effect of some organic compounds in the dissolution of calcium oxalate monohydrate crystals

Calcium oxalate monohydrate [COM] is considered as the main inorganic crystalline compound of human urinary stones. The mechanisms of its formation and dissolution are not well understood. A number of questions about the promoting and inhibiting factors still remain unanswered. Dissolution rates of COM crystals were studied in absence and presence of aniline [A], ethyl-[2-N-arylamino] acetate [AE] and N-phenyl glycinop hydrazide [AH]. The results showed that dissolution of COM crystals measured at 37°C, I= 0.15 mol.dm[-3] and pH = 6.5 was found to follow surface controlled mechanism [n=2]. The effect of aniline A, Ethyl- [2-arylamino] acetate [AE] and Nphenyl glycimoyl hydrazide [AH] on the dissolution rate of COM was found to follow the sequence A>AE>AH. The flexibility and increase of the basisty are, mainly, responsible factors for this order of inhibition

Synthesis, characterization and catalytic activity of copper [II], nickel [II] and cobalt [II] complexes derived from novel hydrazone drivatives of oxamic hydrazide

A series of new coordination complexes of Cu[II], Ni[II] and Co[II] with omaxic hydrazide [L[1]], N,N' - [salicylidene]- oxamic hydrazide [L[2]] and N,N' - bis [naphthalidene] - oxamic hydrazide [L[3]] have been synthesized and characterized by elemental analysis, magnetic moment, IR, UV - Vis spectra nd molar conductance. The thermal behavior of the complexes was investigated by TG A and DTA techniques. The catalytic activity of the complexes to decolorize the Allura-Red [food dye] in presence of H[2]O[2] was studied

Protective role of diethyldithiocarbamate against toxicity of some new antibacterial and antitumor platinum[II] and [IV] organochelates

Aim: Five newly synthesized Schiff base complexes of the platinum [II] and [IV] were screened for their in vitro antibacterial and antitumor activity. Meanwhile, the protective role displayable by diethyldithiocarbamate [DDTC] against the inducible toxicity of two of platinum chelates was investigated as well. Their minimal inhibitory concentrations [MICs] were determined against narrow range of Gram negative and Gram positive bacteria while the antitumor potentials were tested against Ehrlich ascites carcinoma [EAC]. Half LD50 of the two selected antitumor complexes [naphthylaldehyde and diamino hexane [Pt [II] NDAH] and Pt [IV] NEDA] was i.p. injected in male Sprague Dawley rats then their biochemical consequences were investigated. The mode of action studies on intact cells of the most sensitive bacterium [Bacillus subtilis NRRL-B-4378] revealed that Schiff base Pt[IV] chelate derived from naphthylaldehyde and ethylene diamine [Pt [IV] NEDA] had reasonable reducing effects on microbial RNA and protein contents, while DNA was powerfully affected. Regarding their toxicity, Pt[IV] NEDA was found to be less hepato and nephro toxic than Pt[Il] NDAH. The hepatotoxic and nephrotoxic effects of these two platinum complexes seem to be reasonably ameliorated in animals post treated with DDTC as indicated by nearly restoration of normal values of the studied biochemical parameters

Electroreduction of 5-Arylazomethineindazole derivatives in ethanolic buffer solutions at mercury electrodes

Electrochemical behaviour of 5-arylazomethineindazole compounds is studied using DC-polarography, cyclic voltammetry and coulometry. The symmetry coefficient [alpha] and number of electrons [n] consumed in the electrochemical reaction are evaluated, as well as the kinetic parameters [k[s], Delta G] calculated from the cyclic voltammetry data. The medium and substituent effects on the electrode reaction are examined. The mechanism of the electroreduction of the above compounds has been predicted. It involves 4e[-], 5H[+] in acid media, leading to cleavage of the azomethine centre, compared to 2e[-], 2H, in neutral and alkaline media, resulting in the saturation of the [-]C = N- bond

Preparation and spectroscopic characterization of copper [II], Cobalt [II] chelates with multidentate bisazodianils as Ligands

A series of Mn [II] Co [II] and Cu [II] complexes with a number of newly prepared bisazodianil ligands are prepared. The complexes are characterized by elemental and thermal analyses, IR, electronic and ESR-spectra. The composition and geometry of the complexes under study are established

Synthesis, spectral characterization and antimicrobial activity of copper [II] complexes with 2,3-dihydroxyquinoxaline and their adducts with some heterocyclic Nitrogen donors

The reaction of 2,3-dihydroxyquinoxaline, H2dhq with Cu [Ac]2-H2O or CuX2-H2o [X = Cl or Br] gave complexes of stoichiometry [[Hdhq [2]Cu] and [[H2dhq]2CuX2], respectively. Mixed-ligand complexes [[Hdhq[2]CuL[2]] [L = pyridine, 3-picoIine, 4-pincoline, imidazole, 1-methylimidazole or 1,2-dimethylimidazole were also prepared. The complexes were characterized by elemental analyses as well as by infrared, electronic and ESR spectral studies. The IR data showed that H[2]dhq acted as a monobasic or neutral bidentate ligand bonded to copper[II] via enolate and ketoamide-O atoms in [[H[2]dhq[2]Cu] and via ketoamide-O atoms in [[H2dhq]2CuX2]. The electronic spectra indicated that both [[H2dhq]2CuX2] and [[Hdhq]2CuL2] complexes possessed distorted octahedral structures containing CuO[4]X2 and CuO4N2 chromophores, respectively. On the other hand, [[Hdhq[2]Cu] was associated with a square planar structure having a CuO[4] chromophore. ESR studies revealed that metal-ligand covalency increased upon bonding of nitrogen donors to copper [II]. Study of the antimicrobial activity showed that introduction of axial N-donors significantly increased the efficiency of inhibition

Electrochemical studies of 1-ary 1-5- [0-carboxyphenyl] -3-Acetyl formazan and some of its derivatives

The electrochemical behavior of the title compound was studied in the Britton- Robinson buffer series [pH = 2-12] containing 45% [v/v] ethanol. The DC polarograms exhibited a single reduction wave composing 4 electrons corresponding to the saturation reduction of the aliphatic chain in the molecule. The wave height was pH independent, while, the E1/2 was shifted to more negative potential with rise of pH. The CV curves displayed a single irreversible cathodic peak. The effect of substituent on the reduction behavior was discussed and the kinetic parameters of the electrode reaction were evaluated. The various parameters were extracted using the condecon program for convolution, deconvolution and digital simulation studies

Charge transfer complexes of 3-amino-1,2,4-Triazole Schiff Bases with dinitro and trinitro benzenes IR, Hnmr, Uv-vis spectral and conductance studies

Charge transfer complexes of 3-amino-1,2,4-triazole Schiff bases with some dinitro and trinitro compounds were prepared and investigated applying IR, UV vis, 1H-NMR and ESR spectroscopy. The results revealed that complex formation takes place through pi-electron transfer only for the nonacidic or weak acidic acceptors, while with strong acidic acceptors the reaction takes place through both electron and proton transfer. The electrical properties for some CT complexes are investigated in the solid state and correlated with EA and IP. The mechanism of the conduction process in these complexes is also studied

Spectrophotometric method for the determination of copper using nitrose-R-salt as colouring reagent and its application in Serum

A spectrophotometric method for the determination of trace amount of copper in serum is described. It depends upon the formation of golden yellow color on mixing Cu2+ with Nitroso-R-Salt. The different factors affecting the determination of copper were studied. The procedure was applied for the estimation of normal level of copper in serum in relation to certain long acting steroidal contraceptives. The mean recoveries for authentic samples were 95 + 0.107 and 97.01 + 0.084 for serum

Spectrophotometric determination of vanadium [V] with tannie acid and its application to biological fluids

Tannic acid is used in spectrophotometric determination of vanadium [V]. The reagent formed purple-blue color 1:1 complex with vanadium ion in the pH range 5-6, the wave length of maximum absorbence working wavelength, molar absorptivity, 1 mol-1, Sandell's sensitivity [in ug Cm-2] and standard deviation are: 332.2 nm; 8500; 0.028 and 0.52% respectively. The optimum working range is found to be from 0.2 to 10 ppm of vanadium. The stability constant and standard free energy of formation values are reported. The interference of several cations, anions, protein, peptone and some amino acids are investigated. Procedure for the elimination of such interference are suggested. The method has been used successfully for the determination of vanadium in biological fluids

Studies of azo compounds III UV-VIS, IR and 1H-NMR spectroscopic study of monoazodyes based on salicyl-aldehyde

The electronic absorption spectra of some monoazodyes based on salicylaldehyde are studied in organic solvents of different polarities. The spectra are discussed in terms of medium effects and molecular structure. Band assignment is also attempted. The variation of absorbance with pH is utilized for the determination of pKa The important bands in the ir-spectra as well as the main signals of the [1]Hnmr spectra are also discussed in relation to molecular structure

Molar electric conductance of nicotinic and isonicotinic hydrazide metal complexes in correlation with their stoichiometry and substitution

New nicotinic and isonicotinic hydrazides as well as their corresponding metal chelates in the solid state have been prepared and identified. Solution molar electrical conductance was followed as a function of composition, substitution in organic ligands and metal ion variations. Results obtained lead to a better understanding about the mechanism of interaction of the present organic ligand molecules with the different metal ions in which the ligand exhibits the keto form. Based on the metal/ligand ratio, three types of complexes are evaluated. The variation of ligand field strength highly affects the final solution molar electrical conductance. At infinity, the latter has a useful application as a sensitive tool to test for decimal variations in ionic radii of the investigated transition metal ions

formation of binuclear complexes with multidentate ligands II the Co [II], Ni [II] and Cu [II] chelates with o-, m-, and p- [2-OH] naphthalphen

The Co [II], Ni [II] and Cu[II] chelates with o-, m- and p-[2-OH] Naphthalphen are studied spectrophotometrically and conduct metrically in an attempt to throw some light on their stoichiometry and structure. The solid complexes are isolated and studied by infrared, electronic spectra, differential thermal analysis and x-ray powder diffraction

Indirect determination of glucose by atomic absorption spectrophotometry

Although atomic absorption spectrophotometry is commonly used for the direct determination of metals, the method is not suitable for the determination of organic substances. Various methods for the indirect determination of organic compounds are however used frequently 2-Hydroxynaphthoic acid has been determined indirectly through the selective extraction of the Ni [II] 2-Hydroxynaphthoate with nitrobenzene. Phthalic acid is extractable into methyl-isobutyl ketone as the ion pair formed between bis-[neocuproin] Cu [I] and the univalent anion of phthalic acid. A similar method has been employed for the determination of pentachlorophenol. Halonen and Aira were able to determine sugars by their depressive effect on the absorption of calcium. Sugar was also determined by atomic absorption Spectrophotometry after the reduction of CuSO[4] in a carbonate-tartarate solution. Berka et al. studied the oxidation of D-glucose by KMn0[4] in buffered and alkaline media. In the present investigation, and indirect method for the atomic absorption determination of glucose is developed based on the reaction with KMnO[4] under such conditions leading to the quantitative formation of MnO[2]. Both the unreacted KMnO[4] and formed MnO[2] are then determined by atomic absorption Spectrophotometry. Thus, the atomic absorption method for the determination of Mn is indirectly used for the determination of glucose

Ti [IV], Zr [IV] and Th [IV] chelates with some phenylazochromotropic acid dyes

The complexes of Ti [IV], Zr [IV] and Th [IV] with some azo compounds derived from chromptropic acid were studied pot-entiometrically in 0.1 M KNO3 in an attempt to throw some light on their stoichiometry, structure and stability. Formation of 1:1 and 1:2 [Metal: ligand] complexes was established. The solid complexes were isolated and their ir-spectra recorded to ascertain the mode of bonding between the metal ions and ligands

Indirect determination of lactose by atomic absorption spectrophotometry

An indirect atomic absorption method for the determination of lactose is developed. Heptavalent manganese is reduced in weakly acidic solutions by lactose to form insoluble MnO2. The concentration of lactose in the solution is determined from a calibration curve prepared from measurements made on known amounts of lactose. In the meantime the quantity of MnO2 formed is proportional to the concentration of lactose added and the formed Mn[2+] ions are determined by atomic absorption spectrophotometry

formation of binuclear complexes with multidentate ligands 1 the Co [II], Ni [II] and Cu [II] complexes with 2-carboxyphenylazosalicylaldehyde

The formation of complexes of Co [II], Ni [II] and Cu [II] with o-carboxyphenylazosalicylaldehyde are studied by potential-metric and conductometric titrations. The stoichiometry of complexes are also studied by spectrophotometry. The proton-reagent stability constant and conditional formation constant are determined. DTA and ir spectra are also used to study the binuclear complexes formed. The results show that the ligand in the case of the binuclear metal chelates functions as a dibasic tetradentate group

Interference of acids in atomic absorption spectrophotometry of manganese

The effect of mineral and organic acids on atomic absorption determination of manganese is studied. The results show that the atomic absorption of manganese decreased in presence of these acids. The results are discussed in the light of complex formation, density and viscosity of the solution