Electroanalysis and simultaneous determination of dopamine and epinephrine at poly(isonicotinic acid)-modified carbon paste electrode in the presence of ascorbic acid

A carbon paste electrode modified with electropolymerized fills of isonicotinic acid was developed. The modified electrode shows excellent electrocatalytic activity toward the oxidation of both dopamine （DA） and epinephrine （EP）. Separation of the reduction peak potentials for dopamine and epinephrine was about 357 mV in pH 5.3 phosphate buffer solution （PBS） and the character was used for the detection DA and EP simultaneously. The peak currents increase linearly with DA and EP concentration over the range of 8.0×10^-5 to 7.0×10^-4 mol/L and 5.0×10^-6 to 1.0×10^-4 mol/L with detection limits of 2×10^-5 and 1×10^-6 mol/L, respectively. The interference studies showed that the modified electrode exhibits excellent selectivity in the presence of large excess of ascorbic acid （AA）.

Synthesis, Structure and Fluorescence Properties of Tb(Ⅲ) Complex with Isonicotinic Acid and Biphenyl-2,2′-Dicarboxylic Acid

Terbium perchlorate reacted with isonicotinic acid （Hpya） and biphenyl-2,2＇-dicarboxylic acid （H2dpa） under hydrothermal condition, a new ternary terbium complex [ Tb （pya） （dpa） （H2O） n （ 1 ） was synthesized. The structure of the ternary complex was determined by X-ray single crystal diffraction and characterized by elemental analysis, fluorescence measurement. The fluorescence spectrum shows the title complex emits strong green light. The crystal data for the com- plex： monoclinic, P21/n space group, a =0.8908（5）nm, b = 1.0569（6）nm, c =2.0969（11）nm, β = 98.446（8）°, V = 1.9528（18） nm^3, Z = 4, R = 0.0241, wR2 = 0.0534. The center Tb3＋ ion is eight coordinated. The coordination polyhedron around Tb3 ＋ ion can be described as a distorted square antiprism. The complex forms an infinite one-dimenand sional alternating chain polymer by bridging carboxyl groups of pyadpa.

Synthesis and Crystal Structure of a New Silver(I) Isonicotinate Coordination Polymer:[(Ag_3L_2)(ClO_4)]_n(HL=Isonicotinic Acid)

The title complex [(Ag3L2)(ClO4)]n 1, where HL = isonicotinic acid, has been prepared from the reaction of isonicotinic acid with AgClO4?H2O at room temperature and its struc- ture was determined by single-crystal X-ray diffraction. The crystal of 1 is of triclinic, space group P1 with a = 8.429(3), b = 10.694(4), c = 10.840(4) ?, α = 119.063(4), β = 100.474(5), γ = 99.901(5)°, V = 800.4(5) ?3, Mr = 1334.53, Dc = 2.769 g/cm3, Z = 2, μ(MoKα) = 3.848 mm-1, F(000) = 632, R = 0.0250 and wR = 0.0582 for 2872 observed reflections with I > 2σ(I). Complex 1 is a two-dimensional network consisting of adjacent one-dimensional chains through Ag–Ag inter- actions.

Synthesis and Crystal Structure of a New Chain Coordination Polymer [Cu(inio)_2(H_2O)]_∞(Inio = Isonicotinic Acid N-Oxide)

A new Cu(Ⅱ) coordination polymer [Cu(inio)2(H2O)] (inio = isonicotinic acid N-oxide) with chemical formula C12H10CuN2O7 was prepared and its crystal structure has been determined by X-ray analysis. The complex crystallizes in the monoclinic system, space group C2/c with a = 12.455(3), b = 6.202(1), c = 16.555(3) ? b = 106.776(3), V = 1224.3(4) 3, Z = 4, Mr = 357.76, Dc =1.941 g/cm3, m(MoKa) = 1.827 mm-1, F(000) = 724, R = 0.0601 and wR = 0.1417 for 908 observed reflections (I > 2s(I)). The Cu(Ⅱ) atom is coordinated by an elongated square pyramid geometry. The deprotonated isonicotinic acid N-oxides form a double-bridge between each pair of Cu(Ⅱ) ions in trans form through two oxygen atoms from the carboxyl groups and two other oxygen atoms from the -NO groups, respectively, which leads to an infinite one dimensional chain. The two adjacent elongated Cu(Ⅱ) square pyramidal geometries are arranged in trans form in the same chain. The OH…O hydrogen bonds extend the chain structure into two-dimensional layers.

Synthesis and Crystal Structure of Zinc(II) Complex with Isonicotinate Containing a Three-dimensional Hydrogen-bond Network

A zinc complex, [Zn(iso)_2(H_2O)_4](iso=C_6H_4NO_2^-), was synthesized and characterized by elemental analysis, thermal analysis and IR spectrum studies. The crystal structure of the complex was determined by X-ray diffraction. The crystal crystallizes in the triclinic system, molecular formula ZnC12H16N2O8, Mr=381.64, space group P with a = 6.338(1), b =6.919(1), c=9.277(1), α=96.28(1), β=104.91(1), γ=112.85(1)°, V=352.12(9)?3, Z=1, Dc=1.80g?cm-3 and F(000)=196, μ =1.791mm-1. The crystal structure was solved by direct methods for final R=0.0204 and Rw=0.0542 for 1258 observed reflections with [Fo>4σ(Fo)]. The crystal structure reveals that zinc ion is trans-octahedral with two pyridyl nitrogens and two aque oxygens at the equational positions and two aqua oxygens at the axial positions. The complex forms a three-dimensional network through intermolecular hydrogen bonds.

Hydrothermal Synthesis and Characterization of a Novel Supramolecular Network Compound [Co(IN)_2(H_2O)_4](IN=Isonicotinate)

A novel supramolecular compound, [Co(IN)_2(H_2O)_4](1), was synthesized by means of the hydrothermal method and its structure was characterized with elemental analysis, FT-IR spectrum, TGA and X-ray diffraction. Though the unit cell structure of the title compound is only monomeric, all these units as building blocks are assembled into a novel three-dimensional supramolecular network via the widely hydrogen-bonding and π-π stacking interactions.

Syntheses and Structures of Lanthanide Complexes with Isonicotinate

The crystal structures of two coordination polymers [Ln(IN)3(H2O)2]n (Ln = Nd 1, Gd 2; IN = isonicotinate) were determined by single-crystal X-ray diffraction and further chara- cterized by IR, elemental analysis and thermogravimetric analysis. Crystal data for 1: monoclinic, space group P21/c, a = 9.6636(5), b = 19.7532(10), c = 11.6183(6) ?, β = 112.032(1)°, V = 2055.83(18) ?3, Z = 4, Dc = 1.766 g/cm3, F(000) = 1076, μ = 2.575 mm–1 and R = 0.0493; Crystal data for 2: monoclinic, space group C2/c, a = 20.251(2), b = 11.6199(11), c = 9.8240(9) ?, β = 115.505(3)°, V = 2086.4(3) ?3, Z = 4, Dc = 1.781 g/cm3, F(000) = 1092, μ = 3.228 mm–1 and R = 0.0695. In the title compounds, the center atoms Ln(III) are in a distorted square antiprismatic geometry and linked by bridging isonicotinate to form an infinite chain. The intermolecular hydro- gen bonds lead to the formation of three-dimensional supramolecular structures.

Syntheses and Structures of Three Novel 1-D Lanthanide-isonicotinate Coordination Polymers

Three novel lanthanide-IN coordination polymers [Ln（IN）3（H2O）2], （Ln = Sm 1, Dy 2, Eu 3; IN = isonicotinate） have been hydrothermally synthesized and characterized by FT-IR spectra, elemental analysis and TG analysis. Single-crystal X-ray diffraction shows that 1, 2 and 3 are isostructural. Crystal data for 1： monoclinic, space group C 2/c, a = 15.8384（14）, b = 14.2662 （12）, c = 9.5073（7） A, β = 97.705（4）°, V = 2128.8（3） A^3, Z = 4, Dc = 1.724 g/cm^3, F（000） = 1084 , μ = 2.806 mm^-1 and R = 0.0226; Crystal data for 2： monoclinic, space group C 2/c, a = 15.7890（3）, b = 14.1356（6）, c = 9.5152（3） A, β= 97.899（2）°, V = 2103.52（12） A^3, Z = 4, Dc = 1.784 g/cm^3, F（000） = 1100, μ = 3.601 mm^-1 and R = 0.0406; Crystal data for 3： monoclinic, space group C 2/c, a = 15.802（5）, b = 14.242（4）, c = 9.513（3） A, β = 97.695（5）°, V = 2121.8（10） A^3, Z = 4, Dc = 1.735 g/cm^3, F（000） = 1088 ,μ = 3.004 mm^-1 and R = 0.0273. In the three compounds, the Ln（Ⅲ） centers are eight-coordinated with antiprismatic geometry. The Ln（IN）3（H2O）2 unit connects mutually to form a one-dimensional double zigzag chain via isonicotinate oxygen bridging. The infinite chains are further linked by inter-chain hydrogen-bonding to form a three-dimensional supramolecular network.

x-ray Crystal Structure of a Dinuclear Zinc(Ⅱ) Complex with Unusual Two Monodentate O-coordination of Carboxylate Group of Isonicotinate

Reaction of Zn(ClO4)2·6H2O with septadentate 2,6-bis[bis(2-benzimidazolylme-thyl)amino methyl]-4-methylphenol (Hbbap) and sodium isonicotinate yielded a dinuclear zinc complex[Zn2(bbap) (Iso) (Hiso)] (ClO4)2·[Zn2 (bbap) (Iso) (H2O)] (ClO4)2·4H2O(1a·1b·4H2O). Hiso isisonicotinic acid and Iso is isonicotinate anion. The structure has been established by X-raycrystallography and shows that the two zinc ions are bridged by the phenoxy unit of bbap- ligand,and the presence of unusual monodentate O-coordination of carboxylate group from isonicotinicacid. The coordination geometry around the zinc ion is approximately trigonal bipyramidal.

X-ray Crystal Structure of a Mononuclear Copper (Ⅱ) Complex with Unusual Monodentate O-coordination of Carboxylate Group of Isonicotinate

Reaction of Cu(ClO4)2'6H2O with tripodal ligand tri s (2-benzi nd dazol yl methyl ) aInine(ntb) and sodium isonicotinate (Iso) yielded a mononuclear complex lCu(ntb)(lso)]ClO4.3.5H2O. Thestructure has been established by X-ray crystallography The Cu (Ⅱ) atom is in a distorted trigonalbipyranddal environment with three benzimindazole N atoms of ntb defining the equatorial plane, oneandne N atom of ntb, and one O atom of the carboxylate group of isonicotinate occupying the axialpositions.

Synthesis and Crystal Structure of Bis(N’-(Pyridine-3-Carboxaldehyde) Isonicotinoylhydrazone) Zinc(II)

Zinc complexes of Schiff base ligands exhibit interesting properties which could be exploited for potential applications as catalysts and models for biochemical systems. In this study, we report of the synthesis of a new zinc Schiff base complex, bis(N’-(pyridine-3-carboxaldehyde) isonicotinoylhydrazone) zinc(II), which has been characterized by physico-chemical methods. The X-ray single crystal structure of the complex has also been determined. The Schiff base ligand is bonded to the metal in a monodentate manner, coordinating through the pyridine N-atom, as shown from spectral studies. The crystal structure shows the zinc atom bonded to two Schiff bases and four aqua ligands, with each Schiff base ligand coordinating through its pyridine N-atom forming a distorted octahedral ZnN2O4 complex. Two water molecules and two nitrate ions found in the crystal structure link the different monomers through hydrogen bonding to form a layered supramolecular structure.

基于吹气分离富集的异烟酸-巴比妥酸分光光度法测定水中痕量氰化物

鉴于氰化物转化成氯化氰是HJ 484-2009中异烟酸-巴比妥酸分光光度法测定氰化物的独立中间环节,利用氯化氰沸点低(14℃)、稳定性好的特性,提出了基于吹气分离富集的异烟酸-巴比妥酸分光光度法测定水中痕量氰化物含量的方法。以空气为载气,以异烟酸质量浓度为17.20 g·L^(-1)、巴比妥酸质量浓度为8.40 g·L^(-1)的溶液为吸收液(pH 5.85),利用特定的分离富集装置,完成空气净化、氰化物转化成氯化氰、氯化氰分离、氯化氰吸收及转化成聚甲炔染料等一系列过程,采用分光光度计测定吸收液在600 nm处的吸光度。结果表明:当样品、吸收液的体积分别为60.0,5.00 mL,空气流量为0.10 L·min^(-1),采用3级吸收,以总吸光度作为响应值时,氰化物转化系数为94.2%,富集倍数为11.3倍,检出限(3s/k)为0.1μg·L^(-1),测定线性范围为0.4~28.3μg·L^(-1);方法用于井水及河水中痕量氰化物的测定,氰化物质量浓度为1.2~8.9μg·L^(-1),回收率为92.9%~104%。

地表水中氰化物测定方法的比对研究

本文采用异烟酸-吡唑啉酮分光光度法和连续流动分析法测定地表水中氰化物,对两种测定方法进行比对研究。结果表明,异烟酸-吡唑啉酮分光光度法和连续流动分析法测定地表水中氰化物时,精密度、准确度和回收率等都能满足测定要求。采用异烟酸-吡唑啉酮分光光度法测定地表水中氰化物时,操作过程烦琐且费时,分析人员工作强度大。采用连续流动分析法测定地表水中氰化物时,全自动分析过程不仅降低了分析人员工作强度,也有效避免氰化氢对分析人员健康造成损害,能更好地满足环境监测中大批量样品的分析测定需求。

含硫氰酸盐水质中低浓度氰化物的测定

黄金工业废水中常含有硫氰酸盐,测定低浓度氰化物时,存在测定结果偏高、重复性差等问题。研究建立了含硫氰酸盐水质中低浓度氰化物的测定方法,采用异烟酸-吡唑啉酮分光光度法测定馏出液中硫氰酸盐氰贡献值校准氰化物。本方法的精密度(RSD)小于4%,加标回收率为94%~102%,准确度和精密度良好。

4-氰基吡啶合成异烟酸菌种发酵工艺的研究

简单介绍了一株4-氰基吡啶合成异烟酸的菌种发酵工艺的研究,探究了不同碳源、氮源、诱导剂浓度、金属离子种类及金属离子浓度对发酵产腈水解酶酶活的影响,并对菌种高密度发酵工艺做了一系列优化,优化后的培养基对于该菌产腈水解酶的酶活达到了1076 U/mL,OD600达到了185,酶活对比优化前提高了40%。该菌在催化4-氰基吡啶合成异烟酸行业具有重要意义。

流动注射-异烟酸-巴比妥酸法分光光度法测定氰化物的测量不确定度评定

利用流动注射-异烟酸-巴比妥酸法分光光度法测定地表水中的氰化物,依据数学模型和检测过程的分析确定了测量不确定度的主要贡献因子并进行了评定,对测量结果明确了合理的表达方式。当地表水中氰化物含量为32.23μg·L^(-1)时,其扩展不确定度为0.78μg·L^(-1)。

多巴胺在聚异烟酸修饰玻碳电极上的电化学行为

目的 在抗坏血酸 (AA)存在下 ,用聚异烟酸修饰电极测定神经递质多巴胺 (DA)。方法 用循环伏安法和示差脉冲伏安法研究DA在聚异烟酸膜修饰电极上的伏安行为。结果 聚异烟酸膜修饰电极对DA有明显的电催化作用。该修饰电极使AA的氧化峰电位负移 ,与DA氧化峰电位分开达 2 0 4mV ,从而消除了对DA测定的干扰。DA在该修饰电极上的氧化峰电流与其浓度在 1 0× 10 - 7～ 2 0× 10 - 5和 2 0× 10 - 5～ 1 0× 10 - 4mol·L- 1 呈良好线性关系 ;检测限为 8 0× 10 - 9mol·L- 1 。结论 聚异烟酸膜修饰电极使用寿命至少 3周 。

异烟酸合成研究进展

综述了近年来国内外有关异烟酸合成方法的最新研究进展和成果。重点介绍了以聚4-吡啶乙烯、4-羟甲基吡啶、4-醛基吡啶和4-甲基吡啶为原料的化学氧化法,其中,以4-甲基吡啶为原料、空气/氧气为氧化剂的方法具有原料来源广泛、价格便宜、氧化剂清洁且廉价易得等优点,势必成为未来研究的热点。

4-甲基吡啶直接电氧化合成异烟酸工艺条件的研究

以Ti/PbO2为阳极,Pb为阴极,硫酸溶液为电解质,在阳离子交换膜为隔膜的H型电解槽中,直接电氧化4-甲基吡啶合成异烟酸,并考察了阳极电解液中4-甲基吡啶及硫酸浓度,通电量,电流密度和温度对异烟酸收率和电流效率的影响,得到的工艺条件为阳极电解液中4-甲基吡啶和硫酸的质量分数分别为10%和25%,通电量18.65(A.h),电解电流密度60 mA/cm2,60℃,在此条件下重复试验,异烟酸平均收率达到92.2%,平均电流效率50.9%。

新型三维配位聚合物[Fe(C_5H_4NCOO)_2]_n的可控合成、晶体结构和UV-VIS-NIR反射光谱研究

A novel coordination polymer, [Fe(C 5H 4NCOO) 2] n, was synthesized by hydrothermal reaction and characterized by elemental analysis as well as IR spectroscopy. The crystal structure (with a novel 3-D network) of this compound belongs to monoclinic, space group P2 1/n, a=0.49544(1) nm, b=1.32443(2) nm, c=1.04983(1) nm, β=101.586(1)°. The diffuse reflectance spectra (200～2500 nm) showed that the polymer had strong absorbance in 375～563 nm (E g≈2.5 eV) region and weak absorbance from 720 to 2500 nm (near infrared spectra).