chelated with dimethyl protoporphyrin ester 20,000 times faster in 2.5% sodium dodecylsulfate (SDS) than in 5% cetyl trimethyl ammonium bromide (CATB). The increased activity of SDS treated porphyrin was attributed to electrostatic attraction between anionic micelles formed around the tetrapyrrole nucleus and the metal cation. The authors also reported the influence of certain chelating agents on the rate of copper complex formation. Equimolar concentrations of copper and 8-hydroxyquinoline or sodium diethylthiocarbamate in 2.5% SDS increased the reaction rate 38 and 165 times, respectively, above the control. Secondary chelators may act by removing the hydration sphere on the metal ion increasing its attraction to pyrrole nitrogens (26). 

In 1944, Albert, Gibson and Rubbo [541] found that Cu(II)(8-hydroxy-quinoline)2 was much more effective as a bactericidal and fungicidal agent than 8-hydroxyquinoline (8-HQ). Copper complexes of halo-substituted 8-HQ have been found by Gershon [542] to be even more effective than Cu(II)(8-HQ)2. In addition, both 8-HQ [543] and its copper complex [544] have been found to have antiviral activity. It was suggested that the parent compound inhibited the RNA-dependent DNA polymerase of chick myeloblastosis virus and its copper complex produced the same effect with the RNA-dependent DNA polymerase of the tumourogenic Rous sarcoma virus. 

Lipid-soluble metal complexes such as copper xanthates (from mineral flotation plants), copper 8-hydroxyquinolinate (agricultural fungicide) or alkyl-mercury compounds are particularly toxic forms of heavy metals because they diffuse rapidly through a biomembrane and carry both metal and ligand into the cell. ... 

Synonyms Bis (8-o> quinoline) copper Bis (8-quinolinato) copper Bis (quinolin-8-olato) copper Copper-8 Copper hydroxy quinolate Cop-per-8-hydroxyquinolinate Cop r-8-hydroxyquinoline Cc per oxinate Copper oxyquinolate Copper oxyquinoline Copper quinolate Cop-per-8-quinolate Cupric-8-hydroxyquinolate 8-Hydroxyquinoline copper complex Qxime copper Qxine copper Classification Organic copper compd. 

Hydroxy-2-pyridinethione), sodium salt. See Sodium pyrithione 8-Hydroxyquinoline copper complex. See Copper 8-qulnolinolate Hydroxyquinone. See Hydroquinone 1-Hydroi -s-butylamine. See 2-Aminobutanol... 

Hydroxyquinoline benzoate (salt). See 8-Hydroxyquinoline benzoate 8-Hydroxyquinoline copper complex. See Copper 8-quinolinolate 8-Hydroxyquinoline sulfate CAS 134-31-6 EINECS/ELINCS 205-137-1 Synonyms Bis (8-hydroxyquinolinium) sulfate Chinosol Oxine sulfate Oxyquinoline sulfate (INCI) 8-Quinolinol hydrogen sulfate (2 1) 8-Quinolinol sulfate 8-Quinolinol sulfate (2 1) (salt)... 

The prerequisite for the toxic effect of heavy metals is penetration of the cell wall. For this, certain carriers are needed to transport the heavy metals through lipophilic centres in the cell membrane. Oxines, 2-mercapto-pyridine-N-oxides (III. 11) and dialkyl-dithiocarbamates (III.9) are examples of compounds capable of complexing heavy metal ions such as Cu ions and transporting them into the microbe cell. The carriers named are also toxic, as such, to micro-organisms. But, as a copper carrier, copper-8-hydroxyquinoline is about 100 times more effective than 8-hydroxyquinoline (oxine III. 11.4). Once heavy metal ions have overcome the cell wall with the aid of the carrier molecules, they may compete with magnesium, calcium and potassium ions for receptor sites, inhibit enzymes and cause non-specific precipitation of proteins. 

The antimicrobial activity described here is only valid for 8-hydroxyquinoline and not for the seven other possible hydroxyquinolines which are widely inactive and do not, as does 8-hydroxyquinoline, chelate metal cations, e.g. copper, iron and zinc. Contrary to Oxine the corresponding chelation complexes, e.g. copper 8-hydroxyquinoline (Section 11.5) possess considerable lipid solubility enabling the complex to pass through the cell membrane and then to dissociate into the toxic 8-hydroxyquinoline. However, according to the findings of Block (1983)... 

As is demonstrated in Table 99, Oxine is a broad spectrum microbicide, although it is much more toxic for Gram-positive bacteria than for Gram-negative bacteria. But unfavourable solubility properties and coloration risks have prevented Oxine from becoming an important microbicide for material protection. More popular are the chelate complexes, above all copper 8-hydroxyquinoline (Section 11.5). 

S-hydroxyquinoline, oxine, C9H7ON. Light brown needles, m.p. 15-16 C. Forms insoluble complexes with metals. The solubilities of the derivatives vary with pH, etc. and hence oxine is widely used in analysis. Used for estimating Mg, Al, Zn and many other metals. Many oxinates are extracted and the metal is estimated spectrophotometrically. Derivatives, e.g. 2-meIhyl tend to be specific, for, e.g.. Copper derivatives are used as fungicides. 

Copper quinolinolate (oxine copper) is the chelate of divalent copper and 8-hydroxyquinoline and shares most of its market with copper naphthenate, which is a complex copper salt of mixed naphthenic acids. The principal uses are in wood treatments and some military textiles, where the green color is not objectionable. Copper naphthenate has an odor but is cheaper than oxine. Both copper naphthenate and 2inc naphthenate have performed well in environment tests, with exposure to soil above-ground, as well as concrete (33). 

Hydroxyquinoline (oxine, 8-quinolinol) [148-24-3] M 145.2, m 71-73 , 75-76 , 76 , b 267 pKj 4.91, pK 9.81. Crystd from hot EtOH, acetone, pet ether (b 60-80 ) or water. Crude oxine can be purified by pptn of copper oxinate, followed by liberation of free oxine with H2S or by steam distn after acidification with H2SO4. Stored in the dark. Forms metal complexes. [Manske et al. Can J Research 27F 359 1949 Phillips Chem Rev 56 271 1956.]... 

H. 8-Hydroxyquinaldine (XI). The reactions of 8-hydroxyquinaldine are, in general, similar to 8-hydroxyquinoline described under (C) above, but unlike the latter it does not produce an insoluble complex with aluminium. In acetic acid-acetate solution precipitates are formed with bismuth, cadmium, copper, iron(II) and iron(III), chromium, manganese, nickel, silver, zinc, titanium (Ti02 + ), molybdate, tungstate, and vanadate. The same ions are precipitated in ammoniacal solution with the exception of molybdate, tungstate, and vanadate, but with the addition of lead, calcium, strontium, and magnesium aluminium is not precipitated, but tartrate must be added to prevent the separation of aluminium hydroxide. 

Another terminal bidentate ligand that has been exploited occasionally in bright disazo direct dyes is the sulphated 8-hydroxyquinoline residue (5.15). On aftercoppering, fastness to light and wet tests is enhanced by hydrolysis catalysed by the copper(II) ion and formation of a bidentate 1 2 complex (Scheme 5.3). Apparently, electron withdrawal by sulphur facilitates removal of the sulphite grouping and approach of the copper(II) cation [10]. 

General Order of Rate Constants. The rate constants of electrophilic reactions of aromatic ligands and their metal complexes fall in the order fo, > kML > kffL. The difference between these rate constants becomes greater as the activity of the attacking reagent decreases. When L is a phenolate, HL is the phenol when L is an amine, HL is the corresponding ammonium derivative. The possible synthetic applications of this sequence can be appreciated from the fact that 8-hydroxyquinoline is usually sulfonated with 15 to 30% oleum, while its copper (II) complex can be readily sulfonated in 70% sulfuric add (5). 

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