Continued investigation of the diazotization and coupling spectrophotometric technique for the determination of aromatic amines with 8-amino-1-hydroxynaphthalene-3,6-disulphonic acid and N-(1-naphthyl)ethylenediamine as coupling agents

Twenty more aromatic amines are determined by the diazotization and coupling spectrophotometric technique, with 8-amino-1-hydroxynaphthalene-3,6-disulphonic acid (H-acid) and N-(1-naphthy)ethylenediamine (N-na) as coupling agents. The following are determined by both methods: 2,4-diaminotoluene, 2-aminobenzotrifluoride, 4-benzoxyaniline, 2,4-dimethyl-6-nitroaniline, 4,5-dimethyl-2-nitroaniline, 2-amino-9-fluorenone, naphthionic acid (sodium salt), 3-aminonaphthalene-2, 7-disulphonic acid (monosodium salt), 2-aminonaphthalene-1-sulphonic acid, 4-aminonaphthalene-1-sulphonic acid and 2,4-dibromoaniline. The following are determined only by the N-na method: 5-aminosalicylic acid, 2-amino-4-nitrophenol, 4-amino-2,6-dichlorophenol hydrochloride, 2,5-dimethoxy-aniline, 4-aminothiophenol, 4,4'-diaminodiphenylmethane, 1-naphthylamine, 4,4'-diaminobiphenyl-2,2'-disulphonic acid and 4,4'-diaminostilbine-2,2'-disulphonic acid. The optimum acidities for the different aromatic amines for the N-na method vary considerably. A number of aromatic amines cannot be determined by either method.     

Features of reactions of polyfluorinated ethyl 4-oxo-2-pnenyl-4H-chromene-3-carboxylates with N-nucleophiles

Ethyl 5,6,7,8-tetrafluoro-4-oxo-2-phenyl-4H-chromene-3-carboxylate in reactions with primary amines is characterized by a chromone-coumarin rearrangement affording 3-[amino(phenyl)methylene]-6,7,8-trifluoro-2H-chromene-2,4(3H)-diones, and ethyl 4-oxo-2-phenyl-5,6,7,8-tetrafluoro-4H-chromene-3-carboxylate characteristically adds the amine at the C² site of the flavone furnishing 3-amino-3-phenyl-2-(2,3,4,5-tetrafluoro-6-hydroxybenzoyl)acrylates which depending on the substituent at the amino group are capable of intramolecular cyclization into 3-[(alkylamino)(phenyl)methylene]-5,6,7,8-tetrafluoro-2H-chromene-2,4(3H)-dione or in the case of benzylamine substituent, into ethyl 1-benzyl-5-hydroxy-4-oxo-2-phenyl-6,7,8-trifluoro-1,4-dihydroquinoline-3-carboxylate. The main process in the reaction of tri- and tetrafluoroflavones with secondary amine (1-methylpiperazine) is the nucleophilic substitution at the C⁷ of flavone. In the reaction with 1,2-phenylenediamine 3-[(2-aminophenyl)amino]-3-phenyl-2-(2,3,4,5-tetrafluoro-6-hydroxybenzoyl)acrylate was obtained from tetrafluoroflavone and 1H-benzimidazol-2-yl(3,4,5-trifluoro-2-hydroxyphenyl)methanone, from trifluoroflavone.     

Polarographic determination of indium(III) after salting-out extraction of the bromide complex into acetonitrile

A simple and sensitive method has been developed for the polarographic determination of indium(III) after solvent extraction into acetonitrile, salted-out from aqueous solution with sodium bromide. The extracted indium(III)-bromide complex gives a well-defined d.c. wave with E(1 2 ) = -0.69 V vs. SCE. The wave-height is directly proportional to the concentration of indium(III) from 1.6 x 10(-6) to 3.0 x 10(-4)M with respect to the original aqueous solution. In the a.c. polarographic method, a linear calibration curve is obtained for indium(III) over the concentration range from 1.6 x 10(-6) to 1.5 x 10(-5)M, and interference from most foreign ions can be eliminated. In particular, 10.0 mg of Fe(III) and 2.5 mg of Tl(III) are tolerated when 1.0 g of ascorbic acid is added. The lower limit of determination is 8 x 10(-8)M indium(III) by the square-wave polarographic method.     

A new sensitive method for the spectrophotometric determination of molybdenum using 3-hydroxy-2-(2'-thienyl)-4H-chromen-4-one

A spectrophotometric method has been developed for the determination of Molybdenum (VI) using 3-hydroxy-2-(2'-thienyl)-4H-chromen-4-one as a complexing agent. The complex formed was dissolved in water in the presence of Triton X-100 and exhibits an absorption maximum at 410 nm. A large number of metal ions like Co(II), Ni(II), Mn(II), Cr(III), Zn(II), Cu(II), Hg(II), Bi(III), Fe(II), Fe(III), Zr(IV), V(V) can be tolerated at an appreciable concentrations. Molar absorptivity and Sandell's sensitivity of the method is 2.80 x 10(5) l mol-1cm-1 and 3.42 x 10(-4) micrograms cm-2, respectively. Beer's law is obeyed in the concentration range of 0.01-0.4 ppm Mo(VI). Aliquots containing 0.2 ppm of Mo(VI) give a mean absorbance of 0.56 with a relative standard deviation of 1.3%.     

Extraction of Mn(II), Co(II), Cr(III) and Fe(III) from succinic acid medium by high molecular weight amines

The extraction behavior of Mn(II), Co(II), Cr(III) and Fe(III) has been studied in high molecular weight amines from succinic acid medium. The effect of different variables, like, type of amine, effect of pretreatment of amine with various acids, type of diluent and concentration of metal, succinate, hydrogen ions and amine, has been investigated. Extraction of Cr(III) and Fe(III) species is proposed and some binary separations achieved.     

Analysis of six aromatic amines stability in workplace measurement

For aromatic amine determination in workplaces, stabilities of six types of carcinogenic aromatic amines (2,4-diaminotoluene, 4,4'-diamino-3,3'-dimethyldiphenylmethane, o-tolidine, 3,3'-dichlorobenzidine, 4,4'-methylenebis(2-chloroaniline), and o-dianisidine) were evaluated with air or argon gas bubbling for 45 min in aqueous solution under light irradiation (desk lamp) and heating conditions. Gas chromatography–mass spectrometry (GC–MS) was used to identify and quantify the aromatic amines. The following conditions were selected: temperature program 70°C (1 min), 7 grad/min up to 120°C (1 min), 10 grad/min up to 300°C (5 min), carrier gas flow rate 1.0 mL/min. 3,3'-Dichlorobenzidine concentration decreased by approximately 10% after irradiation with a desk lamp for 45 min in distilled water, and a monochloro compound was detected by GC–MS. The other aromatic amines were rarely different from the 0-min concentration. The shielding prevented the decomposition of 3,3'-dichlorobenzidine in distilled water.     

Interaction of Fe(III) tetrakis(4-N-methylpyridinium)porphyrin with sodium dodecyl sulfate at submicellar concentrations

Interaction of water soluble Fe(III) tetrakis(4- N-methylpyridinium)porphyrin (Fe(III)TMPyP) with sodium dodecyl sulfate (SDS) in submicellar concentrations has been studied by surface tension, optical absorption, resonance light scattering (RLS), zeta-potential, and energy dispersive X-ray spectroscopy (EDS) measurements. Measurements were conducted for a fixed concentration of Fe(III)TMPyP (6 x 10 (-5) M) and SDS in various concentrations ranging between 6 x 10 (-6) and 6 x 10 (-2) M. Two macroscopic phase transitions, precipitation and redissolution, were observed as function of SDS concentration. The presence of a new surface active porphyrin-surfactant complex was detected. Furthermore, the presence of two oppositely charged Fe(III)TMPyP-SDS bulk moieties has been demonstrated. Possible structures for the different moieties are suggested, and the phase transitions are discussed.     

Quantitative Study of the Interaction between ATP and Aromatic Amines in Aqueous Solution

The interaction between adenosine-5??-triphosphate (ATP) and some aromatic amines (L), namely 1,2-phenylenediamine, 2-(2,4-diaminophenoxy)ethanol, 4-N-(2-hydroxyethyl)2,4-diaminoanisole, 4,5-diamino-1-N-(2-hydroxyethyl)pyrazole and 1,3-bis(2,4-diaminophenoxy) propane, was studied at T=298.15 K and I=0.06 mol?L^?1 in NaCl aqueous solution. For all of the investigated systems, the formation of [(ATP)(L)H _i ]^(i?4) species (i=1 to n+2; n=maximum protonation degree of the amine) with high yields (60?C80?%) were found. The ionic strength and temperature dependences of the complex formation constants were studied using semiempirical equations. The sequestering ability of the aromatic amines toward ATP was defined by calculating the pL₅₀ parameter (the total ligand concentration, as ?log₁₀ C _L, able to bind 50?% of ATP). The dependence of pL₅₀ on pH, ionic strength and temperature is reported. Moreover, it was found that the overall formation constants are reasonably linearly dependent on the number of protons in the complex species. Comparison with the stability of the species of analogous systems, such as ATP?Caliphatic amines and pyrophosphate?Caliphatic amines, is reported. For all these systems a fairly linear dependence was found of the formation constants on the basicity of the amines.     

Synthesis, solution behavior, thermal stability, and biological activity of an Fe(III) complex of an artificial siderophore with intramolecular hydrogen bonding networks

Previously, an artificial siderophore complex, the iron(III) complex with tris[2-[(N-acetyl-N-hydroxy)glycylamino]ethyl]amine (TAGE), was constructed in order to understand the effect of intramolecular hydrogen bonding interaction on the siderophore function, and its structural characterization in the solid state was reported (Inorg. Chem. 2001, 40, 190). In this paper, the solution behavior of the M(III)-TAGE (M = Fe, Ga) system has been investigated using (1)H NMR, UV-vis, and FAB mass spectroscopies in efforts to characterize the biological implication of hydrogen bonding networks between the amide hydrogens and coordinating aminohydroxy oxygens of the complex. The temperature dependence of (1)H NMR spectra for Ga(III) complex of TAGE indicates that hydrogen bonding networks are maintained in polar solvents such as DMSO-d(6) and D(2)O. The UV-vis spectra of the Fe(III)-TAGE system under various pH conditions have shown that TAGE forms a tris(hydroxamato)iron(III) complex in an aqueous solution in the pH range 4-8. By contrast, tris[2-[(N-acetyl-N-hydroxy)propylamido]ethyl]amine (TAPE; TAGE analogue that is difficult to form intramolecular hydrogen bonding networks), which has been synthesized as a comparison of TAGE, forms both of bis- and tris(hydroxamato)iron(III) complexes in the same pH range. Both the stability constants (log beta(FeTAGE) = 28.6; beta(FeTAGE) = [Fe(III)TAGE]/([Fe(3+)][TAGE(3)(-)])) and pM (-log[Fe(3+)]) value for Fe(III)TAGE (pM 25) are comparable to those of a natural siderophore ferrichrome (log beta = 29.1 and pM 25.2). The kinetic study of the TAGE-Fe(III) system has given the following rate constants: the rate of the ligand exchange reaction between Fe(III)TAGE and EDTA is 6.7 x 10(-4) s(-1), and the removal rates of iron from diferric bovine plasma transferrin by TAGE are 2.8 x 10(-2) and 6.0 x 10(-3) min(-1). These values are also comparable to those of a natural siderophore desferrioxamine B under the same conditions. In a biological activity experiment, TAGE has promoted the growth of the siderophore-auxotroph Gram-positive bacterium Microbacterium flavescens, suggesting that TAGE mimics the activity of ferrichrome. These results indicate that the artificial siderophore with intramolecular hydrogen bonding networks, TAGE, is a good structural and functional model for a natural ferrichrome.     

2,4-/2,6-二氨基甲苯在D151树脂上的吸附分离

从10种树脂中筛选出D151树脂对2,4-二氨基甲苯和2,6-二氨基甲苯的吸附分离及其热力学性质进行了研究。 测定了吸附等温线,Freundlich模型对实验的拟合度大于Langmuir模型,其相关系数大于0.99。 热力学研究结果表明,在293～313 K条件下,初始质量浓度为60～80 g/L时,2,4-二氨基甲苯的吸附焓变为-4.3490～-5.7558 kJ/mol,自由能变为-0.2911～-1.0346 kJ/mol,吸附熵变为-12.965～-16.150 J/(mol·K);而2,6-二氨基甲苯的吸附焓变为-2.9645～-3.6054 kJ/mol,自由能变为-0.1610～-0.6384 kJ/mol,吸附熵变为-7.939～-11.005 J/(mol·K)。 进一步研究了D151树脂对二氨基甲苯的动态吸附分离,可以将2,6-二氨基甲苯含量从20%提高至99.93%,将2,4-二氨基甲苯含量从80%提高至99.42%。     

A supramolecular receptor of diatomic molecules (O2, CO, NO) in aqueous solution

A per-O-methylated beta-cyclodextrin dimer, Py2CD, was conveniently prepared via two steps: the Williamson reaction of 3,5-bis(bromomethyl)pyridine and beta-cyclodextrin (beta-CD) yielding 2A,2'A-O-[3,5-pyridinediylbis(methylene)bis-beta-cyclodextrin (bisCD) followed by the O-methylation of all the hydroxy groups of the bisCD. Py2CD formed a very stable 1:1 complex (Fe(III)PCD) with [5,10,15,20-tetrakis(p-sulfonatophenyl)porphinato]iron(III) (Fe(III)TPPS) in aqueous solution. Fe(III)PCD was reduced with Na2S2O4 to afford the Fe (II)TPPS/Py2CD complex (Fe(II)PCD). Dioxygen was bound to Fe(II)PCD, the P(1/2)(O2) values being 42.4 +/- 1.6 and 176 +/- 3 Torr at 3 and 25 degrees C, respectively. The k(on)(O2) and k(off)(O2) values for the dioxygen binding were determined to be 1.3 x 10(7) M(-1) s(-1) and 3.8 x 10(3) s(-1), respectively, at 25 degrees C. Although the dioxygen adduct was not very stable (K(O2) = k(on)(O2)/k(off)(O2) = 3.4 x 10(3) M(-1)), no autoxidation of the dioxygen adduct of Fe(II)PCD to Fe(III)PCD was observed. These results suggest that the encapsulation of Fe (II)TPPS by Py2CD strictly inhibits not only the extrusion of dioxygen from the cyclodextrin cage but also the penetration of a water molecule into the cage. The carbon monoxide affinity of Fe(II)PCD was much higher than the dioxygen affinity; the P(1/2)(CO), k(on)(CO), k(off)(CO), and K(CO) values being (1.6 +/- 0.2) x 10(-2) Torr, 2.4 x 10(6) M(-1) s(-1), 4.8 x 10(-2) s(-1), and 5.0 x 10(7) M(-1), respectively, at 25 degrees C. Fe(II)PCD also bound nitric oxide. The rate of the dissociation of NO from (NO)Fe(II)PCD ((5.58 +/- 0.42) x 10(-5) s(-1)) was in good agreement with the maximum rate ((5.12 +/- 0.18) x 10(-5) s(-1)) of the oxidation of (NO)Fe(II)PCD to Fe(III)PCD and NO3(-), suggesting that the autoxidation of (NO)Fe(II)PCD proceeds through the ligand exchange between NO and O2 followed by the rapid reaction of (O2)Fe(II)PCD with released NO, affording Fe(II)PCD and the NO3(-) anion inside the cyclodextrin cage.     

Novel 2-amino-3-(2,4-dinitrophenylamino) derivatives of 1,4-naphthoquinone

The strong electron withdrawing nature of a 2,4-dinitrophenylamino group when attached to a chloro-naphthoquinone enhances the displacement of the chlorine atom by various aliphatic, cyclic and aromatic amines. A new series of 2-amino-3-(2,4-dinitrophenylamino) derivatives of 1,4-naphthoquinone were prepared. Three absorption maxima in the UV-vis spectra were typical, including one at 430-550 nm assigned to a CT transition.     

An efficient one-pot synthesis of 1,4-disubstituted 3-amino-2-pyridone derivatives via three-component reactions of alkynyl aldehydes and amines with ethyl 2-((diphenylmethylene)amino)acetate

A facile and efficient one-pot synthesis of 1,4-disubstituted 3-amino-2-pyridone derivatives via three-component reactions of readily available alkynyl aldehydes, amines, and ethyl 2-((diphenylmethylene)amino)acetate has been developed. The alkynyl aldehyde substrates and the amine partners can be flexibly varied to achieve a range of 3-amino-2-pyridone derivatives, which could exert interesting chemical and biological properties. The reaction mechanism for the formation of 3-amino-2-pyridone derivatives is briefly explained.     

Synthesis and studies of homopolyamides based on 2,4-bis(6-chlorocarbonyl-2-naphthyloxy)-6-(4-methyl-1-piperazinyl)-s-triazine

Abstract  

Ten homopolyamides have been synthesized by polycondensation of the monomer 2,4-bis(6-chlorocarbonyl-2-naphthyloxy)-6-(4-methyl-1-piperazinyl)-s-triazine and different diamines such as 4,4′-biphenyldiamine, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfonamide, 2,4-diaminotoluene, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, and ethylenediamine. All polyamides were characterized by solubility, density, viscosity measurements, IR, NMR spectroscopy, and thermogravimetric analysis. The products were found to possess high thermal stability.     

Determination of primary aromatic amines in water food simulant using solid-phase analytical derivatization followed by gas chromatography coupled with mass spectrometry

Solid phase analytical derivatization with trifluoroacetic anhydride has been introduced as sample preparation for the determination of primary aromatic amines in water by gas chromatography coupled with mass spectrometry. Water was used as a food simulant for testing migration from laminated flexible food packaging materials. The method was evaluated for 8 primary aromatic amines in 200 ml water samples, which resulted in detection limits in the 0.1-0.4 microg/l range, relative standard deviations in the 4-17% range and acceptable linearity (R2 = 0.997-1.000). Detectable levels of 2,4-diaminotoluene, 2,6-diaminotoluene and 4,4'-methylenedianiline were found in water food simulant from some of the investigated food packaging materials.     

Rapid spectrophotometric determination of ruthenium with diethazine hydrochloride

Diethazine hydrochloride reacts with ruthenium(III) instantaneously at high acidity (sulphuric or hydrochloric acid) to form a red 1:1 complex with absorbance maximum at 515nm. A tenfold molar excess of reagent is necessary for complete complexation. Beer's law is obeyed for 1.0-10.4 ppm of ruthenium(III), with optimum concentration range 2-9 ppm. The molar absorptivity is 5.35 x 10(3) 1.mol(-1) .cm(-1).     

Collection of iron(III) from homogeneous aqueous solutions on membrane filters using Chromazurol B with Triton X-100.

A membrane filtration method was examined concerning the effective collection of iron(III) from a homogeneous aqueous solution with Chromazurol B (CAB), one of the triphenylmethane dyes, as a precipitating reagent in the presence of a non-ionic surfactant, polyethylene glycol mono[4-(1,1,3,3-tetramethylbutyl)phenyl]ether (Triton X-100). A formed blue Fe(III)-CAB complex was collected as a precipitate on a membrane filter by filtration under suction from a homogeneous aqueous solution in the pH range over about 2. The original solution was prepared at a concentration ratio of CAB to Fe(III) of to 10, and that of Triton X-100 to CAB of 10 to 100. It was then adjusted to a pH value of between 1.0 and 6.5. A linear relationship (r = 0.999) was obtained between the initial concentration and the found one of Fe(III) in the range of 2.0 x 10(-5) to 4.0 x 10(-4) mol dm(-3) at a fixed concentration ratio of CAB to Fe(III) of 3 and that of Triton X-100 to CAB of 20. This membrane filtration with CAB and Triton X-100 may be utilized for the separation of Fe(III) as a background species.     

Oxidations of hydrocarbons by manganese(III) tris(hexafluoroacetylacetonate)

Mn(hfacac)(3) is an easily prepared and reactive oxidant (hfacac = hexafluoroacetylacetonate). It forms stable solutions in benzene and methylene chloride but is rapidly reduced in acetonitrile, DMSO, acetone, and ethers. It is reduced by ferrocene to give the Mn(II) complex [Cp(2)Fe][Mn(hfacac)(3)], which has been structurally characterized. Mn(hfacac)(3) also rapidly oxidizes 1-acetylferrocene, 1,1'-diacetylferrocene, and tris(4-bromophenyl)amine. Based on an equilibrium established with tris(2,4-dibromophenyl)amine, a redox potential of 0.9 +/- 0.1 V vs Cp(2)Fe(+/0) is calculated. Mn(hfacac)(3) oxidizes 9,10-dihydroanthracene (DHA) cleanly to anthracene, with a bimolecular rate constant of 6.8 x 10(-4) M(-1) s(-1) at 25 degrees C in benzene solution. In the presence of small amounts of water, the manganese(II) product is isolated as cis-Mn(hfacac)(2)(H(2)O)(2), which has also been structurally characterized. Mn(hfacac)(3) also oxidizes xanthene to 9,9'-bixanthene, 1,4-cyclohexadiene to benzene, and 2,4-di-tert-butylphenol to the phenol dimer. Toluene and substituted toluenes are oxidized to tolylphenylmethanes. Product analyses and relative rates--for instance that p-methoxytoluene reacts much faster than toluene--indicate that the more electron rich substrates react by initial electron transfer to manganese. For the less electron rich substrates, such as 1,4-cyclohexadiene, a mechanism of initial hydrogen atom transfer to Mn(hfacac)(3) is suggested. The ability of Mn(hfacac)(3) to abstract H* is reasonable given its high redox potential and the basicity of [Mn(hfacac)(3)](-). In CH(2)Cl(2) solution, oxidation of DHA is catalyzed by chloride ion.     

Synthesis,structure, properties,and phosphatase-like activity of the first heterodinuclear Fe(III)Mn(II) complex with the unsymmetric ligand H(2)BPBPMP as a model for the PAP in sweet potato

The new heterodinuclear mixed valence complex [Fe(III)Mn(II)(BPBPMP)(OAc)(2)]ClO(4) (1) with the unsymmetrical N(5)O(2) donor ligand 2-bis[((2-pyridylmethyl)-aminomethyl)-6-((2-hydroxybenzyl)(2-pyridylmethyl))-aminomethyl]-4-methylphenol (H(2)BPBPMP) has been synthesized and characterized. Compound 1 crystallizes in the monoclinic system, space group P2(1)/c, and has an Fe(III)Mn(II)(mu-phenoxo)-bis(mu-carboxylato) core. Two quasireversible electron transfers at -870 and +440 mV versus Fc/Fc(+) corresponding to the Fe(II)Mn(II)/Fe(III)Mn(II) and Fe(III)Mn(II)/Fe(III)Mn(III) couples, respectively, appear in the cyclic voltammogram. The dinuclear Fe(III)Mn(II) center has weakly antiferromagnetic coupling with J = -6.8 cm(-1) and g = 1.93. The (57)Fe M?ssbauer spectrum exhibits a single doublet, delta = 0.48 mm s(-1) and DeltaE(Q) = 1.04 mm s(-1) for the high spin Fe(III) ion. Phosphatase-like activity at pH 6.7 with the substrate 2,4-bis(dinitrophenyl)phosphate reveals saturation kinetics with the following Michaelis-Menten constants: K(m) = 2.103 mM, V(max) = 1.803 x 10(-5) mM s(-1), and k(cat) = 4.51 x 10(-4) s(-1).     

Colour reaction of chromium (VI) with N,N-diethyl-1,4-phenylenediame in the presence of ethanol and cyclohexyldiamine tetraacetic acid as well as its application in the species analysis of chromium

A simple, rapid and precise spectrophotometric method for the determination of Chromium (III and IV) has been developed. The reaction of Cr(VI) with N,N-diethyl-1,4-phenylenediamine is almost complete in a twinkling, which yields a red product with a wavelength of maximum absorption at 530 nm. Beer's Law is obeyed in the Cr concentration range of 0-2.0 mug ml(-1). The molar absorptivity is 5.0x10(4) l mol(-1) cm(-1), limit of detection 0.002 mug ml(-1) and relative SD=1.13% for 5.04 mug Cr. The colouring rate and absorbance are not noticeably affected by temperature from 2 to 45 degrees C. The amounts of Cr(VI) and Cr(III) were measured by determining Cr(VI) first under the condition of masking Cr(III) by cyclohexyldiamine tetraacetic acid, and then the total amount by oxidation of Cr(III). The method was applied to the analyses of some industrial waste waters containing Cr with satisfactory results.