- Establishment of the light-absorption ratio variation approach and application to determination of CO(II) in the ng ml-1 level and novel characterization of Co(II) and Zn(II) complexes with 1,5-di(2-hydroxy-5- sulfophenyl)-3-cyanoformazan
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The light-absorption ratio variation approach (LARVA) has been established and applied to the determination of Co on the ng ml-1 level with 1, 5-di(2-hydroxy-5-sulfophenyl)-3-cyanoformazan (DSPCF) at pH 9.33. Competitive replacement complexatio
- Gao, Hong-Wen,Wang, Hong-Yan,Zhang, Sheng-Yi,Zhao, Jian-Fu
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- Digital logic circuit based on a single molecular system of salicylidene schiff base
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The salicylidene Schiff base N-3,5-dichloro-salicylidene-(S)-α- phenylethylamine (SPEA) has been synthesized and characterized. Stimulated by one optical input (UV light) and two chemical inputs (OH- and Zn 2+), SPEA undergoes reactions of photochemistry, deprotonation, and complexation. Tailing these reactions by means of the UV-vis absorption spectra and fluorescence spectra, two obvious optical outputs, an absorption band at 323 nm and a fluorescent emission peak at 460 nm, have been obtained. On the basis of encoding binary digits in these inputs and outputs applying positive logic conventions, one monomolecular circuit, which integrates one OR, two NOT, and four AND gates, has been achieved.
- Zhao, Liyan,Sui, Dan,Chai, Jia,Wang, Yue,Jiang, Shimei
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- Stability of ZnO Particles in Aqueous Suspensions under UV Illumination
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The effect of UV illumination on the stability of ZnO particles in aqueous suspensions is investigated.The quantity of ZnO photodecomposed has been determined by measuring polarographically the resulting Zn(II) concentration in solution at different irrad
- Domenech, J.,Prieto, A.
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- Enhanced photochromism of 1,2-dithienylcyclopentene complexes with metal ion
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A new bis(5-pyridyl-2-methylthien-3-yl)cyclopentene, as a photochromic bridging ligand, has been synthesized and the photocyclization quantum yield was found to increase in the presence of a metal ion.
- Qin, Bing,Yao, Rongxia,Zhao, Xueli,Tian, He
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- Copper(II) Complexes of Substitued Macrobicyclic Hexaamines: Combined Trigonal and Tetragonal Distortions
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The hexaamine complexes [M{(NH3)2sar}](4+) and [M{(NMe3)2sar}](4+) (M =Cu(II), Zn(II); sar = 3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane) have been synthetized and characterized both spectroscopically and structurally. X-ray crystal structural analyses of [Cu{(NH3)2sar}](NO3)4*H2O (monoclinic, P21, a 12.311(3) ?, b 12.338(4) ?, c 8.574 ?, β 93.91(3)°, Z = 2), [Zn{(NH3)2sar}](NO3)4*H2O (monoclinic, P21,a 12.365(4) ?, b 12.396(7) ?, c 8.587(4) ?, β 94.13(3)°, Z = 2), [Cu{(NMe3)2sar}](ClO4)4 (hexagonal P6-2C, a 8.689(2) ?, c 27.927(2) ?, Z = 2), and [Zn{(NMe3)2sar}](ClO4)4 (hexagonal,P6-2C, a 8.669(5) ?, c 27.997 ?, Z = 2) are reported. Visible-near-infrared absorption, circular dichroism, magnetic circular dichroism, and electron paramagnetic resonance spectroscopic studies reveal distorted CuN6 chromophores. Trigonal distortions arise from steric requirements of the ligands, whereas tetragonal distortions result from Jahn-Teller coupling in the Cu(II) complexes. X-ray crystallographic studies of these copper(II) complexes revealed partially averaged ([Cu{(NH3)2sar}](4+)) and completely averaged ([Cu{(NMe3)2sar}](4+)) geometries as a result of both static disorder and dynamic processes throughout each lattice. Partial resolutions of [Cu{(NMe3)2sar}](4+) into its enantiomeric forms was achieved to give the first stable chiral molecule where Cu(II) is the stereogenic atom. In the absence of Jahn-Teller coupling characteristic of their Cu(II) relatives, the analogous Zn(II) complexes exhibited high-symmetry structures both in solution and in the solid state.
- Bernhardt, Paul V.,Bramley, Richard,Engelhardt, Lutz M.,Harrowfield, Jack M.,Hockless, David C. R.,et al.
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- Substitution effects in the A- and B-rings of the chlorin macrocycle on demetalation properties of zinc chlorophyll derivatives
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Effects of peripheral substituents in the A- and B-rings of the chlorin macrocycle on demetalation of zinc chlorophyll derivatives were examined. The demetalation rate constants of zinc 8-formyl-chlorin (1) were comparable to those of zinc 3-formyl-chlorin (2). Both 1 and 2 exhibited significantly slower demetalation kinetics than the corresponding zinc chlorin 3, which had no formyl group. Comparison of demetalation kinetics between zinc 3-ethyl-chlorin (3) and zinc 3-vinyl-chlorin (4) indicated that the substitution at the 3-position of the chlorin macrocycle from a vinyl to an ethyl group accelerated removal of the central zinc. Activation energies of demetalation of zinc chlorins 1, 2, and 5 possessing a formyl group in the A- or B-ring of the chlorin macrocycle were larger than those of zinc chlorins 3 and 4 lacking a formyl group. These results indicate that the formyl groups in the A- or B-ring provide tolerance to demetalation of chlorin molecules due to their electron-withdrawing effects.
- Hirai, Yuki,Sasaki, Shin-Ichi,Tamiaki, Hitoshi,Kashimura, Shigenori,Saga, Yoshitaka
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- Experimental and quantum-chemical studies of anabasine complexes with copper(II) and zinc(II) ions
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Anabasine copper(II) and zinc(II) complexes have been studied using experimental methods and quantum-chemical studies. Preferred coordination centers and possible structures of the complexes have been determined. It has been revealed, that the main coordi
- Bregier-Jarz?bowska, Romualda,Malczewska-Jaskó?a, Karolina,Jankowski, Wojciech,Jasiewicz, Beata,Hoffmann, Marcin,G?sowska, Anna,Jastrz?b, Renata
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- Spiropyrans and spirooxazines: 11. Complexation of photochromic 5-(1,3-benzothiazol-2-yl)-substituted 1,3-dihydrospiro[benzo[f]chromene-3,2-indole] with metal ions
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5-(1,3-Benzothiazol-2-yl)substituted 1,3-dihydrospiro[benzo[f]chromene-3,2-indole] forms intensely colored complexes with metal ions in acetone solution in the absence of irradiation. The composition and stability of the complexes were shown to depend on the nature of the metal ion. The molecular structure of the zinc complex was determined by X-ray diffraction. The complexes with diamagnetic ions display negative photochromism associated with their reversible dissociation induced by visible light.
- Rostovtseva,Chernyshev,Tkachev,Aldoshin,Voloshin,Metelitsa,Makarova,Minkin
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p. 677 - 682
(2015/11/27)
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- DEVICES FOR TREATMENT OF SKIN DISORDERS
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The present invention discloses a layer of fabrics having antibacterial/microbe-resistant properties that are designed for contacting with the human skin. The fabric layer can be disposed, directly or indirectly, onto a pillowcase, pillow, comforter, comforter cover, head support, bed cloth, sleeping bag, mattress, cushion, blanket, and garment.
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- Reactivity of metal oxides: Thermal and photochemical dissolution of MO and MFe2O4 (M=Ni, Co, Zn)
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Dissolution rates of NiO, CoO, ZnO, α-Fe2O3 and the corresponding ferrites in 0.1 mol dm-3 oxalic acid at pH 3.5 were measured at 70 °C. The dissolution of simple oxides proceeds through the formation of surface metal oxalate complexes, followed by the transfer of surface complexes (rate-determining step). At constant pH, oxalate concentration and temperature, the trend in the first-order rate constant for the transfer of the surface complexes (kMe; Me=Ni, Co, Zn, Fe) parallels that of water exchange in the dissolved metal ions (k-w). Thus, the most important factor determining the rates of dissolution of metal oxides is the lability of Me-O bonds, which is in turn defined by the electronic structure of the metal ion and its charge/radius ratio. UV (384 nm) irradiation does not increase significantly the dissolution rates of NiO, CoO and ZnO, whereas hematite is highly sensitive to UV light. For ferrites, the reactivity order is ZnFe2O4>CoFe2O4?NiFe2O4. Dissolution is congruent, with rates intermediate between those of the constituent oxides, Fe2O3 and MO (M=Co, Ni, Zn), reflecting the behavior of very thin leached layers with little Zn and Co, but appreciable amounts of Ni. The more robust Ni2+ labilizes less the corresponding ferrite. The correlation between log kM and log k-w is somewhat blurred and displaced to lower kM values. Fe(II), either photogenerated or added as salt, enhances the rate of Fe(III) phase transfer. A simple reaction mechanism is used to interpret the data.
- Garcia Rodenas, Luis A.,Blesa, Miguel A.,Morando, Pedro J.
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p. 2350 - 2358
(2009/05/30)
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- Dissociation kinetics of cobalt and zinc β-octabromo-meso-tetraphenyl- and β-octaethyl-meso-tetraphenylporphyrin complexes
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Kinetics of solvoprotolytic dissociation of zinc and cobalt porphyrin complexes with a porphyrin macrocycle distorted to different extents (β-octaethyl-meso-tetraphenylporphyrin and β-octabromo-meso- tetraphenylporphyrin) have been studied in binary proton-donating solvents. The main factor decreasing the stability of the porphyrin complexes is the distortion of the planar structure of the macrocycle. The reactivity of the cobalt porphyrins is governed by both structural and electronic effects.
- Pukhovskaya,Guseva,Semeikin,Golubchikov
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p. 190 - 193
(2008/10/09)
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- Calorimetric studies on leaching of mechanically activated sphalerite in FeCl3 solution
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The thermal behaviors of the leaching of mechanically activated sphalerite were investigated for the first time by calorimetry. The specific granulometric surface area and the structural disorder sphalerite were also analyzed by X-ray diffraction laser particle size analyzer and X-ray powder diffraction (XRD) analysis, respectively. A new method to measure the mechanically activated storage energy of minerals was proposed by designing a thermochemical cycle that made mechanically activated and non-activated mineral reaching the same final state while leaching in FeCl3 solution. The results indicate that the mechanically activated storage energy of sphalerite rises with the increased grinding time and is closely related to the lattice distortions and crystallite sizes. The calorimetric results of the products from sieved in water or ethanol medium and the products from 2 h treatment of mechanically activated sphalerite under pure argon (99.99 vol.%) at different temperatures indicate that the mechanically activated storage energy of sphalerite is caused mainly by changes of the crystal structure, and the reactivity of mechanically activated sphalerite is difficult to lose.
- Xiao, Zhongliang,Chen, Qiyuan,Yin, Zhoulan,Hu, Huiping,Zhang, Pingmin
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- Computer simulation study of patterns of copper and silver dendrites grown from aqueous solution in high magnetic field
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The magnetic field effects (MFEs) on the patterns and yields of silver and copper dendrites generated from Cu2+/Zn and Ag+/Cu liquid-solid redox reactions are simulated with the aid of a biased random walk model. In the present model, multi-particles are generated to represent metal ions, and their trajectories walk randomly with superimposed drifts. Comparing the simulation patterns and yields with the experimental ones, it is confirmed that the convection of solution induced by the magnetic force is responsible for the observed MFEs on the dendrites in a high magnetic field gradient (ca. 400T2m-1).
- Duan,Fujiwara,Tanimoto
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p. 2461 - 2467
(2007/10/03)
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- Kinetic and equilibrium studies of the acid dissociation of the zinc(II) complexes of N,N'-dialkyl-1,10-phenanthroline-2,9-dimethanamine ligands
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The complexation property and the acid dissociation kinetics of the zinc(II) complexes of N,N'-dialkyi-1, 10-phenanthroline-2,9-dimethanamine ligands have been studied using pH-metric and a stopped-flow spectrophotometer. In 3.3x10-3 -1.2x10-2 mol dm-3 HCl (I=105 mol dm-3+NaCl), the dissociation rate follows the law k(abs)= kK[H+]. The acid dissociation can be rationalized in terms of four-step kinetic process involving two rapid pre-equilibrium protonations and rate-determining cleavage of the Zn(II)-N(phenanthroline) bond. Steric effects on the stability of complexes and on the kinetic process have also been discussed.
- Sun,Lin,Zhou,Zhao,Zhu,Su,Chen
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p. 430 - 433
(2007/10/03)
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- Oxidation of Zn-Cu Alloy with Iodine in Nonaqueous Media
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Dissolution of Zn-Cu alloy under the action of iodine in a donor-acceptor solvent (acetonitrile, dimethylformamide) was studied. Schemes of the processes were proposed, and the kinetic and thermodynamic parameters of some reaction stages were estimated.
- Modinova,Sergeeva,Maslennikov
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p. 1539 - 1542
(2007/10/03)
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- Effect of high magnetic field on the silver deposition from its aqueous solution
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The effects of a high gradient magnetic field on the Ag+/Cu liquid-solid redox reaction were studied. A copper wire was placed on a sheet of chromatography paper wet with silver nitrate aqueous solution. At zero field silver dendrites grew uniformly around the wire. In the presence of a gradient magnetic field (ca. 380 T2m-1), the dendritic pattern changed drastically. The yield of silver metal increased by about 45%. These results are attributable to the convection of aqueous solution on the surface of the paper which is induced by the magnetic force on the paramagnetic copper ions generated in the reaction.
- Tanimoto,Katsuki,Yano,Watanabe
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p. 7359 - 7363
(2007/10/03)
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- Mixed- ligand Complex Formation of Cobalt(II), Nickel(II) and Zinc(II) with N-Benzenesulphonyl-l-cysteine as Primary Ligand and Bipyridine, Ethylenediamine and Glycinate as Secondary Ligands
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Equilibrium study on the complex formation of M2+ ions (M = Co, Ni and Zn) with N-benzenesulphonyl-l-cysteine (NBSCH2) in the presence of bipyridine, ethylenediamine, glycinate (B) indicates the formation of mixed-ligand complexes of the types M(NBSC)(B), M(H-I NBSC)(B) and M(H-I NBSC)(OH), together with binary M(NBSC) and M(B) complexes. Formation constants of the complexes have been determined by potentiometric method at 25±0.1° in 50% (v/v) ethanol-water medium at a constant ionic strength, I=0.2 M (NaNO3). Stability of the complexes has been correlated with the modes of coordination of NBSC, basicity of the B ligands and π-electron delocalisation in the metal-ligands bonds.
- Mukherjee,Ghosh
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- Photocatalytic reduction of nitrite and nitrate ions over oxide (ZnO, ZrO2 and Fe2O3) semiconductors
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The photocatalytic reduction of nitrite and nitrate ions to ammonia has been studied over ZnO, ZrO2, Fe2O3 and Fe3O4 oxide semiconductors. Many parameters such as the position of the conduction band edge of the semiconductor, the metal-semiconductor junction, light absorption capacity of the semiconductor, adsorption of the reagent species and pH of the medium used influence the yield of ammonia and hence one can not a priori predict the relative activity of these systems on the basis of band edges alone. The resulting photoactivity is a balance of the above said factors some of which play contrasting roles.
- Ranjit,Varadarajan,Viswanathan
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p. 177 - 181
(2007/10/03)
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- Reactive compounds containing perfluorocyclobutane rings
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Novel compounds have at least one perfluorocyclobutane ring and at least two functional groups suitable for forming condensation polymers. Preferably the compounds have a structures represented by Formula II: STR1 wherein R and R' independently represent optionally inertly substituted groups; X and X' represent any molecular structures which link R and R' with the perfluorocyclobutane ring; n and n' are the number of G and G' groups, respectively; and G and G' independently represent any reactive functional groups or any groups convertible into reactive functional groups. The compound are preferably prepared by a process of thermally dimerizing trifluorovinyl compound to form a compounds of Formula I wherein G represents G or G' in Formula II; X represents X or X' of Formual II; and n represents n or n' of Formula II, to form a compound having a perfluorocyclobutane group.
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- Coordination properties of sterically hindered porphyrins and metal porphyrins
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The detailed mechanism of the coordination reactions of porphyrins has been established by a study of the kinetics of complex formation of sterically hindered porphyrins with copper, zinc, and cadmium acetates in pyridine and in dimethylformamide, and also of the kinetics of the solvoprotolytic dissociation of the zinc and manganese complexes.The role of spatial shielding in the formation and dissociation reactions of sterically hindered porphyrins is discussed.
- Golubchikov, O. A.,Lomova, T. N.,Kuvshinova, E. M.,Korovina, S. G.,Klyueva, M. E.,et al.
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p. 188 - 192
(2007/10/02)
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- A Raman spectral study of the equilibria of zinc bromide complexes in DMSO solutions
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Using Raman spectroscopy, the stepwise formation of zinc bromide complexes in dimethylsulfoxide (DMSO) solution has been investigated.The presence of four different zinc bromide complexes is suggested and their Raman spectra have been extracted.The formation constant of each reaction has been estimated by the application of factor analysis to the spectra.The usual methods of factor analysis have been extended by the introduction of constraints imposed by the equilibria.Key words: zinc bromide complexes, solvation in DMSO, Raman spectroscopy, factor analysis.
- Heumen, Jeff van,Ozeki, Toru,Irish, Donald E.
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p. 2030 - 2036
(2007/10/02)
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- Mechanism of the Current Doubling Effect. I. The ZnO Photoanode in Aqueous Solution of Sodium Formate
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Current doubling mechanism of the photoanodic reaction of sodium formate at the ZnO electrode is re-examined.Quantitative analysis of the reaction products revealed that ZnO electrode corroded during the current doubling reaction, which has not been previously reported.However, zinc ions were formed with about 50percent of current efficiency.Carbon dioxide, instead of oxygen, was formed during the reaction.These experimental observations strongly suggested mechanism proposed by earlier workers were incorrect.A new mechanism is proposed.
- Fujishima, Akira,Kato, Tamihiko,Maekawa, Etsuro,Honda, Kenichi
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p. 1671 - 1674
(2007/10/02)
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