Synthesis and Spectrophotometric Studies of 2-(1, 3, 4 -Triazolylazo) -5-Diethylamino Phenol and 2-(5-Carboxy-1, 3, 4-Triazolylazo) -5- Diethylamino Phenol

Inasearchfornewsensitiveandselectiveorganicreagents,athoroughstudyofsomeofthequinolylazo,pyridylazocompoundshasbeenreported'-'.Buttriazolylazocompoundshavenotbeenstudied.Inthispapef,2-(l,3,4-triazolylazo)-5-diethyIaminophenol(TZAPN)and2-(5-carboxy-l,3,4-triazoiylazo)-diethyIaminophenoI(CTZAPN)wereprepared,theconditionsofthisreactionwithcobaltwerestudied.Itwasfoundthatthereagentshadhighsensitivityandselectivityinthedeterminationofmicrogramamountsofcobaltundertheconditionsestablished.Thest…     

Study of 2-(2-quinolinylazo)-5-dimethylaminobenzoic acid as a new chromogenic reagent for the spectrophotometric determination of cobalt

2-(2-Quinolinylazo)-5-dimethylaminobenzoic acid (QADMAB) is proposed as a new sensitive and selective chromogenic reagent for spectrophotometric determination of cobalt. The QADMAB reacts with cobalt in the presence of cetyl trimethylammonium bromide (CTMAB) medium to form a violet complex of molar ratio 1:2 (cobalt to QADMAB) in the pH range 3.2-5.2. The molar absorptivity of the complex is 1.28x10(5) L mol(-1) cm(-1) at 625 nm. Beer's law is obeyed in range 0.01-0.32 micro g mL(-1). The relative standard deviation for eleven replicate samples of 0.2 micro g mL(-1) is 0.76%. This method was applied to the determination of cobalt in biological samples, Vitamin B(12), alloys and water with good results.     

Selective determination of cobalt using polyurethane foam and 2-(2-benzothiazolylazo)-2-p-cresol as a spectrophotometric reagent

The present work describes a selective, rapid and economical method for the determination of cobalt using the 2-(2-benzothiazolylazo)-p-cresol (BTAC) as a spectrophotometric reagent associated with a solid extraction on polyurethane foam. The BTAC reacts with Co(II) in the presence of Triton-X100 surfactant forming a green complex with maximum absorption at 615 nm. The reaction is used for cobalt determination within a pH range of 6.50-7.50, with an apparent molar absorptivity of 1.62 x 10(4) L mol(-1) cm(-1). Beer's Law is obeyed for a concentration of at least 1.60 microg ml(-1). A selective procedure is proposed for cobalt determination in the presence of Fe(II), Hg(II), Zn(II) and Cu(II) up to milligram levels using masking agents. Polyurethane foam is used for the preconcentration and separation of cobalt from thiocyanate media and this procedure is applied to its determination in nickel salts and steel alloys.     

新显色剂2-(2-噻唑偶氮)-5-二乙氨基苯甲酸分光光度法测定微量钴

近年来,杂环偶氮苯甲酸类显色剂取得了较快的发展。由于氨基取代结构对试剂性能有较大的影响^[1],因此本文合成了新显色剂2-(2-噻唑偶氮)-5-二乙氨基苯甲酸,(TAEB)并研究了它与钴的显色反应。     

8-喹啉偶氮显色剂QADCB的合成及其分析性能的研究

报道了8-喹啉偶氮显色剂2-(8-喹啉偶氮)-5-二羧甲氨基苯甲酸(QADCB)的合成、提纯与鉴定,研究了其与Co(Ⅱ)、Ni(Ⅱ)、Fe(Ⅲ)的显色反应,对QADCB与Co(Ⅱ)的显色反应作了研究。在pH5.9的缓冲体系中,试剂与Co(Ⅱ)形成棕红色配合物,其最大吸收波长位于650nm,表观摩尔吸光系数为4.2×104L.mol-1.cm-1,钴量在0~20μg/25mL范围内符合比耳定律。方法简便、快速,选择性较好,已用于纯铜、维生素B12中微量钴的测定,结果满意。     

Synthesis of 2-(3,5-dichloro-2-pyridylazo)-5-dimethylaminophenol and its application to the spectrophotometric determination of cobalt

2-(3,5-Dichloro-2-pyridylazo)-5-dimethylaminophenol (3,5-diCl-DMPAP) has been synthesized and its analytical application investigated. It reacts with cobalt in aqueous solution at pH 2.2-6.0 and room temperature to form a water-soluble ML(2) complex with absorption maximum at 590 nm, and molar absorptivity 8.4 x 10(4) l.mole(-1).cm(-1). Interference from other transition metals can be eliminated by their solvent extraction with 8-hydroxyquinoline. The method has been successfully applied to determination of cobalt in mild steels.     

5-(5-氟-2-吡啶偶氮)-2,4-二氨基甲苯与钴显色反应的研究及应用

研究了新合成试剂5-(5-氟-2-吡啶偶氮)-2,4-二氨基甲苯(5-F-PADAT)与钴(Ⅱ)的显色反应。实验表明,在pH4.7~9.0范围内,钴与试剂形成紫红色配合物,其最大吸收波长位于506 nm。该配合物在无机酸作用下,可转化为另一具有较高吸收特性的质子化型体,最大吸收波长红移到565 nm,适宜的酸浓度范围分别为:0.24~3.6 mol/L HClO4、0.16~3.84 mol/L H2SO4、0.48~2.4 mol/L HCl、0.64~3.84 mol/L H3PO4。配合物表观摩尔吸光系数ε565=9.1×104L.mol-1.cm-1,钴(Ⅱ)质量浓度在0~0.5μg/mL内符合比尔定律。所拟方法已应用于维生素B12针剂中微量钴的测定。     

Spectrophotometric determination of cobalt(II) with 2-[di-(2-pyridyl)-methylidenehydrazino]quinoline

A simple, rapid and selective procedure for spectrophotometric determination of cobalt has been developed. Cobalt(II) forms two water-soluble complexes with 2-[di-(2-pyridyl)methylidenehydrazino]quinoline, an orange-yellow complex (lambda(max) 510 nm) in the pH range 2-12 and a pink complex (lambda(max) 530 nm) in 0.1-6M perchloric acid medium. The molar absorptivities for the orange-yellow and pink complexes are 3.65 x 10(4) and 4.1 x 10(4) 1.mole(-1).cm(-1) and Beer's law is obeyed up to 1.84 and 2.0 ppm of cobalt(II) respectively. Cobalt(II) has also been determined in alloys.     

Crystal structure of bis(2-(2-thiazolylazo)-4-methylphenol)cobalt(III)chloride.

The reaction between CoCl2 x 6H2O and 2-1-(2-thiazolylazo)-p-cresol (TAC) in acetone resulted in six coordinated cobalt(III) complex, [Co(TAC)2]Cl3. Two TAC ligands coordinate with cobalt ion forming four five membered chelate rings. The cobalt ion is octahedrally coordinated by a phenolic oxygen, azo nitrogen and nitrogen in thiazole rings. Three chloride ions are disordered.     

Silaned glass beads for the preconcentration and spectrophotometric determination of cobalt with 2-(2-pyridylazo)-5-diethylaminophenol

Silaned glass beads are applied for the preconcentration and spectrophotometric determination of cobalt with 2-(2-pyridylazo)-5-diethylaminophenol (PADAP). Traces of cobalt are collected as the coloured PADAP complex on a column of the beads, and the complex is then eluted with a small volume of ethanol-hydrochloric acid mixture and the absorbance of the eluate is measured at 575 nm. The cobalt can easily be concentrated by a factor of 50-500 in this way, and 0.1-2 mug of cobalt in 100 ml of sample solution can be determined reproducibly. High concentrations of Fe(III), Cr(III), Pb, Zn, Cu(II), Mn(II), Cd, Al, Ca and Mg can be tolerated but Pd(II) interferes.     

Design and synthesis of a 4-(2'-pyridyl)-1,2,3,5-dithiadiazolyl cobalt complex

The 4-(2'-pyridyl)-1,2,3,5-dithiadiazolyl neutral radical 1 has been prepared for use as a spin-bearing bidentate ligand. The coordination of this ligand to bis(hexafluoroacetylacetonato)cobalt affords a thermally stable complex 2. Magnetic susceptibility measurements of the crystalline complex indicate ferromagnetic coupling between the ligand-centered spin and the unpaired electrons of the high-spin Co(II).     

[(R)-2-Methyl-1,4,7-triazacyclononane] [1,1,1-tris(aminomethyl)ethane]-cobalt(III) and some Mono[(R)-2-methyl-1,4,7-triazacyclononane]-cobalt(III) Complexes

Summary [(R)-2-Methyl-1,4,7-triazacyclononane][1,1,1-tris(aminomethyl)ethane]cobalt(III) has been prepared and separated into two isomers which show weak Cotton effects in the¹A₁¹T₁ region (d-electron transition) compared with that of bis[(R)-2-methyl-1,4,7-triazacyclononane]cobalt(III). The effect is comparable to that of tetraammine[(R)-1,2-diamino propane]cobalt(III). The circular dichroism spectra of the mono complex change markedly upon addition of sodium sulphate. The chelate rings are more flexible in the mono than in the bis complex. Some other related mono[(R)-2-methyl 1,4,7-triazacyclononane]cobalt(III) and [(R)-2-methyl-1,4,7 triazacyclononane][1,1,1-tris(aminomethyl)ethaneI nickel (II) complexes have also been prepared and characterized.     

Preconcentration of trace cobalt with the ion pair of 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol and tetraphenylborate onto microcrystalline naphthalene or column method and its determination by derivative spectrophotometry

Cobalt-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP)-tetraphenylborate ion associated complex is quantitatively adsorbed on microcrystalline naphthalene in the pH range 3.5-9.5 from a fairly large volume of the aqueous samples (preconcentration factor ~30). After filtration, the solid mass consisting of the cobalt complex and naphthalene was dissolved with 5 ml of dimethylformamide (DMF) and the metal determined by first-derivative spectrophotometry. The cobalt-5-Br-PADAP complex can alternatively be quantitatively retained on ammonium tetraphenylborate-naphthalene adsorbent filled in a column (preconcentration factor 120) in the same pH range and determined similarly. The detection limit is 30 ppb (signal-to-noise ratio=2) and the calibration curve is linear over 0.3-8.0 mug of cobalt in 5 ml of the final DMF solution. Eight replicate determinations of 1.0 mug of cobalt gave a mean peak height of 0.208 (at 611.5 nm) with a relative standard deviation of 1.2%. The sensitivity of the method is 1.04 (dA/dnm) ml mug(-1) found from the slope of the calibration curve. The interference of a large number of anions and cations on the determination of cobalt has been studied and the optimized conditions developed were utilized for its trace determination in various standard alloys and biological samples.     

Triton X-100存在下钴与α-(α-噻唑偶氮)-5-二甲氨基苯甲酸的胶束显色反应

本文简化并改进了2-(2-噻唑偶氮)-5-二甲氨基苯甲酸(TAMB)的合成方法. 详细研究了在非离子表面活性剂Triton X-100存在下TAMB与钴的胶束增敏显色反应.     

有机试剂结构与性质的研究Ⅷ.4-[(5-氯-2-吡啶)偶氮]-1,3-二氨基苯与钴络合反应机理的研究

本文应用吸收光谱、激光拉曼光谱及量子化学方法研究了5-Cl-PADAB及其钴络合物在不同酸度溶液中存在的形式及络合生色反应的机理,测定了钴络合物的质子化常数。     

新试剂5-(2'-氨基-4'-羟基苯偶氮)邻苯二甲酰肼(AHPP) 的合成及其光度法测定钴

本文新试剂5-(2'-氨基-4'-羟基苯偶氮)邻苯二甲酰肼的合成,并研究了该试剂用于光度法测定钴的反应条件,钴与试剂在pH7.7-9.0(0.06mol.L~-1Na~2B~ 4O~ 7-HCI缓冲介质)时形成稳定配合物,最大吸收位于542nm处,摩尔吸光率为5.7×10~L.mol~-~1.cm~-~1,配合物的组成为1:2的Co:AHPP,钴浓度在0-1.02×10~-~4mol.L~-~1范围内符合Beer'slaw.试验了共存离子的影响,发现除Cu(Ⅱ),Ni(Ⅱ)略有干扰(可掩敝)外,其它常见离子均允许大量存在,该法直接用于不锈钢和维生素B~1~2 中钴的测定.     

喹啉醛亚胺钴配合物催化丁二烯顺式-1,4选择性聚合

合成和表征了一系列以[NN]双齿喹啉醛亚胺为配体的二氯化钴配合物（1a~6a）。 以X射线单晶衍射技术分析了配合物2a、3a和4a的分子结构。 配合物2a和3a以单核四配位（2个氮原子和2个氯原子）的形式结晶,而配合物4a由于取代基空间位阻小,则以双核的形式结晶。 在倍半乙基氯化铝（EASC）的活化下,该催化体系引发丁二烯单体聚合,得到顺式-1,4结构含量高达98%的聚丁二烯。 催化剂催化活性随配体上取代基吸电子能力的增加而提高,但随取代基空间位阻的增加而降低。 所合成的聚丁二烯具有高相对分子质量(Mn约为2.0×105)和窄的相对分子质量分布（Mw/Mn＜2.7）。     

Migratory insertion of the R2P group into a nitrogen-nitrogen bond - a novel type of rearrangement in phosphorus-nitrogen ligand chemistry. 3. The rearrangement of triphosphinohydrazide ligand -N(PPh2)-N(PPh2)2 to triphosphazenide anion {[(Ph2P-N]2PPh2}- in the coordination sphere of divalent cobalt and nickel

Hydrazine dihydrochloride reacts with 3 equiv of Ph2PCl in tetrahydrofuran in the presence of triethylamine to give tris(diphenylphosphino)hydrazine (1) in 70% yield. Each nitrogen atom in 1 has a trigonal-planar environment according to X-ray analysis. Thermolysis of 1 at 130 degrees C results in the formation of two products: bis(diphenylphosphino)amine and octaphenylcyclotetraphosphazene. The interaction of free ligand 1 with NiBr2 affords a simple adduct [(Ph2P)2N-NH-PPh2]NiBr2, while its anionic (hydrazide) form undergoes rearrangement in a coordination sphere of divalent cobalt and nickel involving migratory insertion of the Ph2P group into a nitrogen-nitrogen bond. The reaction of 1 with cobalt bis(trimethylsilyl)amide, [(Me3Si)2N]2Co, yields the complex of phosphazenide-type (Me3Si)2N-Co[(Ph2PN)2PPh2] (2) in 86% yield. A similar reaction of 1 with nikelocene proceeds with substitution of one Cp ring to form durable 18-electron complex CpNi[(Ph2PN)2PPh2] (3).     

Spectrophotometric determination of cobalt(II) with 2-(3′-sulfobenzoyl)pyridine benzoylhydrazone

A simple method has been described for the Spectrophotometric determination of cobalt(II) with 2-(3′-sulfobenzoyl)pyridine benzoylhydrazone (SBPBH). In aqueous solution, cobalt(II) reacts with SBPBH to form a yellow complex, which is not destroyed even by the addition of 3.8 M perchloric acid. The absorption maximum of the complex in 1.5 M perchloric acid medium was found to be 400 nm; the molar absorptivity was 2.17 × 10⁴ liters mol⁻¹ cm⁻¹. The proposed method is fairly selective and has been applied to the determination of cobalt in standard alloy steel samples.     

o-Amino heterocyclic azo-dyes as analytical reagents-II Spectrophotometric determination of cobalt with 3-[(5-chloro-2-pyridyl)azo]-2,6-diaminopyridine

Cobalt(II) and 3-[(5-chloro-2-pyridyl)azo]-2,6-diaminopyridine (5-Cl-PADAPy) in slightly acid, neutral or alkaline media form a blue complex which is very stable even in the presence of mineral acids. The complex has two absorption maxima, at 575 and 620 nm. in 1.2M hydrochlororic acid. The system conforms to Beer's law; the optimal range for a 1-cm cell is 0.2-1.2 ppm cobalt. Milligram amounts of common anions and cations do not interfere. The molar absorptivity is 3.69 x 10(4) 1.mole(-1).cm(-1) at 620 nm.