Synthesis and electrochemical properties of a series of novel tetra(4-benzoyl)phenoxyphthalocyanine derivatives

A novel phthalocyanine,2,9(10),16(17),23(24)-tetra(4-benzoyl)phenoxyphthalocyanine,and its complexes with Zn(II),Cu(II),Co(II),and Ni(II) have been synthesized and characterized by a combination of elemental analysis,IR,1 H NMR,UV-vis spectroscopy and mass spectrometry.All of the materials are very soluble in common organic solvents such as dichloromethane,chloroform,tetrahydrofuran,N,N-dimethylformamide and dimethyl sulfoxide.The Q band wavelengths of the complexes decrease in the order:Zn > Cu > Ni > Co.Redox processes were observed at 1.06,0.74,0.51 and 0.98 V for the free phthalocyanine,at 0.72 and 1.04 V for the Co(II) complex,at 1.24,0.77,0.24,0.61 and 0.91 V for the Cu(II) complex,and at 0.74 and 1.20 V for the Ni(II) complex.The cyclic voltammograms of the phthalocyanine ring of the four species are similar,with reduction and oxidation couples each involving a one-electron transfer process.     

Synthesis and Characterization of Self-Assembled V2O5 Mesostructures Intercalated by Polyaniline

A new nanocomposite of vanadium pentoxide (V2O5) and polyaniline (PANI) were synthesized by in situ oxidative polymerization/intercalation on V2O5 powder at room temperature. The reaction was facile and topotactic, forming polyaniline as the emeraldine salt. It was indicated that V2O5 itself can catalyze the oxidative polymerization of aniline and that layered structure could make aniline intercalate into the V2O5 framework. It makes the in situ polymerization feasible to occur in the layer of V2O5 structure. XRD results showed PANI/V2O5 nanocomposite possessed lamellar mesostructure, which was determined by an X-ray diffraction peak at 6.5° and SEM photograph. And FT-IR spectrum suggested that there was interaction between PANI and V2O5. The hybrid had better thermal stability in N2 and air ambience.     

V Centers and Hole-Photostimulated Luminescence of BaFCl Crystal

V centers (hole centers) and hole-photostimulated luminescence of BaFCl crystal are reported for the first time. The absorption bands of V1, V2 and V3 centers are peaking at 205, 238 and 355 nm respectively. V2 center creation by X-irradiation and decay during photostimulated luminescence process are synchronousl with that of F center. This indicates that V centers play the same roles as F centers in X-ray storage and photostimulated luminescence processes.     

钒催化剂选择性氧化乳酸乙酯制丙酮酸乙酯

The structure and surface acidity of vanadium oxide supported on α-Al₂O₃、TiO₂、SiO₂ have been studied by XRD、IR、TPR and adsorption microcalorimetry. The catalytic performance of the catalysts for selective oxidation of ethyl lactate to ethyl pyruvate was determined in a continuous flow fix-bed reactor. The results showed that the dispersion of vanadium oxide on the supports weakened the V=O bond and actived the terminal oxygen, which increased the reaction activity. On the otherhand, The surface acidity is harmful to the selectivity of ethyl pyruvate. V/α-Al₂O₃ exhibited a lower conversion since its dispersion is low. The low selectivity on V/SiO₂ is due to its fairly strong surface acidity. Addition of K⁺ weakened the surface acidty and enhanced selectivity of V/SiO₂. V/TiO₂ exhibited the best activity and selectivity among the catalysts studied because of its weak surface activity. The conversion of ethyl lactate and selectivity to ethyl pyruvate are 97% and 81%, respectively, over the V/TiO₂ catalyst at 473K.     

The study of preconcentration and separation of vanadium(V) using microcrystalline triphenylmethane loaded with crystal violet and the determination of vanadium(V) in water samples by spectrophotometry

The paper describes a novel method for vanadium(V) preconcentration using microcrystalline triphenylmethane loaded with crystal violet (CV) prior to the determination by spectrophotometry. The effects of different parameters, such as the amounts of crystal violet and triphenylmethane, acidity, stirring time, various salts and metal ions etc on the enrichment yield of V(V) have been investigated to select the experimental conditions. V(V) can be completely separated from Cd(II), Pb(II), Mn(II), Co(II), Cu(II), Fe(III), Ni(II), Al(III), Zn(II) and Hg(II) by controlling acidity. Under the optimum conditions, V(V) can be totally adsorbed on the surface of microcrystalline triphenylmethane. The possible reaction mechanism of the enrichment of V(V) is discussed in detail in this paper. The detection limit of this proposed method is 0.023 μg L⁻¹ with the preconcentration factor of 200. The recovery is in a range of 96.0–104%. The proposed method has been successfully applied to the determination of trace vanadium in various water samples with satisfactory results.     

RECTIFYING EFFECT OF POLYANILINE(PANI)/N-TYPE POROUS SILICONE HETEROJUNCTION*

Heterojunctions between polyaniline (PANI) and n-type porous silicon (PS), Al/PS-PANI/Au cell,were fabricated, and the rectifying parameters of this heterojunction diode were measured as a function of thepreparation conditions of PANI and PS, the electronic structure of PANI as well as cell structure. Therectifying parameters of Al/PS-PANI/Au cell were determined to be γ= 1 .8×10~1～ 1 .0×10~5 for the rectifyingratio at 3V, n = 3 ～12 for the ideal factor,j_0 = 8.0×10~(-5)～5.6×10~(-2) mA/cm~2 for the reversed saturated currentdensity, and φ_b = 0.67～ 0.83 V for the barrier height, respectively. The best rectifying heterojunction diodemade between PANI and n-type PS with higher rectifying factor (γ= 1 .0×10~5 at 3V ), output current (>1500mA/cm~2 at 3V) and lower ideal factor (n = 3.3) was obtained by preventing the oxidation of PS beforeevaporating Al electrode.     

STUDY OF ELECTROCHEMISTRY OF TETRANUCLEAR MOLYB-DENUM CLUSTER COMPOUND [Mo_4S_4(μ-dtp)_2(dtp)_4]

<正> The electrochemical behavior of tetranuclear molybdenum cluster [Mo4S4 (μ-dtp)2 (dtp)43 (1) (dtp = S2P (OEt)2) has been investigated by cyclic voltammetry, potentiotatic polarization measurement, controlled potential coulometry and pulse polarography. It is demonstrated that the compound undergoes two consecutive near reversible one-electron reductions at 0. 01V and -0. 77V , respectively and a near reversible one-electron oxidation at 1. 01V with scan rates from 25mV/sec to 1V/sec in cyclic voltammetric measurements. The cluster compound displays three redox processes, indicating its high structural stability.     

果茶中展青霉素含量的高效液相色谱测定

An HPLC procedure is described in this paper for the determination of patulin in nectar. The method con-sists of solvent extraction and chromatographic separation,The conditions of HPLC were column; Zorbax-C_8( 5μm) at 35℃; mobile phase :AcCN/water(5/95,V/V); and detector UV275nm. The detection limit was0. 1μg/mL,the linear range was 0.5～2. 5μg and average recovery was 96.54±2.27%.     

Study on electrode process of myoglobin at a polymerized Toluidine Blue film electrode

This paper reports the use of an electrochemically polymerized Toluidine Blue (TB) filmelectrode.The film on platinum electrode surface was analyzed with ESCA.The heterogeneouselectron transfer processes of myoglobin at the polymerized TB film electrode have been investigatedusing in situ UV-visible spectroelectrochemistry.The formal potential(E°′)and electron transfernumber(n)of myoglobin were calculated as E°′=0.045 V(vs.NHE)and n=0.99.The exhaustivereduction and oxidation electrolyses are achieved in 130 s and 110 s respectively,during a potential stepbetween-0.4 V and+0.4 V.A formal heterogeneous electron transfer rate constant(ksh)of 1.09×10~(-4) cm/s and a transfer coefficient(α)of 0.47 were obtained by cyclic voltabsorptometry,whichindicated that myoglobin underwent a quasi-reversible electrode process at the polymerized TB filmelectrode.     

Extraction-spectrophotometric study on the vanadium(V)-2,3-dihydroxynaphthalene — iodonitrotetrazolium chloride — water — chloroform system and its analytical application

The formation of a new ternary ion-associate complex of vanadium(V) with 2,3-dihydroxynaphthalene and iodonitrotetrazolium chloride with a composition ratio of 1:2:1 is reported. The complex is quantitatively extracted from water into chloroform. The molar absorptivity (ɛ) of the extract at λ _max=340 nm is 2.5 × 10⁴ dm³/mol cm, and Beer’s law is obeyed for concentrations ranging from 0.1 to 0.9 μg/cm³ V(V). The following constants are determined: the extraction constant, the association constant, the distribution constant, and the recovery factor. The effects of foreign ions and reagents are studied. A selective and sensitive method is developed for determination of vanadium in steels.