4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-1,3,5-triazine modified carbon paste electrode for trace Cu(Ⅱ) determination by differential pulse volt-ammetry

A differential pulse voltammetric method was developed for the sensitive andselective determination of Cu(II) at 4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-l,3,5-triazine modifiedcarbon paste electrode in 0.05 mol/L KHC_8H_4O_4 solution (pH = 4.02). The oxidation peak of Cu(II)was observed at 0.065 V(vs Ag/AgCl) by scanning the potential in positive direction. The analysisprocedure consisted of an open circuit accumulation step in stirred sample solution. It was followedby medium exchange to a clean solution and subsequently an anodic potential scan was affected toobtain the voltammetric peak. The current was proportional to the concentration of the Cu(II) ion ina range of 1 X 10^(-7) -1 X 10^(-4) mol/L for 6 min accumulation; the most of metal ions did notinterfere with the determination. The developed method was applied to Cu (II) determination incoal-ash sample, the results agreed with that of atomic adsorption spectroscopy (AAS).

Syntheses, Structures and Properties of Four Manganese Coordination Polymers Derived from 4-Amino-3,5- bis（imidazol-1 -ylmethyl）-1,2,4-triazole

The reaction of 4-amino-3,5-bis（imidazol-l-ylmethyl）-1,2,4-triazole （abit） and manganese（Ⅱ） salts yields four coordination polymers {[Mn（abit）3]（C104）z}n （1）, {[Mn（abit）3]（PF6）2},, （2）, [Mn（abit）（dca）2（H2O）2],, （3a） and [Mn（abit）（dca）2（H2O）2]n （3b）. Compounds 1 and 2 are one-dimensional triple-stranded chain. Compounds 3a and 3b are polymorphous and construct one-dimensional single chain. The conformational analysis is performed. The thermal properties have been investigated.

Two New Iron Coordination Polymers Based on Fe-pyta Chains Incorporating Pyridine-2,4,6-tricarboxylate

Reaction of FeCIz＇6H20, pyridine-2,4,6-tricarboxylic acid（H3pyta） and NaOH in the hydrothermal system at 185 ℃ resulted in the formation of 1D coordination polymer[Fe（Hpyta）（H2O）2]（1） based on Fe-Hpyta chains. When the abpt[abpt=-4-amino-3,5-bis（4-pyridyl）-l,2,4-triazole] ligand was employed in the reaction system, a 3D supramolecular porous network （H2bpt）[Fe（pyta）（H2O）2]·4H2O（2） was obtained. The framework was constructed with negative （Fe-pyta） chains and the positive H3bpt^＋ in situ, formed from the abpt reagent, to form 1D channels filled with guest water molecules via hydrogen-bonds. X-Ray diffraction crystal structure analysis shows that complex 1 crystallized in the monoclinic system, space group C2/c, a=1.1490（5） nm, b=0.9008（4） nm, c=1.0058（5） nm, B=107.254（9）°, V=0.9942（8） nm3, Z=4; and complex 2 crystallizes in the triclinic system, space group P1 with a=0.90392（11） nm, b=0.96027（11 ） nm, c=1.55540（18） nm, a=73.558（2）°,B= 86.126（2）°,r= 68.745（2）°, V=1.2059（2） nm^3 and Z=2.

Two New Diarylheptanoids from the Rhizomes of Zingiber officinale

Two new diaryheptanoids, (5S)-5-acetoxy-1,7-bis(4-hydroxy-3-methoxyphenyl)-3- heptanone (1) and (3S,5S)-3,5-diacetoxy-1,7-bis(4-hydroxy-3-methoxyphenyl)heptane (2) were isolated from the rhizomes of Zingiber officinale. Their structures were elucidated by spectral methods.