钴-4-(5-氯-2-吡啶偶氮)-1,3-二氨基苯-Triton X-100体系的析相富集及痕量钴的光度测定

本文研究了TritonX-100在浊点条件下对钴-4-(5-氯-2-吡啶偶氮)-1,3-二氨基苯(5-Cl-PADAB)络合物的析相条件,在pH4.0～6.0介质中,将胶束溶液加热到92±1℃,保持40min,络合物即被TritonX-100相富集。富集液在575nm测定吸光度,钴含量在0～4μg/5ml范围内服从比尔定律,干扰离子可在TritonX-100析相液中加入H_2SO_4消除。拟定的方法灵敏、简捷,已用于不经分离直接测定人发及自来水中痕量钴。

New process for the preparation of 3,5-dihydroxy-1-pentylbenzene

A new process for the preparation of 3,5-dihydroxy-1-pentylbenzene, which is used as medicinal intermediate and raw material for the synthesis of HIV restrainer, is proposed in this paper. Technical 3,5-dimethoxybenzoic acid reacted with lithium hydride to form a salt (I) which acylated n-butyllithium directly to give 1-(3,5-dimethoxyphenyl)-1-pentanone (II) in 85.06% yield. Then (II) was reduced through a Wolff-K-Huangminglong reaction at 210 degrees C to give 3,5-dimethoxy-1-pentylbenzene (III). Finally, (III) refluxed with melt pyridine hydrochloride at 200 degrees C for 2 h to afford the target product 3,5-dihydroxy-1-pentylbenzene (IV). The total yield of (IV) amounted to 61.50% and its mass percentage was 98.22%. The products were characterized by means of IR, H-1-NMR, GC and HLPC-MS. The results indicated that this synthetic route was feasible, characterized by simple process and higher yield, and superior to the published ones.

The nature of the interaction between polyaniline and 2,5-dimercapto-1,3,4-thiadiazole in electrochemical redox processes

The interaction between polyaniline (PAn) and 2,5-dimercapto-1,3,4-thiadiazole (DMcT) was investigated by means of cyclic voltammetry and UV-visible spectroscopy. The results show that the polymerization-depolymerization reaction of DMcT or its dilithium salt Li(2)DMcT is a kinetically quasi-reversible process. PAn exhibits very weak electrochemical activity in neutral propylene carbonate. After doping with protonic acid, such as hydrochloric acid or maleic acid etc., however, it shows an extensively enhanced electroactivity. For the complex system, PAn-DMcT or PAn-Li(2)DMcT, polyaniline has no catalytic activity for the electrochemical polymerization-depolymerization reaction of DMcT or DMcT(2-). Instead, the enhancement of the electrochemical redox activity of PAn-DMcT system compared with that of PAn, DMcT, Li(2)DMcT, and PAn-Li(2)DMcT comes from the protonic doping of PAn by DMcT.

Investigation of the electrocatalytic effect of polyaniline on the redox reaction of 2,5-dimercapto-1,3,4-thiadiazole by cyclic voltammetry

Electrochemical polymerized polyaniline(PAn) film electrode was used to investigate the electrocatalytic effect of PAn on the electrochemical redox reaction of 2,5-dimercapto-1,3,4-thiadiazole (DMcT), PAn film electrode was electrochemically treated or immersed in DMcT solution before it was scanned in 1.0 mol/L HCl electrolyte. The cyclic voltammograms of PAn film electrode in 1.0 mol/L HCl solution changed with the above treatment, implying the electrocatalytic effect of PAn on the redox reaction of DMcT, The formation of electron-donor-acceptor adducts through the interaction between thiol or disulfide groups of DMcT and amine or imine groups of PAn during the treatment was probably the reason of the catalysis, The electrochemical properties of the adduct were different from those of PAn and DMcT, The adduct possessed a higher electrochemical activity and a better electrochemical reversibility than DMcT or PAn used alone.

Soluble 2,5-dimercapto-1,3,4-thiadiazole/poly(o-toluidine) electroactive composite

A poly(o-toluidine) (POT)/2,5-dimercapto-1,3,4-thiadiazole (DMcT) composite was prepared. When POT and DMcT are mixed in a proper solvent, POT in a medium-oxidation state is reduced, and DMcT in turn is oxidized to its soluble dimer when the molar ratio of DMcT to POT is higher than 0.5. Therefore, the composite was soluble in organic solvents such as tetrahydrofuran (THF), dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP) and exhibited very high electroactivity, two orders of magnitude higher than that of pure POT and three orders of magnitude higher than that of pure DMcT. Molecular-level contact between POT and DMcT is the reason for the improved catalytic effect of POT on DMcT, compared to that of polyaniline on DMcT. (C) 1999 The Electrochemical Society. S0013-4651(98)08-059-8. All rights reserved.

The antioxidant activity of 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-di-sulfanimide)-chitosan

Chitosan (CS) with two different molecular weights was modified by reacting with 4-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride or 2-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride to give new 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-di-sulfanimide)-chitosan (2-HCBSAHCS, 2-HCBSALCS, 4-HCBSAHCS, 4-HCBSALCS). The structure of the derivatives was characterized by FT-IR and C-13 NMR spectroscopy. The antioxidant activities of the derivatives were investigated employing various established systems, such as hydroxyl radical ((OH)-O-center dot)/superoxide anion (O-2(radical anion)) scavenging/reducing power and chelating activity. All the derivatives showed stronger scavenging activity on hydroxyl radical than chitosan and ascorbic acid (Vc), and IC50 of 4-HCBSAHCS, 4-HCBSALCS, 2-HCBSAHCS and 2-HCBSALCS was 0.334, 0.302, 0.442, 0.346 mg/mL, respectively. The inhibitory activities of the derivatives toward superoxide radical by the PMS-NADH system were strong. The results showed that the superoxide radical scavenging effect of 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-disulfanimide)-chitosan was higher than chitosan. The derivatives had obviously reducing power and slight chelating activity. The data obtained in in vitro models clearly establish the antioxidant potency of 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-disulfanimide)-chitosan. (C) 2007 Elsevier Masson SAS. All rights reserved.

Nickel(II) and copper(II) complexes containing 2-(2-(5-substitued isoxazol-3-yl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione ligands: Synthesis, spectral and thermal characterizations

Two new hydrazone chelating ligands, 2-(2-(5-methylisoxazol-3-yl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione (HL1) and 2-(2-(5-tert-butylisoxazol-3-yl)hydrazono)-5,5-dimethylcyclohexane- 1,3-dione (HL2), and their nickel(II) and copper(II) complexes were synthesized using the procedure of diazotization, coupling and metallization. Their structures were postulated based on elemental analysis, H-1 NMR, ESI-MS, FT-IR spectra and UV-vis electronic absorption spectra. Smooth films of these complexes on K9 glass substrates were prepared using spin-coating and their absorption properties were evaluated. The thermal properties of the metal(II) complexes were investigated by thermogravimetry (TG) and differential thermogravimetry (DTG). Different thermodynamic and kinetic parameters namely activation energy (E

Metal dependent control of cis-/trans-1,4 regioselectivity in 1,3-butadiene polymerization catalyzed by transition metal complexes supported by 2,6-bis[1-(iminophenyl)ethyl]pyridine

Fe(III), Cr(III), Fe(II), Co(II) and Ni(II) chloride complexes supported by 2,6-bis[1-(iminophenyl)ethyl]pyridine have been synthesized and characterized along with single crystal X-ray diffraction. These complexes, in combination with MAO, have been examined in butadiene polymerization. The catalytic activity and regioselectivity are strongly controlled by metal center and cocatalyst (MAO/Co ratio dependent in the case of Co(II) complex). The activity decreases in the order of Fe(III) > Co(II) > Cr(III) approximate to Ni (II) complexes, in consistent with the space around the metal center. Polybutadiene with different microstructure content, from high trans-1,4 units (88-95% for iron(III) and Cr(III)), medium trans-1,4 and cis-1,4 units (55% and 35%, respectively, for iron(II)) to high cis-1,4 units 79% for Co(II) and 97% for Ni(II) call be easily achieved by varying of the metal center.

Diacetatobis[2-(2-furyl)-1H-imidazo[4,5-f]-[1,10]phenanthroline]cadmium(II)

In the title complex, [Cd(C2H3O2)(2)(C17H10N4O)(2)], the central Cd-II ion (site symmetry 2) shows an uncommon eight-coordinate CdN4O4 coordination geometry arising from two N,N-chelating 2-(2-furyl)-1H-imidazo[4,5-f]-1,10-phenanthro-line molecules and two O, O-bidentate acetate anions.

catena-Poly[[[2-(2-furyl)-1H-imidazo[4,5-f][1,10]phenanthroline]zinc(II)]-mu-benzene-1,2-dicarboxylato]

In the title compound, [Zn(C8H4O4)(C17H10N4O)](n), the Zn-II atom is five-coordinated by two N atoms from the phenanthro-line-derived ligand and three O atoms from one bidentate and one monodentate benzene-1,2-dicarboxylate (1,2-BDC) dianions in a distorted trigonal-bipyramidal geometry. The Zn-II atoms are bridged by the 1,2-BDC ligands to form a single-chain structure. Neighboring chains interact through pi-pi interactions, leading to a two-dimensional network.

Novel highly selective anion chemosensors based on 2,5-bis(2-hydroxyphenyl)-1,3,4-oxadiazole

2-(2-Hydroxyphenyl)-5-phenyl-1,3,4-oxadiazole 1 and 2,5-bis(2-hydroxyphenyl)-1,3,4-oxadiazole 2 were used as anion fluorescent and colorimetric chemosensors with high selectivity for H2PO4- and F- over Cl-, while 2 can even distinguish H2PO4- from F-. (C) 2002 Elsevier Science Ltd. All rights reserved.

镧系金属杂—2,3,4,5—四苯基环戊二烯环状化合物的合成及其表征

二苯乙炔和金属锂在乙醚中反应得到1,4-二锂四苯基丁二烯,再与无水氧化希土反应得到了两种系金属条-2,3,4,5-四苯基环戊二烯环状化合物。通过元素分析、红外光谱、核磁共振谱、热失重及电子能谱的分析,对所合成的化合物进行了表征;并对化合物的水解产物作了红外光谱、质谱和核磁共振谱分析,确认下列两种化合物的存在:

1，3，5-三氯苯在土壤沉积物水体系中的吸附过程研究

以自然土壤、沉积物样品为研究对象，研究了1，3，5-三氯苯在样品上的等温吸附过程。结果表明，线性模型和Freundlich模型能较好地拟合所有样品的等温线，而双区位反应模型(DRDM)适用范围有限。研究表明，三氯苯的吸附容量大小主要取决于样品中有机碳的含量，并且与不可提取态有机质和粘土矿物含量有一定的关系。以自然土壤、沉积物样品为研究对象，研究了1，3，5-三氯苯在样品上的等温吸附过程。结果表明，线性模型和Freundlich模型能较好地拟合所有样品的等温线，而双区位反应模型(DRDM)适用范围有限。研究表明，三氯苯的吸附容量大小主要取决于样品中有机碳的含量，并且与不可提取态有机质和粘土矿物含量有一定的关系。

Synthesis, characterization and crystal structure of a charge transfer salt based on 1.3-cyclopentadiene tetrabutylammoniumdodecamolybdosilicoate

A charge transfer salt, (Bu4N)(4) (C5H6)[(HSiMo11MoO40)-Mo-VI-O-V] has been photochemically synthesized from (Bu4N)(4)SiMo12O40 and 1.3-cyclopentadiene and Characterized, by elemental analysis, IR spectra, solid diffusion reflectance electronic spectra, CV and ESR. The X-ray crystal structure revealed that the title complex crystal data are as follows: triclinic, space group P (1) over bar, a = 14.347(3), b = 14.423(3), c = 27.158(5) Angstrom, alpha = 96.90(3), beta = 104.18(3), gamma = 98.20(3)degrees, V = 5322(2) Angstrom (3), Z = 2, M-r = 2855. 30, D-c = 1.782g.cm(-3), F(000) = 2860, R = 0.0719, wR = 0.198. The title compound is composed of 1.3-cyclopentadiene, four tetrabutylammonium and [(SiMo11MoO40)-Mo-VI-O-V](4-) anion.