Microdistributions of Electrolytic Alloys and Their Components

Microdistributions of Cu–Ni and Cu–Co alloys electrodeposited from pyrophosphate; Ni–Cu, from sulfate–chloride and pyrophosphate–ammonium; Cu–Zn, from pyrophosphate and cyanide; Cu–Cd, from sulfate and pyrophosphate; and Ni–Cd, Ni–Co–Cd, and Zn–Cd, from sulfate, sulfate–chloride, pyrophosphate, chloride–ammonium, and acetate electrolytes are studied. The coatings' microprofile depends on the kinetics of reduction of each component and mutual influence of electrochemical processes at the cathode. Copper accelerates and cadmium inhibits the reduction of the second component of alloys, no matter the electrolyte type, reduction kinetics, and metal nature. In antileveling conditions, the diffusion-controlled Cu reduction accelerates the reduction of the second component of alloys and ensures deposition of coatings whose microprofiles are more uniform than expected from diffusion limitations only. Depolarizing action of Cu during the Cu–Zn deposition from a cyanide electrolyte can completely neutralize differences in the rates of supply of reduced metal ions; hence a constant chemical composition of the coating over its microprofile. Inhibiting action of the diffusion-controlled Cd deposition provides for leveling properties of electrolytes from which Ni–Cd, Ni–Co–Cd, and Zn–Cd alloys are deposited; the chemical composition of these deposits is nonuniform over their microprofiles.     

Importance of bulk properties in the structure and evolution of cleavage surfaces of quasicrystals

The present work reviews the recent achievements in probing bulk properties of quasicrystals by using cleavage surfaces and surface sensitive techniques. In particular, it is shown that the cluster–subcluster-based structure of the cleavage surface of icosahedral Al–Pd–Mn quasicrystals can be related to the presence of stable atom clusters in the bulk, which force the crack front to circumvent them. Furthermore, by subjecting cleavage surfaces of differently pre-annealed Al–Pd–Mn quasicrystals to a post-cleavage heat treatment, we demonstrate that bulk vacancies migrate toward the surface, where they initiate structure and composition changes. These studies allow us to characterize Al–Pd–Mn quasicrystals with respect to their bulk vacancy concentration. As-grown Al–Pd–Mn quasicrystals are found to contain a supersaturation of all chemical species of vacancies in near stoichiometric composition, whereas long term pre-annealed material has a much lower, and predominantly Al, vacancy concentration. Analogous experiments for decagonal Al–Ni–Co quasicrystals show that as-grown Al–Ni–Co has a lower vacancy concentration than as-grown Al–Pd–Mn.     

Solvent extraction and separation of some lanthanides and americium by extraction chromatography in the system Aliquat-336 — LiNO3 and HNO3

Summary The liquid-liquid extraction of Nd, Eu, Ho, and Am nitrates by means of the radiotracer method in the system tri-caprylmonomethyl ammonium nitrate /Aliquat-336/ — lithium nitrate and nitric acid was investigated.The mixture of tracer quantities of Eu–Am, Nd–Pr, Sm–Pm, Gd–Eu, Er–Ho, Tm–Er, Yb–Tm, and Lu–Tm were separated by column partition chromatography.

---

Lösungsmittelextraktion und Trennung einiger Lanthanide und Americium durch Extraktions-chromatographie im System Aliquat-336 — LiNO₃ und HNO₃

Zusammenfassung Es wurde die Flüssig-Flüssig-Extraktion von Nd-, Eu-, Ho- und Am-Nitraten mit Hilfe radioaktiver Markierung im System Tri-caprylmonomethyl-ammoniumnitrat-/Aliquat-336/-Lithiumnitrat und Salpetersäure untersucht.Die Markierungsgemische von Eu–Am, Nd–Pr, Sm–Pm, Gd–Eu, Er–Ho, Tm–Er, Yb–Tm und Lu–Tm wurden durch Säulen-Verteilungs-Chromatographie getrennt.

---

Extraction par solvant et separation de quelques lanthanides et d'americium par chromatographie d'éxtraction dans le système «Aliquat-336, LiNO₃, HNO₃»

Sommaire On a étudié, au moyen de la méthode des radiotraceurs, l'éxtraction liquide-liquide de nitrates de Nd, Eu, Ho et Am dans le système «nitrate de tri-caprylmonométhyl ammonium [Aliquat-336], nitrate de lithium, acide nitrique».Les mélanges de Eu–Am, Nd–Pr, Sm–Pm, Gd–Eu, Er–Ho, Tm–Er, Yb–Tm et Lu–Tm à la dose des traceurs radioactifs, ont été résolus en leurs composants chromatographie de partage sur colonne.

     

Polarographic and voltammetric determination of trace amounts of 2-nitronaphthalene

The polarographic behaviour of 2-nitronaphthalene was investigated by DC tast polarography (DCTP) and differential pulse polarography (DPP), both at a dropping mercury electrode, and differential pulse voltammetry and adsorptive stripping voltammetry, both at a hanging mercury drop electrode. Optimum conditions have been found for the determination of 2-nitronaphthalene by the given methods in the concentration ranges of 2×10^–6–1×10^–4, 2×10^–7–1×10^–4, 1×10^–8–1×10^–4 and 2×10^–9–1×10^–8 M, respectively. Practical applicability of these techniques was demonstrated by the determination of 2-nitronaphthalene in drinking and river water after its preliminary separation and preconcentration using liquid–liquid and solid-phase extraction with limits of determination of 3×10^–10 M (drinking water) and 3×10^–9 M (river water).     

Vibrational frequencies and structural determinations of tetraisocyanatogermane

The normal mode frequencies and corresponding vibrational assignments of Ge(NCO)₄ are examined theoretically using the 98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of six types of motion predicted by a group theoretical analysis (Ge–N stretch, N–C–O symmetric stretch, N–C–O asymmetric stretch, N–C–O bend, Ge–N–C bend, and N–Ge–N bend) utilizing the T_d symmetry of the molecule. Uniform scaling factors were derived for each type of motion. Predicted infrared and Raman intensities are reported.     

Synthesis and Structure of Organoantimony Peroxides

Organoantimony peroxides (Ar₂SbO)₄(O₂)₂ (Ar = Ph, p-Tol) were synthesized by oxidation of triarylantimony with hydrogen peroxide in the presence of nitrosophenol or 4-chlorophenol in an ether solution. X-ray diffraction analysis of peroxides obtained revealed that four antimony atoms have octahedral coordination and are connected via bridging oxygen atoms and two peroxide groups. The C–Sb, Sb–O_br, Sb–OO, and O–O distances are equal to 2.106–2.127, 1.958–1.974, 2.202–2.246, 1.471, 1.470 Å (Ar = Ph) and 2.086–2.139, 1.932–1.983, 2.215–2.289, 1.445–1.466 Å (Ar = p-Tol).     

Synthesis and Structures of Tetra- and Triarylantimony Oximates

Tetraphenylantimony acetophenoneoximate (I) and tetra-n-tolylantimony 3-nitrobenzaloximate (II) were synthesized by reacting pentaarylantimony with oxime or triarylantimony dioximate in toluene. Tri-n-tolylantimony bis(acetophenoneoximate) (III) and triphenylantimony bis(cyclohexanoneoximate) (IV) were synthesized by reacting triarylantimony with oxime and hydrogen peroxide. The structures of compounds I–IV were determined using X-ray diffraction analysis. The antimony atoms in I–IV are coordinated to the axial oxime groups to form a distorted trigonal bipyramid. The Sb–C(Ph) and Sb–O bond lengths and Sb...N intramolecular contacts in structures I and II lie within 2.114–2.135, 2.137–2.154, and 2.857–2.871 Å, respectively; the respective values in structures III and IV are 2.097–2.112, 2.058–2.080, and 2.779–2.874 Å.     

Diffusion coefficients of 2-fluoroanisole, 2-bromoanisole, allylbenzene and 1,3-divinylbenzene at infinite dilution in supercritical carbon dioxide

The Taylor–Aris chromatographic technique was employed for the determination of diffusion coefficients of 2-fluoroanisole, 2-bromoanisole, allylbenzene and 1,3-divinylbenzene at infinite dilution in supercritical carbon dioxide from 313.16 to 333.16 K and pressures between 15 and 35 MPa. As expected, the diffusivities rise when temperature increases and pressure decreases. Numerous predictive equations are compared with experimental data: Lai–Tan, Liu–Ruckenstein cluster formula, Woerlee, Hippler–Schubert–Troe, Catchpole–King, Eaton–Akgerman, He, He–Yu, Liu–Silva–Macedo, Funazukuri and coworkers, Dariva–Coelho–Oliveira, Zhu–Lu–Zhou–Wang–Shi and the Liu–Ruckenstein RHS formula. The equations of He, He–Yu and Catchpole–King are the best of all, but cannot be used in the whole range of temperatures and solvent densities.     

Indirect atomic absorption and atomic emission spectrometric determination of antazoline,hydralazine and amiloride hydrochlorides and quinine sulphate

Ion-association complexes of antazoline HCl [I], hydralazine HCl [II], amiloride HCl [III] and quinine sulphate [IV] with [Co(SCN)₄]^2– and [Co(NO₂)₆]^3– were precipitated and the excess unreacted cobalt complex was determined. A new method using atomic emission and atomic absorption spectrometry for the determination of the above drugs in pure solutions and pharmaceutical preparations is given. The drugs can be determined in the ranges 0.3–3.0, 0.19–1.96, 0.3–3.0, and 0.78–7.82 mg/25 ml solutions of I, II, III, and IV, respectively, with mean relative standard deviations of 0.65–2.03 % and recovery values of 95.76–101.2% indicating high precision and accuracy.     

Activation Parameters for the Formation and Decay of Partial-Charge-Transfer Exciplexes of 9-Cyanoanthracene, 1,12-Benzperylene, and Pyrene

The factors affecting the rate of formation and decay of exciplexes with partial charge transfer, which form in the kinetic region of photoinduced electron transfer (G ^* _et > –0.2 eV), were studied. The rate of formation of exciplexes is controlled mainly by the diffusion of reactants and the low steric factor (0.15–1.0). The activation enthalpy and entropy for the exciplex formation (9–13 kJ mol^–1 and –(12–28) J mol^–1 K^–1) are close to the activation enthalpy and entropy of diffusion, respectively. Charge transfer in an exciplex and polarization of the medium generally occur after passing the transition state. In contrast, the activation enthalpy of exciplex decay (its conversion into the reaction products) is close to zero (±6 kJ mol^–1) and the activation entropy is strongly negative –(80–130) J mol^–1 K^–1.     

Geochemical and gamma spectrometric analysis of ores and hostrocks of the Kanawa uranium occurrence in NE Nigeria

The Kanawa mineralization is one of the numerous low grade U-occurrences in the Gubrunde horst, NE Nigeria. Eighty nine samples consisting of ore and host rocks have been analyzed for 12 elements and 3 isotopes by atomic absorption spectrometry, colorimetry and direct -spectrometric methods and the data described using multivariate statistical techniques. The results show an enhancement of U, Mn, P₂O₅, Fe₂O₃, CaO,²¹⁰Pb,²²⁶Ra and²³⁴Th in the ore zones. The element/isotopic associations (U–P₂O₅–²¹⁰Pb–²²⁶Ra–²³⁴Th), (Na₂O–K₂O–MgO), (Fe₂O₃–MnO–CaO–Cu) were established in the mineralized rhyolites, while (P₂O₅–²¹⁰Pb–²²⁶Ra–²³⁴Th), (Na₂O–K₂O–MgO–Zn) and Fe₂O₃–Mn–U) occur in the altered/unmineralized rocks. The variation in the pattern of association of Cu, U, Zn and CaO could be ascribed to their remobilization, depletion, enrichment or introduction in the ore zone by hydrothermal solutions. The elements/isotopes U, Zn, Cu, P₂O₅,²²⁶Ra,²¹⁰Pb,²³⁴Th or their ratios could in addition to Pb, Ba, Ce, Sm be used as pathfinder elements in prospecting concealed ores in NE Nigeria.     

A study of the chemiluminescence behavior of myoglobin with luminol and its analytical applications

A chemiluminescence signal at 425 nm was observed when ferric state myoglobin was mixed with luminol in alkaline medium. Because the signal was remarkably enhanced in the presence of Fe(CN)₆ ^4–, analytical applications were investigated in a flow-injection system. The increase in chemiluminescence was linearly dependent on myoglobin concentration in the range 0.1 to 100 nmol L^–1, and the limit of detection was 0.04 nmol L^–1 with relative standard deviation 3.2% (3). It was also found that binding of Mb with the ligands CN^–, SCN^–, and F^– significantly inhibited the chemiluminescence reaction. The linear dynamic ranges for the ligands were 1.0–300.0, 0.1–3.0, and 0.5–100.0 nmol L^–1, and the limits of detection (S/N=3) 0.4, 0.04, and 0.2 nmol L^–1, for F^–, CN^–, and SCN^–, respectively. The relative standard deviations were 5.32%, 6.13%, and 3.38% for 0.1 nmol L^–1 CN^–, 0.5 nmol L^–1 SCN^–, and 1.0 nmol L^–1 F^–, respectively. At a flow rate of 2.0 mL min^–1 the assay could be accomplished in 1 min, including sampling and washing. The method has been successfully applied to the determination of myoglobin in human urine and F^– in water samples. A possible mechanism of chemiluminescence production by myoglobin and luminol is presented.     

Effect of Cathode Potential on Electrosynthesis and Physicochemical Properties of Styrene and Methyl Methacrylate Copolymers

The voltammetry, ESR and UV spectroscopy methods and quantum chemical calculations (PPDP/2) are used to determine the nature of active centers, the anionic mechanism of electrochemical copolymerization (ECP) of styrene (St) and methyl methacrylate (M) at the cathode surface, and the radical-anion mechanism in aprotic solvents. The composition, microstructure, and dielectric properties of copolymers are determined by the cathode potential, which is due to a change in the nature of inducing species (M°^–, °M–M^–, ^–M–M^–, St^2–) and in the ratio of their concentrations during ECP.     

Experimental X-ray absorption edge structures of aluminium and carbon, nitrogen and oxygen in polyimide

Experimental X-ray absorption cross sections were abstracted from synchrotron radiation transmission measurements of aluminium coated polyimide membranes. Edge structure data are presented in tables for carbon in the range 283.4–400 eV, for nitrogen in 402–529 eV, for oxygen in 529.5–750 eV and for aluminium in 60–283.2 eV and 1554–1800 eV.     

Densities and Excess Molar Volumes of Binary and Ternary Mixtures of Aqueous Solutions of 2,2,2-Trifluoroethanol with Acetone and Alcohols at the Temperature of 298.15 K and Pressure of 101 kPa

Excess molar volumes V_m^E of the binary mixtures of (trifluoroethanol + 1-propanol), (trifluoroethanol + 2-propanol), (acetone + water), (methanol + water), (ethanol + water), (1-propanol + water), (2-propanol + water), and the ternary mixtures of (trifluoroethanol + methanol + water), (trifluoroethanol + ethanol + water), (trifluoroethanol~+ 1-propanol + water), (trifluoroethanol + 2-propanol + water) and (trifluoroethanol + acetone + water) were measured with a vibrating tube densimeter at the temperature of 298.15 K and the pressure 101 kPa. The extrema in V_m^E of trifluoroethanol mixtures occur at –0.690 cm³-mol^–1 for (trifluoroethanol + 1-propanol), at –0.990~cm³-mol^–1 for (trifluoroethanol + 2-propanol); at 0.562 and –0.973 cm³-mol^–1 for (trifluoroethanol + methanol + water), at 0.629 and –0.973 cm³-mol^–1 for (trifluoroethanol + ethanol + water), at 1.082 and –0.659 cm³-mol^–1 for (trifluoroethanol~+ 1-propanol + water), at 0.998 and –0.991 cm³-mol^–1 for (trifluoroethanol~+ 2-propanol + water), and at 0.515 and –1.472 cm³-mol^–1 for (trifluoroethanol + acetone + water). The experimental ternary V_m^E values were predicted by empirical expressions using binary solution data.     

Homo and heteronuclear complexes of dioxime ligands

The mononuclear fragments [Cu(HDopn)(OH)2]+ and [Cu(HPopn)(OH)2]+, [H2Dopn=3,3-(trimethylene- dinitrilo)-dibutan-2–one dioximate and H2Popn, = 3, 3-(phenylenedinitrilo)-dibutan-2–one dioximate] were used to prepare four binuclear complexes [(OH2)Cu (Dopn)Cu(ditn)]2+, [(OH2)Cu(Dopn)Ni(ditn)(H2O)]2+ (ditn=diethylenetriamine) and [(OH2)Cu(Popn)Cu(L) (H2O)]2+ (L=2,2-bipyridine or 1,10–phenanthroline). Two trinuclear complexes, [{Cu(Popn)(OH2)}2M (H2O)n]2+ (when M=CuII, n=1; M=ZnII, n= 2), have been synthesised and characterised by elemental analyses, f.a.b. mass, i.r., electronic, e.s.r. spectroscopy and variable temperature (5–300K) magnetic susceptibility measurements. A strong antiferromagnetic interaction (J=–545cm–1 to –700cm–1) has been found for the binuclear copper(II) complexes. The X-band e.s.r. spectra of these complexes at 300K and for trinuclear complexes at 120K indicate square-pyramidal geometry for the copper centres with a (dx2–y2)1 ground state. The binuclear complex of copper(II)–nickel(II) centres with antiferromagnetic interaction (J=–107 cm–1) is described, and moderately strong zero-field splitting within the quartet state leads to Kramers doublet, as indicated by X-band e.s.r. spectra of this complex. The trinuclear copper(II) complex with an antiferromagnetic interaction (J= –350cm–1) is also described. The heterometallic trinuclear copper(II)–zinc(II)–copper(II) system shows a very weak interaction (J–1cm–1).     

Syntheses and Characterization of Polymetallosiloxanes from Silicic Acid and Metal Chlorides

Syntheses and characterization of polymetallosiloxanes by the non-hydrolysis sol-gel process using no metal alkoxides were investigated. The reaction of silicic acid (SA) with MCl₄ (M = Ti, Zr) in the molar ratios SA/MCl₄ = 0.5–3.0 using a tetrahydrofuran-methanol solvent formed polymetallosiloxane (PMS), which was insoluble in organic solvents regardless of the molar ratio. The PMS was isolated as esterified polymetallosiloxane by esterification with isopropyl alcohol for various periods, which were soluble in methanol, acetone, and tetrahydrofuran. The number average molecular weight was 1000–3200 for esterified polytitanosiloxane and 3400–11000 for esterified polyzirconosiloxane. Esterified polymetallosiloxanes had no melting point but decomposition point. The results of analytical data indicated that esterified polymetallosiloxane and/or polymetallosiloxane consisted of the main chain of Si–O–Si and Si–O–M linkage with the pendants of alkoxy, silanol, and chloro group.     

Neutron Activation Analysis of Bottom and Fly Oil Ash Leachates

Seven samples of oil fly and bottom ashes were leached with water using a Canadian standard test method for shake extraction of solid waste. The concentrations of 20 elements in the leachates were determined by the computerized systematic instrumental absolute neutron activation analysis. The ranges of concentrations (in ppm) found for the elements in the leachates were: Al (3–526), Ba (0.5–6), Ca (100–695), Cl (13–59), Co (1–6.3), Cr (0.2–6.6), Cs (0.03–0.4), Eu (0.003–0.01), Fe (28–690), K (42–464), La (0.3–49), Mg (214–3150), Mn (1.2–20), Na (88–4050), Sb (0.04–0.4), Sc (0.003–0.07), Sr (1.2–23), U (0.07–1), V (1.2–4540) and Zn (2.3–200). These findings were compared with the maximum concentrations allowed for these elements by Canadian regulations. The concentrations of Cr and U were found to be higher than their permissible limits on 7 occasions. The purpose of this study was to determine the background levels of different elements in oil ash leachates, in order to evaluate their potential impact on underground water.     

Vibrational frequencies and structural determination of 1,3-difluoro-1,2-propadiene

The normal mode frequencies and corresponding vibrational assignments of 1,3-difluoro-1,2-propadiene in are examined theoretically using the GAUSSIAN 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of eight types of motion (CC stretch, C–H stretch, C–F stretch, H–C–F scissors, H–C–F wag, H–C–F rock, H–C–F twist, and CCC bend) predicted by a group theoretical analysis. Comparing the vibrational frequencies with IR and Raman spectra available in the literature, a set of scaling factors are derived. Predicted infrared and Raman intensities are reported.     

Structure and torsional flexibility of the linkage between guanine and fluorene residues in the deoxyguanosine–aminofluorene and deoxyguanosine–acetylaminofluorene carcinogenic adducts

Potential energy surfaces for rotations around two central CN bonds in N-(deoxyguanosin-8-yl)-2-acetylaminofluorene (AAF–dG) and its deacetylated derivative (AF–dG) were studied using Amber 95 molecular mechanics. Both of these adducts are known to be strong mutagens and carcinogens. New Amber 95 force field parameters were derived for the linkage connecting guanine and fluorene moieties in AAF–dG and AF–dG. For this purpose, we determined ab initio MP2/cc-pVDZ//B3-LYP/6-31G* and polarized continuum model Hartree–Fock/6-31G* potential energy surfaces of smaller model systems that included the N-methylimidazole–acetylaniline and N-methylimidazole–aniline adducts. The molecular mechanics parameters were adjusted to minimize differences between the gas-phase ab initio and molecular mechanics surfaces of these model systems. The resulting parameters were transferred to AF–dG and AAF–dG. The barrier for the rotation of the fluorene residue in AF–dG was found to be less than 2 kcal/mol. Such a small barrier renders the fluorene moiety freely rotatable at room temperature. In contrast, the fluorene rotation in AAF–dG is hindered by a significantly larger barrier of 10 kcal/mol. This barrier corresponds to conformations in which the fluorene and acetyl groups lie in the same plane, and is largely due to steric repulsion. Similarly, the coplanar arrangement of guanine and the bridging amino or acetyl groups is disfavored by 5–10 kcal/mol, with AAF–dG again being the more rigid of the two molecules. Energy minima for a rotation around a bond between guanine and the bridging nitrogen are found at ±80° in AAF–dG, and at 120° and –90° for AF–dG. Overall, the fluorene–dG linkages in AF–dG and AAF–dG adducts have significantly different equilibrium structures and torsional flexibilities. These differences may be contributing factors for the observed disparity in mutagenic effects of these adducts.Electronic Supplementary Material: Supplementary material is available in the online version of this article at Acknowledgements. This work was supported by the NSF REU grant no. CHE-0243825 to Loyola University Chicago. We thank to Tom Ellenberger and Shuchismita Dutta for providing us with their results prior to publication.